Gerald Fuller

All Publications

• Antifoams in non-aqueous diesel fuels: Thin liquid film dynamics and antifoam mechanisms JOURNAL OF COLLOID AND INTERFACE SCIENCE Calhoun, S. K., Suja, V., Fowler, R., Agiral, A., Salem, K., Fuller, G. G. 2024; 675: 1059-1068

  Abstract

  HypothesisFoaming in diesel fuels is not well understood and leads to operational challenges. To combat deleterious effects of foaming, diesel formulations can include additives called antifoams. Existing antifoams, unfortunately, are inherently ash-generating when combusted, with unknown environmental impacts. They are prohibited in certain countries, so identifying effective alternative ash-free antifoam chemistries is needed. ExperimentsWe conduct systematic characterization of foam stabilization and antifoaming mechanisms in diesel for two different antifoams (silicone-containing & ashless chemistries). Employing a custom technique combining single-bubble/single-antifoam-droplet manipulation with white light interferometry, we also obtain mechanistic insights into foam stability and antifoam dynamics. ResultsCoalescence times from both bulk foam and single bubble experiments confirm ashless antifoams are effective at reducing foaming, demonstrating the potential of ashless antifoams. Further, we perform single-antifoam-droplet experiments and obtain direct experimental evidence revealing the elusive antifoaming mechanisms. Interestingly, the silicone-containing and ashless antifoams seemingly function via two different mechanisms: spreading and dewetting respectively. This surprising finding refutes conventional wisdom that spreading is likely the only antifoam mechanism in diesels. These results and the reported experimental framework significantly enhance the scientific understanding of non-aqueous foams and will accelerate the engineering of alternative antifoam chemistries for non-aqueous systems.

  View details for DOI 10.1016/j.jcis.2024.07.013

  View details for Web of Science ID 001271695300001

  View details for PubMedID 39013302

• Viscoelastic measurements of abscess fluids using a magnetic stress rheometer PHYSICS OF FLUIDS Shih, A., Chung, S. J., Shende, O. B., Herwald, S. E., Vezeridis, A. M., Fuller, G. G. 2024; 36 (11)

  View details for DOI 10.1063/5.0238703

  View details for Web of Science ID 001359618100025

• Elucidating the roles of electrolytes and hydrogen bonding in the dewetting dynamics of the tear film. Proceedings of the National Academy of Sciences of the United States of America Borkar, S., Baumli, P., Vance, T., Sharma, E., Shi, X., Wu, J. Y., Yao, G., Myung, D., Fuller, G. G. 2024; 121 (31): e2407501121

  Abstract

  This study explores the impact of electrostatic interactions and hydrogen bonding on tear film stability, a crucial factor for ocular surface health. While mucosal and meibomian layers have been extensively studied, the role of electrolytes in the aqueous phase remains unclear. Dry eye syndrome, characterized by insufficient tear quantity or quality, is associated with hyperosmolality, making electrolyte composition an important factor that might impact tear stability. Using a model buffer solution on a silica glass dome, we simulated physiologically relevant tear film conditions. Sodium chloride alone induced premature dewetting through salt crystal nucleation. In contrast, trace amounts of solutes with hydroxyl groups (sodium phosphate dibasic, potassium phosphate monobasic, and glucose) exhibited intriguing phenomena: quasi-stable films, solutal Marangoni-driven fluid influx increasing film thickness, and viscous fingering due to Saffman-Taylor instability. These observations are rationalized by the association of salt solutions with increased surface tension and the propensity of hydroxyl-group-containing solutes to engage in significant hydrogen bonding, altering local viscosity. This creates a viscosity contrast between the bulk buffer solution and the film region. Moreover, these solutes shield the glass dome, counteracting sodium chloride crystallization. These insights not only advance our understanding of tear film mechanics but also pave the way for predictive diagnostics in dry eye syndrome, offering a robust platform for personalized medical interventions based on individual tear film composition.

  View details for DOI 10.1073/pnas.2407501121

  View details for PubMedID 39042697

• Peroxidase-mediated mucin cross-linking drives pathologic mucus gel formation in IL-13-stimulated airway epithelial cells. JCI insight Liegeois, M. A., Braunreuther, M., Charbit, A. R., Raymond, W. W., Tang, M., Woodruff, P. G., Christenson, S. A., Castro, M., Erzurum, S. C., Israel, E., Jarjour, N. N., Levy, B. D., Moore, W. C., Wenzel, S. E., Fuller, G. G., Fahy, J. V. 2024

  Abstract

  Mucus plugs occlude airways to obstruct airflow in asthma. Studies in patients and in mouse models show that mucus plugs occur in the context of type 2 inflammation, and studies in human airway epithelial cells (HAECs) show that interleukin 13 (IL-13) activated cells generate pathologic mucus independently of immune cells. To determine how HAECs autonomously generate pathologic mucus, we used a magnetic microwire rheometer to characterize the viscoelastic properties of mucus secreted under varying conditions. We found that normal HAEC mucus exhibits viscoelastic liquid behavior and that mucus secreted by IL-13 activated HAECs exhibits solid-like behavior caused by mucin cross-linking. In addition, IL-13 activated HAECs show increased peroxidase activity in apical secretions, and an overlaid thiolated polymer (thiomer) solution shows an increase in solid behavior that is prevented by peroxidase inhibition. Furthermore, gene expression for thyroid peroxidase (TPO), but not lactoperoxidase (LPO), is increased in IL-13 activated HAECs and both TPO and LPO catalyze the formation of oxidant acids that cross-link thiomer solutions. Finally, gene expression for TPO in airway epithelial brushings is increased in asthma patients with high airway mucus plug scores. Together, our results show that IL-13 activated HAECs autonomously generate pathologic mucus via peroxidase-mediated cross-linking of mucin polymers.

  View details for DOI 10.1172/jci.insight.181024

  View details for PubMedID 38889046

• Air-liquid intestinal cell culture allows in situ rheological characterization of intestinal mucus. APL bioengineering Cai, P. C., Braunreuther, M., Shih, A., Spakowitz, A. J., Fuller, G. G., Heilshorn, S. C. 2024; 8 (2): 026112

  Abstract

  Intestinal health heavily depends on establishing a mucus layer within the gut with physical properties that strike a balance between being sufficiently elastic to keep out harmful pathogens yet viscous enough to flow and turnover the contents being digested. Studies investigating dysfunction of the mucus layer in the intestines are largely confined to animal models, which require invasive procedures to collect the mucus fluid. In this work, we develop a nondestructive method to study intestinal mucus. We use an air-liquid interface culture of primary human intestinal epithelial cells that exposes their apical surface to allow in situ analysis of the mucus layer. Mucus collection is not only invasive but also disrupts the mucus microstructure, which plays a crucial role in the interaction between mucus and the gut microbiome. Therefore, we leverage a noninvasive rheology technique that probes the mechanical properties of the mucus without removal from the culture. Finally, to demonstrate biomedical uses for this cell culture system, we characterize the biochemical and biophysical properties of intestinal mucus due to addition of the cytokine IL-13 to recapitulate the gut environment of Nippostrongylus brasiliensis infection.

  View details for DOI 10.1063/5.0187974

  View details for PubMedID 38721267

  View details for PubMedCentralID PMC11078553

• Influence of hydrophobic particles on the film drainage during bubble-solid interaction PHYSICS OF FLUIDS Dhara, P., Jung, B., Gala, L., Borkar, S., Fuller, G. G. 2024; 36 (3)

  View details for DOI 10.1063/5.0196809

  View details for Web of Science ID 001182753500006

• Response of lymphatic endothelial cells to combined spatial and temporal variations in fluid flow. FASEB journal : official publication of the Federation of American Societies for Experimental Biology Michalaki, E., Surya, V. N., Rodríguez-Hakim, M., Fuller, G. G., Dunn, A. R. 2023; 37 (12): e23240

  Abstract

  One-way valves within lymphatic vessels are required for the efficient drainage of lymphatic fluids. Fluid flow is proposed to be a key cue in regulating both the formation and maintenance of lymphatic valves. However, to our knowledge, no previous study has systematically examined the response of LECs to the complex combination of spatially and temporally varying fluid flows that occur at lymphatic valves in vivo. We built an in vitro microfluidic device that reproduces key aspects of the flow environment found at lymphatic valves. Using this device, we found that a combination of spatially and temporally varying wall shear stresses (WSSs) led to upregulated transcription of PROX1 and FOXC2. In addition, we observed that combined spatial and temporal variations in WSS-modulated Ca2+ signaling and led to increased cellular levels of NFATc1. These observations suggest that the physical cues generated by the flow environment present within lymphatic valves may act to activate key regulatory pathways that contribute to valve maintenance.

  View details for DOI 10.1096/fj.201902205RRRR

  View details for PubMedID 37902497

• Interfacial stresses on droplet interface bilayers using two photon fluorescence lifetime imaging microscopy. Journal of colloid and interface science Huang, Y., Chandran Suja, V., Yang, M., Malkovskiy, A. V., Tandon, A., Colom, A., Qin, J., Fuller, G. G. 2023; 653 (Pt B): 1196-1204

  Abstract

  Response of lipid bilayers to external mechanical stimuli is an active area of research with implications for fundamental and synthetic cell biology. Developing novel tools for systematically imposing mechanical strains and non-invasively mapping out interfacial (membrane) stress distributions on lipid bilayers can accelerate research in this field.We report a miniature platform to manipulate model cell membranes in the form of droplet interface bilayers (DIBs), and non-invasively measure spatio-temporally resolved interfacial stresses using two photon fluorescence lifetime imaging of an interfacially active molecular flipper (Flipper-TR). We established the effectiveness of the developed framework by investigating interfacial stresses accompanying three key processes associated with DIBs: thin film drainage between lipid monolayer coated droplets, bilayer formation, and bilayer separation.The measurements revealed fundamental aspects of DIBs including the existence of a radially decaying interfacial stress distribution post bilayer formation, and the simultaneous build up and decay of stress respectively at the bilayer corner and center during bilayer separation. Finally, utilizing interfacial rheology measurements and MD simulations, we also reveal that the tested molecular flipper is sensitive to membrane fluidity that changes with interfacial stress - expanding the scientific understanding of how molecular flippers sense stress.

  View details for DOI 10.1016/j.jcis.2023.09.092

  View details for PubMedID 37793246

• From improving eyesight to disease theranostics: The impact of ocular fluid mechanics research PHYSICS OF FLUIDS Suja, V., Fuller, G. G. 2023; 35 (8)

  View details for DOI 10.1063/5.0168773

  View details for Web of Science ID 001052323000006

• The Role of Membrane-Tethered Mucins in Axial Epithelial Adhesion in Controlled Normal Stress Environments. Advanced biology Baumli, P., Liu, C., Bekčić, A., Fuller, G. G. 2023: e2300043

  Abstract

  The collective adhesive behavior of epithelial cell layers mediated by complex macromolecular fluid environments plays a vital role in many biological processes. Mucins, a family of highly glycosylated proteins, are known to lubricate cell-on-cell contacts in the shear direction. However, the role of mucins mediating axial epithelial adhesion in the direction perpendicular to the plane of the cell sheet has received less attention. This article subjects cell-on-cell layers of live ocular epithelia that express mucins on their apical surfaces to compression/decompression cycles and tensile loading using a customized instrument. In addition to providing compressive moduli of native cell-on-cell layers, it is found that the mucin layer between the epithelia acts as a soft cushion between the epithelial cell layers. Decompression experiments reveal mucin layers act as soft, nonlinear springs in the axial direction. The cell-on-cell layers withstand decompression before fracturing by a cohesive failure within the mucin layer. When mucin deficiency is induced via a protease treatment, it is found that the axial adhesion between the cell layers is increased. The findings which correlate changes in biological factors with changes in mechanical properties might be of interest to challenges in ophthalmology, vision care, and mucus research.

  View details for DOI 10.1002/adbi.202300043

  View details for PubMedID 37271859

• Evaporation-driven gravitational instability in the liquid layer of a polymer solution: Theoretical and numerical studies PHYSICS OF FLUIDS Hong, J., Ahn, K., Fuller, G. G., Kim, M. 2023; 35 (6)

  View details for DOI 10.1063/5.0152147

  View details for Web of Science ID 001000481400007

• Coalescence of surface bubbles: The crucial role of motion-induced dynamic adsorption layer. Advances in colloid and interface science Zawala, J., Miguet, J., Rastogi, P., Atasi, O., Borkowski, M., Scheid, B., Fuller, G. G. 2023; 317: 102916

  Abstract

  The formation of motion-induced dynamic adsorption layers of surfactants at the surface of rising bubbles is a widely accepted phenomenon. Although their existence and formation kinetics have been theoretically postulated and confirmed in many experimental reports, the investigations primarily remain qualitative in nature. In this paper we present results that, to the best of our knowledge, provide a first quantitative proof of the influence of the dynamic adsorption layer on drainage dynamics of a single foam film formed under dynamic conditions. This is achieved by measuring the drainage dynamics of single foam films, formed by air bubbles of millimetric size colliding against the interface between n-octanol solutions and air. This was repeated for a total of five different surfactant concentrations and two different liquid column heights. All three steps preceding foam film rupture, namely the rising, bouncing and drainage steps, were sequentially examined. In particular, the morphology of the single film formed during the drainage step was analyzed considering the rising and bouncing history of the bubble. It was found that, depending on the motion-induced state of adsorption layer at the bubble surface during the rising and the bouncing steps, single foam film drainage dynamics can be spectacularly different. Using Direct Numerical Simulations (DNS), it was revealed that surfactant redistribution can occur at the bubble surface as a result of the bouncing dynamics (approach-bounce cycles), strongly affecting the interfacial mobility, and leading to slower rates of foam film drainage. Since the bouncing amplitude directly depends on the rising velocity, which correlates in turn with the adsorption layer of surfactants at the bubble surface during the rising step, it is demonstrated that the lifetime of surface bubbles should intimately be related to the history of their formation.

  View details for DOI 10.1016/j.cis.2023.102916

  View details for PubMedID 37269558

• Nondestructive rheological measurements of biomaterials with a magnetic microwire rheometer JOURNAL OF RHEOLOGY Braunreuther, M., Liegeois, M., Fahy, J. V., Fuller, G. G. 2023; 67 (2): 579-588

  View details for DOI 10.1122/8.0000606

  View details for Web of Science ID 000939549000001

• Stable High-Concentration Monoclonal Antibody Formulations Enabled by an Amphiphilic Copolymer Excipient. Advanced therapeutics Klich, J. H., Kasse, C. M., Mann, J. L., Huang, Y., d'Aquino, A. I., Grosskopf, A. K., Baillet, J., Fuller, G. G., Appel, E. A. 2023; 6 (1)

  Abstract

  Monoclonal antibodies are a staple in modern pharmacotherapy. Unfortunately, these biopharmaceuticals are limited by their tendency to aggregate in formulation, resulting in poor stability and often requiring low concentration drug formulations. Moreover, existing excipients designed to stabilize these formulations are often limited by their toxicity and tendency to form particles such as micelles. Here, we demonstrate the ability of a simple "drop-in", amphiphilic copolymer excipient to enhance the stability of high concentration formulations of clinically-relevant monoclonal antibodies without altering their pharmacokinetics or injectability. Through interfacial rheology and surface tension measurements, we demonstrate that the copolymer excipient competitively adsorbs to formulation interfaces. Further, through determination of monomeric composition and retained bioactivity through stressed aging, we show that this excipient confers a significant stability benefit to high concentration antibody formulations. Finally, we demonstrate that the excipient behaves as an inactive ingredient, having no significant impact on the pharmacokinetic profile of a clinically relevant antibody in mice. This amphiphilic copolymer excipient demonstrates promise as a simple formulation additive to create stable, high concentration antibody formulations, thereby enabling improved treatment options such as a route-of-administration switch from low concentration intravenous (IV) to high concentration subcutaneous (SC) delivery while reducing dependence on the cold chain.

  View details for DOI 10.1002/adtp.202200102

  View details for PubMedID 36684707

  View details for PubMedCentralID PMC9854243

• Instability and symmetry breaking of surfactant films over an air bubble JOURNAL OF FLUID MECHANICS Shi, X., Fuller, G. G., Shaqfeh, E. G. 2022; 953

  View details for DOI 10.1017/jfm.2022.888

  View details for Web of Science ID 000895812600001

• Kitchen flows: Making science more accessible,affordable, and curiosity driven PHYSICS OF FLUIDS Fuller, G. G., Lisicki, M., Mathijssen, A. M., Mossige, E. L., Pasquino, R., Prakash, V. N., Ramos, L. 2022; 34 (11)

  View details for DOI 10.1063/5.0131565

  View details for Web of Science ID 000883764300014

• Stable High-Concentration Monoclonal Antibody Formulations Enabled by an Amphiphilic Copolymer Excipient ADVANCED THERAPEUTICS Klich, J. H., Kasse, C. M., Mann, J. L., Huang, Y., D'Aquino, A., Grosskopf, A. K., Baillet, J., Fuller, G. G., Appel, E. A. 2022

  View details for DOI 10.1002/adtp.202200102

  View details for Web of Science ID 000870541300001

• Effect of Recombinant Human Lubricin on Model Tear Film Stability. Translational vision science & technology Cui, K. W., Xia, V. X., Cirera-Salinas, D., Myung, D., Fuller, G. G. 2022; 11 (9): 9

  Abstract

  Purpose: To investigate and quantify the effect of recombinant human lubricin (rh-lubricin) on model tear film stability.Methods: A custom-built, interferometry-based instrument called the Interfacial Dewetting and Drainage Optical Platform was used to create and record the spatiotemporal evolution of model acellular tear films. Image segmentation and analysis was performed in MATLAB to extract the most essential features from the wet area fraction versus time curve, namely the evaporative break-up time and the final wet area fraction (A10). These two parameters indicate the tear film stability in the presence of rh-lubricin in its unstressed and stressed forms.Results: Our parameters successfully captured the trend of increasing tear film stability with increasing rh-lubricin concentration, and captured differences in rh-lubricin efficacy after various industrially relevant stresses. Specifically, aggregation and fragmentation caused by a 4-week, high temperature stress condition negatively impacted rh-lubricin's ability to maintain model tear film stability. Adsorbed rh-lubricin alone was not sufficient to resist break-up and maintain full area coverage of the model tear film surface.Conclusions: Our results demonstrate that fragmentation and aggregation can negatively impact rh-lubricin's ability to maintain a stable tear film. In addition, the ability of rh-lubricin to maintain wetted area coverage is due to both freely dispersed and adsorbed rh-lubricin.Translational Relevance: Our platform and analysis method provide a facile, intuitive, and clinically relevant means to quantify the effect of ophthalmic drugs and formulations intended for improving tear film stability, as well as capture differences between variants related to drug stability and efficacy.

  View details for DOI 10.1167/tvst.11.9.9

  View details for PubMedID 36112103

• Tear Film Stability as a Function of Tunable Mucin Concentration Attached to Supported Lipid Bilayers JOURNAL OF PHYSICAL CHEMISTRY B Cui, K. W., Myung, D. J., Fuller, G. G. 2022

  View details for DOI 10.1021/acs.jpcb.2c04154AJ

  View details for Web of Science ID 000842923500001

• Tear Film Stability as a Function of Tunable Mucin Concentration Attached to Supported Lipid Bilayers. The journal of physical chemistry. B Cui, K. W., Myung, D. J., Fuller, G. G. 2022

  Abstract

  In this work, we describe the development of a tunable, acellular in vitro model of the mucin layer of the human tear film. First, supported lipid bilayers (SLBs) comprised of the phospholipid DOPC (1,2-dioleoyl-sn-glycero-3-phosphocholine) and biotinyl cap PE (1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-(cap biotinyl)) are created on the surface of a glass dome with radius of curvature comparable to the human eye. Next, biotinylated bovine submaxillary mucins (BSM) are tethered onto the SLB using streptavidin protein. The mucin presentation can be tuned by altering the concentration of biotinylated BSM, which we confirm using fluorescence microscopy. Due to the optically smooth surface that results, this model is compatible with interferometry for monitoring film thickness. Below a certain level of mucin coverage, we observe short model tear film breakup times, mimicking a deficiency in membrane-associated mucins. In contrast, the breakup time is significantly delayed for SLBs with high mucin coverage. Because no differences in mobility or wettability were observed, we hypothesize that higher mucin coverage provides a thicker hydrated layer that can protect against external disturbances to thin film stability. This advance paves the way for a more physiological, interferometry-based in vitro model for investigating tear film breakup.

  View details for DOI 10.1021/acs.jpcb.2c04154

  View details for PubMedID 35972346

• Influence of salt on the formation and separation of droplet interface bilayers PHYSICS OF FLUIDS Huang, Y., Suja, V., Amirthalingam, L., Fuller, G. G. 2022; 34 (6)

  View details for DOI 10.1063/5.0096591

  View details for Web of Science ID 000876609700015

• Systematic characterization of effect of flow rates and buffer compositions on double emulsion droplet volumes and stability. Lab on a chip Calhoun, S. G., Brower, K. K., Suja, V. C., Kim, G., Wang, N., McCully, A. L., Kusumaatmaja, H., Fuller, G. G., Fordyce, P. M. 2022

  Abstract

  Double emulsion droplets (DEs) are water/oil/water droplets that can be sorted via fluorescence-activated cell sorting (FACS), allowing for new opportunities in high-throughput cellular analysis, enzymatic screening, and synthetic biology. These applications require stable, uniform droplets with predictable microreactor volumes. However, predicting DE droplet size, shell thickness, and stability as a function of flow rate has remained challenging for monodisperse single core droplets and those containing biologically-relevant buffers, which influence bulk and interfacial properties. As a result, developing novel DE-based bioassays has typically required extensive initial optimization of flow rates to find conditions that produce stable droplets of the desired size and shell thickness. To address this challenge, we conducted systematic size parameterization quantifying how differences in flow rates and buffer properties (viscosity and interfacial tension at water/oil interfaces) alter droplet size and stability, across 6 inner aqueous buffers used across applications such as cellular lysis, microbial growth, and drug delivery, quantifying the size and shell thickness of >22000 droplets overall. We restricted our study to stable single core droplets generated in a 2-step dripping-dripping formation regime in a straightforward PDMS device. Using data from 138 unique conditions (flow rates and buffer composition), we also demonstrated that a recent physically-derived size law of Wang et al. can accurately predict double emulsion shell thickness for >95% of observations. Finally, we validated the utility of this size law by using it to accurately predict droplet sizes for a novel bioassay that requires encapsulating growth media for bacteria in droplets. This work has the potential to enable new screening-based biological applications by simplifying novel DE bioassay development.

  View details for DOI 10.1039/d2lc00229a

  View details for PubMedID 35593127

• A Mucin-Deficient Ocular Surface Mimetic Platform for Interrogating Drug Effects on Biolubrication, Antiadhesion Properties, and Barrier Functionality. ACS applied materials & interfaces Madl, A. C., Liu, C., Cirera-Salinas, D., Fuller, G. G., Myung, D. 2022

  Abstract

  Dry eye disease (DED) affects more than 100 million people worldwide, causing significant patient discomfort and imposing a multi-billion-dollar burden on global health care systems. In DED patients, the natural biolubrication process that facilitates pain-free blinking goes awry due to an imbalance of lipids, aqueous medium, and mucins in the tear film, resulting in ocular surface damage. Identifying strategies to reduce adhesion and shear stresses between the ocular surface and the conjunctival cells lining the inside of the eyelid during blink cycles is a promising approach to improve the signs and symptoms of DED. However, current preclinical models for screening ocular lubricants rely on scarce, heterogeneous tissue samples or model substrates that do not capture the complex biochemical and biophysical cues present at the ocular surface. To recapitulate the hierarchical architecture and phenotype of the ocular interface for preclinical drug screening, we developed an in vitro mucin-deficient DED model platform that mimics the complexity of the ocular interface and investigated its utility in biolubrication, antiadhesion, and barrier protection studies using recombinant human lubricin, a promising investigational therapy for DED. The biomimetic platform recapitulated the pathological changes in biolubrication, adhesion, and barrier functionality often observed in mucin-deficient DED patients and demonstrated that recombinant human lubricin can reverse the damage induced by mucin loss in a dose- and conformation-dependent manner. Taken together, these results highlight the potential of the platform─and recombinant human lubricin─in advancing the standard of care for mucin-deficient DED patients.

  View details for DOI 10.1021/acsami.1c22280

  View details for PubMedID 35416028

• A shape stability model for 3D printable biopolymer-bound soil composite CONSTRUCTION AND BUILDING MATERIALS Biggerstaff, A., Lepech, M., Fuller, G., Loftus, D. 2022; 321

  View details for DOI 10.1016/j.conbuildmat.2022.126337

  View details for Web of Science ID 000752204500001

• Interfacial Assembly of Graphene Oxide: From Super Elastic Interfaces to Liquid-in-Liquid Printing ADVANCED MATERIALS INTERFACES Kamkar, M., Erfanian, E., Bazazi, P., Ghaffarkhah, A., Sharif, F., Xie, G., Kannan, A., Arjmand, M., Hejazi, S., Russell, T. P., Fuller, G. G., Sundararaj, U. 2021

  View details for DOI 10.1002/admi.202101659

  View details for Web of Science ID 000730252000001

• Determining the yield stress of a Biopolymer-bound Soil Composite for extrusion-based 3D printing applications CONSTRUCTION AND BUILDING MATERIALS Biggerstaff, A., Fuller, G., Lepech, M., Loftus, D. 2021; 305

  View details for DOI 10.1016/j.conbuildmat.2021.124730

  View details for Web of Science ID 000697236600008

• Flowering in bursting bubbles with viscoelastic interfaces. Proceedings of the National Academy of Sciences of the United States of America Tammaro, D., Chandran Suja, V., Kannan, A., Gala, L. D., Di Maio, E., Fuller, G. G., Maffettone, P. L. 2021; 118 (30)

  Abstract

  The lifetime of bubbles, from formation to rupture, attracts attention because bubbles are often present in natural and industrial processes, and their geometry, drainage, coarsening, and rupture strongly affect those operations. Bubble rupture happens rapidly, and it may generate a cascade of small droplets or bubbles. Once a hole is nucleated within a bubble, it opens up with a variety of shapes and velocities depending on the liquid properties. A range of bubble rupture modes are reported in literature in which the reduction of a surface energy drives the rupture against inertial and viscous forces. The role of surface viscoelasticity of the liquid film in this colorful scenario is, however, still unknown. We found that the presence of interfacial viscoelasticity has a profound effect in the bubble bursting dynamics. Indeed, we observed different bubble bursting mechanisms upon the transition from viscous-controlled to surface viscoelasticity-controlled rupture. When this transition occurs, a bursting bubble resembling the blooming of a flower is observed. A simple modeling argument is proposed, leading to the prediction of the characteristic length scales and the number and shape of the bubble flower petals, thus paving the way for the control of liquid formulations with surface viscoelasticity as a key ingredient. These findings can have important implications in the study of bubble dynamics, with consequences for the numerous processes involving bubble rupture. Bubble flowering can indeed impact phenomena such as the spreading of nutrients in nature or the life of cells in bioreactors.

  View details for DOI 10.1073/pnas.2105058118

  View details for PubMedID 34301872

• Engineering Insulin Cold Chain Resilience to Improve Global Access. Biomacromolecules Maikawa, C. L., Mann, J. L., Kannan, A., Meis, C. M., Grosskopf, A. K., Ou, B. S., Autzen, A. A., Fuller, G. G., Maahs, D. M., Appel, E. A. 2021

  Abstract

  There are 150 million people with diabetes worldwide who require insulin replacement therapy, and the prevalence of diabetes is rising the fastest in middle- and low-income countries. The current formulations require costly refrigerated transport and storage to prevent loss of insulin integrity. This study shows the development of simple "drop-in" amphiphilic copolymer excipients to maintain formulation integrity, bioactivity, pharmacokinetics, and pharmacodynamics for over 6 months when subjected to severe stressed aging conditions that cause current commercial formulation to fail in under 2 weeks. Further, when these copolymers are added to Humulin R (Eli Lilly) in original commercial packaging, they prevent insulin aggregation for up to 4 days at 50 °C compared to less than 1 day for Humulin R alone. These copolymers demonstrate promise as simple formulation additives to increase the cold chain resilience of commercial insulin formulations, thereby expanding global access to these critical drugs for treatment of diabetes.

  View details for DOI 10.1021/acs.biomac.1c00474

  View details for PubMedID 34213889

• Mucin-Like Glycoproteins Modulate Interfacial Properties of a Mimetic Ocular Epithelial Surface. Advanced science (Weinheim, Baden-Wurttemberg, Germany) Liu, C., Madl, A. C., Cirera-Salinas, D., Kress, W., Straube, F., Myung, D., Fuller, G. G. 2021: e2100841

  Abstract

  Dry eye disease (DED) has high personal and societal costs, but its pathology remains elusive due to intertwined biophysical and biochemical processes at the ocular surface. Specifically, mucin deficiency is reported in a subset of DED patients, but its effects on ocular interfacial properties remain unclear. Herein a novel in vitro mucin-deficient mimetic ocular surface (Mu-DeMOS) with a controllable amount of membrane-tethered mucin molecules is developed to represent the diseased ocular surfaces. Contact angle goniometry on mimetic ocular surfaces reveals that high surface roughness, but not the presence of hydrophilic mucin molecules, delivers constant hydration over native ocular surface epithelia. Live-cell rheometry confirms that the presence of mucin-like glycoproteins on ocular epithelial cells reduces shear adhesive strength at cellular interfaces. Together, optimal surface roughness and surface chemistry facilitate sustainable lubrication for healthy ocular surfaces, while an imbalance between them contributes to lubrication-related dysfunction at diseased ocular epithelial surfaces. Furthermore, the restoration of low adhesive strength at Mu-DeMOS interfaces through a mucin-like glycoprotein, recombinant human lubricin, suggests that increased frictional damage at mucin-deficient cellular surfaces may be reversible. More broadly, these results demonstrate that Mu-DeMOS is a promising platform for drug screening assays and fundamental studies on ocular physiology.

  View details for DOI 10.1002/advs.202100841

  View details for PubMedID 34184839

• Instability and symmetry breaking in binary evaporating thin films over a solid spherical dome JOURNAL OF FLUID MECHANICS Shi, X., Rodriguez-Hakim, M., Shaqfeh, E. G., Fuller, G. G. 2021; 915

  View details for DOI 10.1017/jfm.2021.136

  View details for Web of Science ID 000627900300001

• Adsorption and Aggregation of Monoclonal Antibodies at Silicone Oil-Water Interfaces. Molecular pharmaceutics Kannan, A., Shieh, I. C., Negulescu, P. G., Chandran Suja, V., Fuller, G. G. 2021

  Abstract

  Monoclonal antibody (mAb) therapies are rapidly growing for the treatment of various diseases like cancer and autoimmune disorders. Many mAb drug products are sold as prefilled syringes and vials with liquid formulations. Typically, the walls of prefilled syringes are coated with silicone oil to lubricate the surfaces during use. MAbs are surface-active and adsorb to these silicone oil-solution interfaces, which is a potential source of aggregation. We studied formulations containing two different antibodies, mAb1 and mAb2, where mAb1 aggregated more when agitated in the presence of an oil-water interface. This directly correlated with differences in surface activity of the mAbs, studied with interfacial tension, surface mass adsorption, and interfacial rheology. The difference in interfacial properties between the mAbs was further reinforced in the coalescence behavior of oil droplets laden with mAbs. We also looked at the efficacy of surfactants, typically added to stabilize mAb formulations, in lowering adsorption and aggregation of mAbs at oil-water interfaces. We showed the differences between poloxamer-188 and polysorbate-20 in competing with mAbs for adsorption to interfaces and in lowering particulate and overall aggregation. Our results establish a direct correspondence between the adsorption of mAbs at oil-water interfaces and aggregation and the effect of surfactants in lowering aggregation by competitively adsorbing to these interfaces.

  View details for DOI 10.1021/acs.molpharmaceut.0c01113

  View details for PubMedID 33656340

• Dynamics of freely suspended drops translating through miscible environments PHYSICS OF FLUIDS Mossige, E., Chandran Suja, V., Walls, D. J., Fuller, G. G. 2021; 33 (3)

  View details for DOI 10.1063/5.0041536

  View details for Web of Science ID 000629635600001

• Interfacial and Cohesive Properties of Corneal Epithelium Liu, C., Fuller, G. G. CELL PRESS. 2021: 169A

  View details for Web of Science ID 000629601401071

• Surface energy and separation mechanics of droplet interface phospholipid bilayers. Journal of the Royal Society, Interface Huang, Y., Chandran Suja, V., Tajuelo, J., Fuller, G. G. 2021; 18 (175): 20200860

  Abstract

  Droplet interface bilayers are a convenient model system to study the physio-chemical properties of phospholipid bilayers, the major component of the cell membrane. The mechanical response of these bilayers to various external mechanical stimuli is an active area of research because of its implications for cellular viability and the development of artificial cells. In this article, we characterize the separation mechanics of droplet interface bilayers under step strain using a combination of experiments and numerical modelling. Initially, we show that the bilayer surface energy can be obtained using principles of energy conservation. Subsequently, we subject the system to a step strain by separating the drops in a step-wise manner, and track the evolution of the bilayer contact angle and radius. The relaxation time of the bilayer contact angle and radius along with the decay magnitude of the bilayer radius were observed to increase with each separation step. By analysing the forces acting on the bilayer and the rate of separation, we show that the bilayer separates primarily through the peeling process with the dominant resistance to separation coming from viscous dissipation associated with corner flows. Finally, we explain the intrinsic features of the observed bilayer separation by means of a mathematical model comprising the Young-Laplace equation and an evolution equation. We believe that the reported experimental and numerical results extend the scientific understanding of lipid bilayer mechanics, and that the developed experimental and numerical tools offer a convenient platform to study the mechanics of other types of bilayers.

  View details for DOI 10.1098/rsif.2020.0860

  View details for PubMedID 33530859

• Modeling and Restoring the Tear Film CURRENT OPHTHALMOLOGY REPORTS Madl, A. C., Fuller, G. F., Myung, D. 2020; 8 (4): 281-300

  View details for DOI 10.1007/s40135-020-00258-6

  View details for Web of Science ID 000702475800011

• In-Use Interfacial Stability of Monoclonal Antibody Formulations Diluted in Saline i.v. Bags. Journal of pharmaceutical sciences Kannan, A., Shieh, I. C., Hristov, P., Fuller, G. G. 2020

  Abstract

  The use of monoclonal antibodies (mAbs) for the treatment of a variety of diseases is rapidly growing each year. Many mAbs are administered intravenously using i.v. bags containing 0.9% NaCl (normal saline). We studied the aggregation propensity of these antibody solutions in saline and compared it with a low ionic strength formulation buffer. The mAb studied in this work is prone to aggregate, and is known to form a viscoelastic network at the air-solution interface. We observed that this interfacial elasticity increased when formulated in saline. In the bulk, the mAbs exhibited a tendency to self-associate that was higher in saline. We also studied the aggregation of the mAbs in the presence of polysorbate-20, typically added to formulations to mitigate interfacial aggregation. We observed that with surfactants, the presence of salt in the buffer led to a greater mAb adsorption at the interface and resulted in the formation of more particulate aggregates. Our results show that the addition of salt to the buffer led to differences in the interfacial aggregation in mAb formulations, showing that stress studies used to screen for mAb aggregation intended for i.v. administration should be performed in conditions representative of their intended route of administration.

  View details for DOI 10.1016/j.xphs.2020.10.036

  View details for PubMedID 33141046

• Understanding the adsorption and potential tear film stability properties of recombinant human lubricin and bovine submaxillary mucins in an in vitro tear film model. Colloids and surfaces. B, Biointerfaces Rabiah, N. I., Sato, Y., Kannan, A., Kress, W., Straube, F., Fuller, G. G. 2020; 195: 111257

  Abstract

  The wetting and adsorption properties for two glycoproteins, recombinant human lubricin and bovine submaxillary mucins (BSM) were evaluated on hydrophilic and hydrophobic glass dome surfaces in a simplified in vitro tear film model. We show that both recombinant human lubricin (rh-lubricin) and BSM solutions render surfaces hydrophilic and when the fluid films reach 500 nm or less, the fluids resist evaporation-driven breakup through a volumetric flux across the surface, which we believe is due to evaporation-driven solutocapillary flows. rh-Lubricin was able to maintain a wet film without spontaneous breakup for longer periods of time than BSM at lower concentrations, which we attribute to differences in adsorption properties, measured by QCM-D, that result from surface charge and structural differences (confirmed by zeta potential, DLS, and SAXS measurements).

  View details for DOI 10.1016/j.colsurfb.2020.111257

  View details for PubMedID 32712549

• Asphaltene-induced spontaneous emulsification: Effects of interfacial co-adsorption and viscoelasticity JOURNAL OF RHEOLOGY Rodriguez-Hakim, M., Anand, S., Tajuelo, J., Yao, Z., Kannan, A., Fuller, G. G. 2020; 64 (4): 799–816

  View details for DOI 10.1122/1.5145307

  View details for Web of Science ID 000537740000003

• Polymeric-nanofluids stabilized emulsions: Interfacial versus bulk rheology. Journal of colloid and interface science Kamkar, M., Bazazi, P., Kannan, A., Suja, V. C., Hejazi, S. H., Fuller, G. G., Sundararaj, U. 2020; 576: 252–63

  Abstract

  HYPOTHESIS: The properties of oil-in-water emulsions are influenced by the rheology of the aqueous phase (continuous phase) and the rheology of the oil-water interfaces. The bulk and interfacial rheological parameters can be tuned by incorporating nanoparticles (NPs) featuring different surface chemistries and polymers with different chemical or physical structures. Therefore, NPs and polymers can be used to formulate emulsions with different properties.EXPERIMENTS: The viscoelasticity at the oil-(aqueous phase) interface and the bulk viscoelasticity of aqueous phase were investigated in the presence of different fumed silica NPs (i.e., hydrophilic, hydrophobic, and slightly hydrophobic) and polymers with two different molecular weights. Bulk and interfacial viscoelastic properties were investigated, employing oscillatory rheological techniques. Furthermore, morphology and stability of the oil-in-(aqueous nanofluid) emulsions were explored utilizing bulk emulsification and single drop coalescence experiments.FINDINGS: Introducing polymers into the aqueous nanofluids had opposite effects on bulk and interfacial viscoelasticity. Despite the significant increase in bulk viscoelasticity upon addition of polymers into the aqueous nanofluids, the interfacial viscoelasticity and emulsion stability considerably decreased. The slightly hydrophobic NP nanofluids without polymers showed no bulk viscoelasticity, but displayed the highest interfacial viscoelasticity and emulsion stability. This provided us a unique opportunity to unravel the importance of bulk and interfacial viscoelasticity on oil-in-water emulsification and proved the dominant role of interfacial viscoelasticity over bulk viscoelasticity on emulsion stability.

  View details for DOI 10.1016/j.jcis.2020.04.105

  View details for PubMedID 32422449

• Tuning corneal epithelial cell adhesive strength with varying crosslinker content in silicone hydrogel materials. Translational vision science & technology Liu, C., Scales, C. W., Fuller, G. G. 2020; 9 (6): 3

  Abstract

  Purpose: To quantify the effect of silicone hydrogel crosslink density on the adhesion at corneal epithelial cells/silicone hydrogel contact lens interface.Methods: A custom-built rheometer, referred to as the live cell monolayer rheometer, was used to measure the adhesive strengths between corneal epithelial cell monolayers and silicone hydrogel lens surfaces. The resulting stress relaxations of senofilcon A-derived silicone hydrogel materials with varying crosslinking densities and delefilcon A were tested. Senofilcon A-like materials labeled L1, L2, L3, L4, and L5 contained crosslinker concentrations of 1.2, 1.35, 1.5, 1.65, and 1.8 wt%, respectively. The residual modulus measured from the live cell monolayer rheometer provided a direct indication of adhesive attachment.Results: Within the senofilcon-derived series, the adhesive strength shows a surprising minimum with respect to crosslink density. Specifically, L1 (1.20%) has the highest adhesive strength of 39.5 ± 11.2 Pa. The adhesive strength diminishes to a minimum of 11.2 ± 2.1 Pa for L3, whereafter it increases to 14.5 ± 2.5 Pa and 18.1 ± 5.1 Pa for L4 and L5, respectively. The delefilcon A lens exhibits a comparable adhesive strength of 27.8 ± 6.3 Pa to L1.Conclusions: These results demonstrated that increasing the crosslink density has a nonmonotonic influence on the adherence of lenses to mucin-expressing corneal epithelial cells, which suggests a competition mechanism at the cell/lens interface.Translational Relevance: Because the adhesiveness of contact lenses to ocular tissues may impact the comfort level for lens wearers and affect ease of removal, this study suggests that lens adhesion can be optimized through the control of crosslink density.

  View details for DOI 10.1167/tvst.9.6.3

  View details for PubMedID 32821500

• Oscillatory spontaneous dimpling in evaporating curved thin films JOURNAL OF FLUID MECHANICS Shi, X., Fuller, G. G., Shaqfeh, E. G. 2020; 889

  View details for DOI 10.1017/jfm.2020.92

  View details for Web of Science ID 000515191000001

• Surfactant-laden bubble dynamics under porous polymer films. Journal of colloid and interface science Kannan, A., Hristov, P., Li, J., Zawala, J., Gao, P., Fuller, G. G. 2020; 575: 298–305

  Abstract

  The dynamics of air bubbles spreading on the underside of solid substrates is an important scientific problem with numerous applications. This work explores the spreading of bubbles against an ultra-thin, porous ultra-high-molecular-weight polyethylene (UHMWPE) film. This polymer film can be used in applications where a solid-liquid-gas interface is involved, like froth flotation for mineral processing, underwater methane capture, to prevent foaming in bioreactors, and in degassing in microfluidics. When an air bubble is released underneath such a film, the bubble bounces against the film, makes contact after the liquid film dewets, spreads against the film and shrinks in size as the gas within the bubble permeates through the pores of the film. In our work, these events were recorded using a high-speed camera. The effect of different surface-active species like surfactants, which exhibit interfacial mobility and proteins, which form a viscoelastic interfacial network, was also studied. The adsorption of these surface-active molecules led to profound differences in the interaction of the bubbles and their ultimate removal through the film. Importantly, the permeation flux of the bubbles was lower in the presence of these molecules, affected in part by a lower capillary driving force and also because of the decreased film permeability. This ultra-thin film offers a high permeation flux, which makes it a promising candidate for the aforementioned applications. Furthermore, the effect of surface-active species such as surfactants and proteins encountered in these environments is elucidated.

  View details for DOI 10.1016/j.jcis.2020.04.086

  View details for PubMedID 32387738

• Viscoelastic interfaces comprising of cellulose nanocrystals and lauroyl ethyl arginate for enhanced foam stability. Soft matter Czakaj, A., Kannan, A., Wisniewska, A., Grzes, G., Krzan, M., Warszynski, P., Fuller, G. G. 2020

  Abstract

  Stable aqueous foams composed of oppositely charged nanoparticles and surfactants have recently gained attention. We studied the draining of thin liquid films and the foam stability of aqueous mixtures of food grade cellulose nanocrystals (CNCs) and an oppositely charged surfactant - lauroyl ethyl arginate (LAE). Dynamic fluid film interferometry experiments with the bubble approaching the air/solution interface revealed a two-fold increase of the initial bubble film thickness and a maximum in drainage time at the optimal stoichiometry of LAE and CNC. The temporal evolution of the fluid film shape indicated a large contribution of structural forces to the film stability. The results of single liquid film drainage time and coalescence time experiments were partially correlated with bulk foam stability. With a further increase of LAE concentration, aggregation-induced foam destruction was observed. In the presence of a cationic surfactant, anisotropic and initially hydrophilic cellulose nanocrystals became partially hydrophobized and self-assembled at the interface. Cellulose nanocrystal shape anisotropy and wetting behaviour which have their origins in OH-exposed and buried crystalline planes are the sources of capillary interactions that promote CNC aggregation at planar and curved liquid/air interfaces. Dilatational and shear interfacial rheology experiments confirmed the formation of a highly elastic surfactant-nanoparticle interfacial layer. To the best of our knowledge, this is the first report on foaming properties for this system with fast adsorption kinetics influenced by CNC.

  View details for DOI 10.1039/c9sm02392e

  View details for PubMedID 32250379

• Mechanical and microstructural insights of Vibrio cholerae and Escherichia coli dual-species biofilm at the air-liquid interface. Colloids and surfaces. B, Biointerfaces Abriat, C., Enriquez, K., Virgilio, N., Cegelski, L., Fuller, G. G., Daigle, F., Heuzey, M. 2020; 188: 110786

  Abstract

  Biofilm is the dominant microbial form found in nature, in which bacterial species are embedded in a self-produced extracellular matrix (ECM). These complex microbial communities are responsible for several infections when they involve multispecies pathogenic bacteria. In previous studies, interfacial rheology proved to be a unique quantitative technique to follow in real-time the biofilm formation at the air-liquid interface. In this work, we studied a model system composed of two bacteria pathogenic capable of forming a pellicle biofilm, V. cholerae and E. coli. We used an integrated approach by combining a real-time quantitative analysis of the biofilm rheological properties, with the investigation of major matrix components and the pellicle microstructure. The results highlight the competition for the interface between the two species, driven by the biofilm formation growth rate. In the dual-species biofilm, the viscoelastic properties were dominated by V. cholera, which formed a mature biofilm 18 h faster than E. coli. The microstructure of the dual-species biofilm revealed a similar morphology to V. cholerae alone when both bacteria were initially added at the same amount. The analysis of some major ECM components showed that E. coli was not able to produce curli in the presence of V. cholerae, unless enough time was given for E. coli to colonize the air-liquid interface first. E. coli secreted phosphoethanolamine (pEtN) cellulose in the dual-species biofilm, but did not form a filamentous structure. Our pathogenic model system demonstrated the importance of the biofilm growth rate for multispecies biofilm composition at the air-liquid interface.

  View details for DOI 10.1016/j.colsurfb.2020.110786

  View details for PubMedID 31954270

• Perpendicular alignment of lymphatic endothelial cells in response to spatial gradients in wall shear stress. Communications biology Michalaki, E. n., Surya, V. N., Fuller, G. G., Dunn, A. R. 2020; 3 (1): 57

  Abstract

  One-way valves in the lymphatic system form from lymphatic endothelial cells (LECs) during embryonic development and are required for efficient tissue drainage. Although fluid flow is thought to guide both valve formation and maintenance, how this occurs at a mechanistic level remains incompletely understood. We built microfluidic devices that reproduce critical aspects of the fluid flow patterns found at sites of valvulogenesis. Using these devices, we observed that LECs replicated aspects of the early steps in valvulogenesis: cells oriented perpendicular to flow in the region of maximum wall shear stress (WSS) and exhibited enhanced nuclear localization of FOXC2, a transcription factor required for valvulogenesis. Further experiments revealed that the cell surface protein E-selectin was required for both of these responses. Our observations suggest that spatial gradients in WSS help to demarcate the locations of valve formation, and implicate E-selectin as a component of a mechanosensory process for detecting WSS gradients.

  View details for DOI 10.1038/s42003-019-0732-8

  View details for PubMedID 32029852

• Correction: Viscoelastic interfaces comprising of cellulose nanocrystals and lauroyl ethyl arginate for enhanced foam stability. Soft matter Czakaj, A. n., Kannan, A. n., Wiśniewska, A. n., Grześ, G. n., Krzan, M. n., Warszyński, P. n., Fuller, G. G. 2020

  Abstract

  Correction for 'Viscoelastic interfaces comprising of cellulose nanocrystals and lauroyl ethyl arginate for enhanced foam stability' by Agnieszka Czakaj et al., Soft Matter, 2020, 16, 3981-3990, DOI: 10.1039/C9SM02392E.

  View details for DOI 10.1039/d0sm90090g

  View details for PubMedID 32432604

• Evaporation-induced Rayleigh-Taylor instabilities in polymer solutions. Philosophical transactions. Series A, Mathematical, physical, and engineering sciences Mossige, E. J., Chandran Suja, V. n., Islamov, M. n., Wheeler, S. F., Fuller, G. G. 2020; 378 (2174): 20190533

  Abstract

  Understanding the mechanics of detrimental convective instabilities in drying polymer solutions is crucial in many applications such as the production of film coatings. It is well known that solvent evaporation in polymer solutions can lead to Rayleigh-Bénard or Marangoni-type instabilities. Here, we reveal another mechanism, namely that evaporation can cause the interface to display Rayleigh-Taylor instabilities due to the build-up of a dense layer at the air-liquid interface. We study experimentally the onset time (t p ) of the instability as a function of the macroscopic properties of aqueous polymer solutions, which we tune by varying the polymer concentration (c0), molecular weight and polymer type. In dilute solutions, t p shows two limiting behaviours depending on the polymer diffusivity. For high diffusivity polymers (low molecular weight), the pluming time scales as [Formula: see text]. This result agrees with previous studies on gravitational instabilities in miscible systems where diffusion stabilizes the system. On the other hand, in low diffusivity polymers the pluming time scales as [Formula: see text]. The stabilizing effect of an effective interfacial tension, similar to those in immiscible systems, explains this strong concentration dependence. Above a critical concentration, [Formula: see text], viscosity delays the growth of the instability, allowing time for diffusion to act as the dominant stabilizing mechanism. This results in t p scaling as (ν/c0)2/3. This article is part of the theme issue 'Stokes at 200 (Part 1)'.

  View details for DOI 10.1098/rsta.2019.0533

  View details for PubMedID 32507094

• Binding partner- and force-promoted changes in alphaE-catenin conformation probed by native cysteine labeling. Scientific reports Terekhova, K., Pokutta, S., Kee, Y. S., Li, J., Tajkhorshid, E., Fuller, G., Dunn, A. R., Weis, W. I. 2019; 9 (1): 15375

  Abstract

  Adherens Junctions (AJs) are cell-cell adhesion complexes that sense and propagate mechanical forces by coupling cadherins to the actin cytoskeleton via beta-catenin and the F-actin binding protein alphaE-catenin. When subjected to mechanical force, the cadherincatenin complex can tightly link to F-actin through alphaE-catenin, and also recruits the F-actin-binding protein vinculin. In this study, labeling of native cysteines combined with mass spectrometry revealed conformational changes in alphaE-catenin upon binding to the E-cadherinbeta-catenin complex, vinculin and F-actin. A method to apply physiologically meaningful forces in solution revealed force-induced conformational changes in alphaE-catenin when bound to F-actin. Comparisons of wild-type alphaE-catenin and a mutant with enhanced vinculin affinity using cysteine labeling and isothermal titration calorimetry provide evidence for allosteric coupling of the N-terminal beta-catenin-binding and the middle (M) vinculin-binding domain of alphaE-catenin. Cysteine labeling also revealed possible crosstalk between the actin-binding domain and the rest of the protein. The data provide insight into how binding partners and mechanical stress can regulate the conformation of full-length alphaE-catenin, and identify the M domain as a key transmitter of conformational changes.

  View details for DOI 10.1038/s41598-019-51816-3

  View details for PubMedID 31653927

• Mechanical Properties of Solidifying Assemblies of Nanoparticle Surfactants at the Oil-Water Interface. Langmuir : the ACS journal of surfaces and colloids Toor, A., Forth, J., Bochner de Araujo, S., Merola, M. C., Jiang, Y., Liu, X., Chai, Y., Hou, H., Ashby, P. D., Fuller, G. G., Russell, T. P. 2019

  Abstract

  The effect of polymer surfactant structure and concentration on the self-assembly, mechanical properties, and solidification of nanoparticle surfactants (NPSs) at the oil-water interface was studied. The surface tension of the oil-water interface was found to depend strongly on the choice of the polymer surfactant used to assemble the NPSs, with polymer surfactants bearing multiple polar groups being the most effective at reducing interfacial tension and driving the NPS assembly. By contrast, only small variations in the shear modulus of the system were observed, suggesting that it is determined largely by particle density. In the presence of polymer surfactants bearing multiple functional groups, NPS assemblies on pendant drop surfaces were observed to spontaneously solidify above a critical polymer surfactant concentration. Interfacial solidification accelerated rapidly as polymer surfactant concentration was increased. On long timescales after solidification, pendant drop interfaces were observed to spontaneously wrinkle at sufficiently low surface tensions (approximately 5 mN m-1). Interfacial shear rheology of the NPS assemblies was elastic-dominated, with the shear modulus ranging from 0.1 to 1 N m-1, comparable to values obtained for nanoparticle monolayers elsewhere. Our work paves the way for the development of designer, multicomponent oil-water interfaces with well-defined mechanical, structural, and functional properties.

  View details for DOI 10.1021/acs.langmuir.9b01575

  View details for PubMedID 31536356

• Linking aggregation and interfacial properties in monoclonal antibody-surfactant formulations JOURNAL OF COLLOID AND INTERFACE SCIENCE Kannan, A., Shieh, I. C., Fuller, G. G. 2019; 550: 128–38

  View details for DOI 10.1016/j.jcis.2019.04.060

  View details for Web of Science ID 000469902400013

• Spreading of rinsing liquids across a horizontal rotating substrate PHYSICAL REVIEW FLUIDS Walls, D. J., Ylitalo, A. S., Mui, D. L., Frostad, J. M., Fuller, G. G. 2019; 4 (8)

  View details for DOI 10.1103/PhysRevFluids.4.084102

  View details for Web of Science ID 000479035500002

• The influence of protein deposition on contact lens tear film stability COLLOIDS AND SURFACES B-BIOINTERFACES Rabiah, N. I., Scales, C. W., Fuller, G. G. 2019; 180: 229–36

  View details for DOI 10.1016/j.colsurfb.2019.04.051

  View details for Web of Science ID 000474501900026

• Evolution of rivulets during spreading of an impinging water jet on a rotating, precoated substrate Ylitalo, A. S., Walls, D. J., Mui, D. L., Frostad, J. M., Fuller, G. G. AMER INST PHYSICS. 2019

  View details for DOI 10.1063/1.5109806

  View details for Web of Science ID 000483888900047

• The influence of protein deposition on contact lens tear film stability. Colloids and surfaces. B, Biointerfaces Rabiah, N. I., Scales, C. W., Fuller, G. G. 2019; 180: 229–36

  Abstract

  When contact lenses (CLs) are worn, they are subject to deposition of the surrounding biomolecules found in the tear film (TF) of the eye. There is a correlation between protein deposition on CLs and feelings of discomfort in patients, but it has not been well understood if these feelings of discomfort arise solely from immunogenic reactions to the protein deposits or a physical instability of the tear film on protein-fouled CLs. This study compared two hydrogel CLs: etafilcon A (polyhydroxyethylmethacrylate-based hydrogel) and senofilcon A (silicone hydrogel with internal wetting agent) to elucidate how lysozyme and mucin sorption affect the wettability of CLs and understand the potential impact on TF stability in vivo. Here, we use "wettability" to refer to the stability of a film of phosphate buffered saline on the CL surface. A custom-built platform was used to conduct experiments that monitored the stability of phosphate-buffered saline (PBS) and artificial tear solution (ATS) on clean and fouled CLs. PBS was more stable (wettable) on etafilcon A than senofilcon A, and both CLs showed increased wettability after protein-fouling. However, surface wettability in PBS did not correlate with the stability of ATS on the CLs. The viscoelastic interface of ATS slowed drainage, making evaporation the primary thinning factor, in addition to the presence of a disjoining pressure that stabilized the thin film. From this, we conclude that protein deposition increases CL wettability, but does not alter tear film stability and we predict that CL susceptibility to evaporation is a better predictor of TF stability than wettability.

  View details for PubMedID 31054463

• Linking aggregation and interfacial properties in monoclonal antibody-surfactant formulations. Journal of colloid and interface science Kannan, A., Shieh, I. C., Fuller, G. G. 2019; 550: 128–38

  Abstract

  Monoclonal antibodies (mAbs) are therapeutic proteins used in the treatment of many diseases due to their specificity in binding targets. Aggregation of these molecules is a major challenge in their formulation development. MAbs spontaneously adsorb onto air-solution interfaces and experience interfacial stresses, which is one of the major causes of aggregation. This work studies the effect of pharmaceutically relevant surfactants like polysorbate-20, poloxamer-188 and polyethylene glycol in controlling the aggregation and interfacial behavior of a mAb prone to interfacial aggregation. Agitation-induced aggregation was characterized using size-exclusion chromatography, flow cytometry and light obscuration. The addition of surfactants reduced the formation of aggregates. In the presence of surfactants competitively adsorbing to the interface, the number of soluble aggregates (size < 100 nm) depended on the amount of mAb adsorbed. On the other hand, the number of insoluble aggregates was governed not by the surface concentration, but by the ability of the adsorbed mAbs to interact and form a cohesive network. To correlate the aggregation in these mAb-surfactant mixtures with their interfacial behavior, studies on the drainage of a fluid film sandwiched between two mAb-surfactant laden interfaces were performed. The amount of fluid entrained depended on different governing mechanisms - interfacial rheology, surface tension and surface tension gradients for different surfactants. The surface tension gradients further resulted in an instability and local thickening in the sandwiched fluid film, which was affected by the presence of mAbs. Understanding the aggregation propensities of different mAb-surfactant mixtures and linking them to the interfacial behavior will greatly aid in understanding the aggregation mechanism and in mitigating aggregate formation by optimizing surfactant type and concentration in the formulation.

  View details for PubMedID 31055138

• Lymphatic endothelial cell calcium pulses are sensitive to spatial gradients in wall shear stress MOLECULAR BIOLOGY OF THE CELL Surya, V. N., Michalaki, E., Fuller, G. G., Dunn, A. R. 2019; 30 (7): 923–31

  View details for DOI 10.1091/mbc.E18-10-0618

  View details for Web of Science ID 000461869400011

• Evaporation-driven solutocapillary flow of thin liquid films over curved substrates PHYSICAL REVIEW FLUIDS Rodriguez-Hakim, M., Barakat, J. M., Shi, X., Shaqfeh, E. G., Fuller, G. G. 2019; 4 (3)

  View details for DOI 10.1103/PhysRevFluids.4.034002

  View details for Web of Science ID 000461075500001

• Lymphatic endothelial cell calcium pulses are sensitive to spatial gradients in wall shear stress. Molecular biology of the cell Surya, V. N., Michalaki, E., Fuller, G. G., Dunn, A. R. 2019: mbcE18100618

  Abstract

  Cytosolic calcium (Ca2+) is a ubiquitous second messenger that influences numerous aspects of cellular function. In many cell types cytosolic Ca2+ concentrations are characterized by periodic pulses whose dynamics can influence downstream signal transduction. Here, we examined the general question of how cells use Ca2+ pulses to encode input stimuli in the context of the response of lymphatic endothelial cells (LECs) to fluid flow. Previous work shows that fluid flow regulates Ca2+ dynamics in LECs, and that Ca2+-dependent signaling plays a key role in regulating lymphatic valve formation during embryonic development. However, how fluid flow might influence the Ca2+ pulse dynamics of individual LECs remained, to our knowledge, little explored. We used live-cell imaging to characterize Ca2+ pulse dynamics in LECs exposed to fluid flow in an in vitro flow device that generates spatial gradients in wall shear stress (WSS) such as are found at sites of valve formation. We found that the frequency of Ca2+ pulses was sensitive to the magnitude of WSS, while the duration of individual Ca2+ pulses increased in the presence of spatial gradients in WSS. These observations reveal an example of how cells can separately modulate Ca2+ pulse frequency and duration to encode distinct forms of information, a phenomenon that could extend to other cell types. Movie S1 Movie S1 HLMVEC Ca2+ dynamics in the IFC, recorded for 30 minutes starting from the onset of flow at t = 50 s. Regions corresponding to Rings 1 and 2 are shown, which have average WSSs of 32 and 65 dyn/cm2, respectively. The flow direction is radially outward and symmetric about the jet center at the center of Ring 1. Frames were recorded every 5 seconds. Scale bar, 100 mum. Movie S2 Movie S2 HLMVEC Ca2+ dynamics as in Movie 1 for Rings 2 - 6, which have average WSSs of 65, 53, 30, 17 and 11 dyn/cm2. The flow direction is radially outward and here is roughly from left to right. Frames were recorded every 5 seconds. Scale bar, 100 mum. Movie S3 Movie S3 HLMVEC Ca2+ dynamics for cells exposed to uniform WSS (parallel plate flow), recorded for 30 minutes from the onset of flow at t = 50 s. Here, all HLMVECs experience a WSS of 50 dyn/cm2. The flow direction is from the bottom of the video to the top. Frames were recorded every 5 seconds. Scale bar, 100 mum. Movie S4 Movie S4 HLMVEC Ca2+ dynamics under no flow conditions, recorded for 30 minutes. Frames were recorded every 5 seconds. Scale bar, 100 mum.

  View details for PubMedID 30811261

• Carbon compositional analysis of hydrogel contact lenses by solid-state NMR spectroscopy. Solid state nuclear magnetic resonance Rabiah, N. I., Romaniuk, J. A., Fuller, G. G., Scales, C. W., Cegelski, L. n. 2019; 102: 47–52

  Abstract

  Contact lenses are worn by over 140 million people each year and tremendous research and development efforts contribute to the identification and selection of hydrogel components and production protocols to yield lenses optimized for chemical and physiological properties, eye health and comfort. The final molecular composition and extent of incorporation of different components in contact lenses is routinely estimated after lens production through the analysis of the soluble components that were not included in the lens, i.e. remaining starting materials. Examination of composition in the actual intact materials is always valued and can reveal details that are missed by only examining the non-incorporated components, for example identifying chemical changes to components in lenses during the production process. Solid-state nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for the direct compositional analysis of insoluble and heterogeneous materials and is also uniquely suited to determining parameters of architecture in contact lenses. We utilized 13C cross-polarization magic angle spinning (CPMAS) NMR to examine and compare the carbon composition of soft contact lenses. 13C NMR spectra of individual polymer components enabled the determination of the approximate molecular carbon contributions of major lens components. Comparisons of the conventional etafilcon A hydrogel (1 Day Acuvue MOIST) lenses and silicone hydrogel lenses (Acuvue Oasys, Dailies Total 1, Clariti 1 Day, Biofinity, and Pure Vision) revealed major spectral differences, with considerable variation even among different silicone hydrogel lenses. The solid-state NMR approach provides a direct spectral reporting of carbon types in the hydrogel lens itself. This approach represents a valuable complementary analysis to benefit contact lens research and development and could be extended to isotopically labeled hydrogel lenses to map proximities and architecture between hydrogel components.

  View details for DOI 10.1016/j.ssnmr.2019.07.003

  View details for PubMedID 31376631

• Unraveling Escherichia coli's Cloak: Identification of Phosphoethanolamine Cellulose, Its Functions, and Applications. Microbiology insights Jeffries, J. n., Fuller, G. G., Cegelski, L. n. 2019; 12: 1178636119865234

  Abstract

  Bacterial biofilms are complex, multicellular communities made up of bacteria enmeshed in a self-produced extracellular matrix (ECM) that protects against environmental stress. The ECM often comprises insoluble components, which complicates the study of biofilm composition, structure, and function. Wrinkled, agar-grown Escherichia coli biofilms require 2 insoluble macromolecules: curli amyloid fibers and cellulosic polymers. We quantified these components with solid-state nuclear magnetic resonance (NMR) and determined that curli contributed 85% of the isolated uropathogenic E coli ECM dry mass. The remaining 15% was cellulosic, but, surprisingly, was not ordinary cellulose. We tracked the identity of the unanticipated peak in the 13C NMR spectrum of the cellulosic component and discovered that E coli secrete phosphoethanolamine (pEtN)-modified cellulose. Cellulose is the most abundant biopolymer on the planet, and this marked the first identification of a naturally, chemically modified cellulose. To investigate potential roles of pEtN cellulose, we customized a newly designed live-cell monolayer rheometer and demonstrated that pEtN cellulose facilitated E coli attachment to bladder epithelial cells and acted as a glue, keeping curli cell associated. The discovery of pEtN cellulose opens questions regarding its biological function(s) and provides opportunities in materials science to explore this newly discovered biopolymer.

  View details for DOI 10.1177/1178636119865234

  View details for PubMedID 31431800

  View details for PubMedCentralID PMC6685106

• Influence of interfacial elasticity on liquid entrainment in thin foam films PHYSICAL REVIEW FLUIDS Lin, G., Frostad, J. M., Fuller, G. G. 2018; 3 (11)

  View details for DOI 10.1103/PhysRevFluids.3.114001

  View details for Web of Science ID 000449312900002

• Phosphoethanolamine cellulose enhances curli-mediated adhesion of uropathogenic Escherichia coli to bladder epithelial cells PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Hollenbeck, E. C., Antonoplis, A., Chai, C., Thongsomboon, W., Fuller, G. G., Cegelski, L. 2018; 115 (40): 10106-10111

  View details for DOI 10.1073/pnas.1801564115

  View details for Web of Science ID 000446078700080

• Phosphoethanolamine cellulose enhances curli-mediated adhesion of uropathogenic Escherichia coli to bladder epithelial cells. Proceedings of the National Academy of Sciences of the United States of America Hollenbeck, E. C., Antonoplis, A., Chai, C., Thongsomboon, W., Fuller, G. G., Cegelski, L. 2018

  Abstract

  Uropathogenic Escherichia coli (UPEC) are the major causative agents of urinary tract infections, employing numerous molecular strategies to contribute to adhesion, colonization, and persistence in the bladder niche. Identifying strategies to prevent adhesion and colonization is a promising approach to inhibit bacterial pathogenesis and to help preserve the efficacy of available antibiotics. This approach requires an improved understanding of the molecular determinants of adhesion to the bladder urothelium. We designed experiments using a custom-built live cell monolayer rheometer (LCMR) to quantitatively measure individual and combined contributions of bacterial cell surface structures [type 1 pili, curli, and phosphoethanolamine (pEtN) cellulose] to bladder cell adhesion. Using the UPEC strain UTI89, isogenic mutants, and controlled conditions for the differential production of cell surface structures, we discovered that curli can promote stronger adhesive interactions with bladder cells than type 1 pili. Moreover, the coproduction of curli and pEtN cellulose enhanced adhesion. The LCMR enables the evaluation of adhesion under high-shear conditions to reveal this role for pEtN cellulose which escaped detection using conventional tissue culture adhesion assays. Together with complementary biochemical experiments, the results support a model wherein cellulose serves a mortar-like function to promote curli association with and around the bacterial cell surface, resulting in increased bacterial adhesion strength at the bladder cell surface.

  View details for PubMedID 30232265

• The shape evolution of liquid droplets in miscible environments JOURNAL OF FLUID MECHANICS Walls, D. J., Meiburg, E., Fuller, G. G. 2018; 852: 422–52

  View details for DOI 10.1017/jfm.2018.535

  View details for Web of Science ID 000440937600002

• Crosslink density influences the adhesive strength of silicone hydrogel surfaces against corneal epithelial cells Liu, C., Scales, C. W., Fuller, G. G. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2018

  View details for Web of Science ID 000442912505075

• Influence of tear-film component integration on contact lens wettability Rabiah, N. I., Scales, C. W., Fuller, G. G. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2018

  View details for Web of Science ID 000442932802102

• Coalescence and spontaneous emulsification in the presence of asphaltenes Fuller, G., Bochner, S., Merola, M., Vlassopoulos, D. AMER CHEMICAL SOC. 2018

  View details for Web of Science ID 000435537706193

• Adhesion and viscoelasticity of living tissues: The live cell monolayer rheometer (LCMR) Fuller, G., Pokki, J., Merola, M., Undieh, A., Hollenbeck, E., Cegelski, L. AMER CHEMICAL SOC. 2018

  View details for Web of Science ID 000435537705661

• Monoclonal Antibody Interfaces: Dilatation Mechanics and Bubble Coalescence LANGMUIR Kannan, A., Shieh, I. C., Leiske, D. L., Fuller, G. G. 2018; 34 (2): 630–38

  Abstract

  Monoclonal antibodies (mAbs) are proteins that uniquely identify targets within the body, making them well-suited for therapeutic applications. However, these amphiphilic molecules readily adsorb onto air-solution interfaces where they tend to aggregate. We investigated two mAbs with different propensities to aggregate at air-solution interfaces. The understanding of the interfacial rheological behavior of the two mAbs is crucial in determining their aggregation tendency. In this work, we performed interfacial stress relaxation studies under compressive step strain using a custom-built dilatational rheometer. The dilatational relaxation modulus was determined for these viscoelastic interfaces. The initial value and the equilibrated value of relaxation modulus were larger in magnitude for the mAb with a higher tendency to aggregate in response to interfacial stress. We also performed single-bubble coalescence experiments using a custom-built dynamic fluid-film interferometer (DFI). The bubble coalescence times also correlated to the mAbs aggregation propensity and interfacial viscoelasticity. To study the influence of surfactants in mAb formulations, polyethylene glycol (PEG) was chosen as a model surfactant. In the mixed mAb/PEG system, we observed that the higher aggregating mAb coadsorbed with PEG and formed domains at the interface. In contrast, for the other mAb, PEG entirely covered the interface at the concentrations studied. We studied the mobility of the interfaces, which was manifested by the presence or the lack of Marangoni stresses. These dynamics were strongly correlated with the interfacial viscoelasticity of the mAbs. The influence of competitive destabilization in affecting the bubble coalescence times for the mixed mAb/PEG systems was also studied.

  View details for PubMedID 29251942

• Droplet Coalescence and Spontaneous Emulsification in the Presence of Asphaltene Adsorption LANGMUIR de Araujo, S., Merola, M., Vlassopoulos, D., Fuller, G. G. 2017; 33 (40): 10501–10

  Abstract

  In a refinery, undesired high levels of salt concentration in crude oils are reduced by the contact of water with crude oils, where an emulsion is formed. Later, the separation of the water from the desalted oil is essential for the quality of both wastewater discharge and refined oil. However, complex components of crude oils such as asphaltenes may stabilize these emulsions, causing difficulties in efficient separation. Here, we show the coalescence inhibition caused by asphaltene adsorption for both water-in-oil and oil-in-water emulsions, where the oil phase consists of a simple model of asphaltenes dissolved in toluene. We find that oil-in-water emulsions are less stable than water-in-oil emulsions by using a newly developed instrument where controlled experiments can be performed to measure the coalescence time of a single droplet against an oil/water interface as a function of asphaltene aging (associated with the adsorption process of asphaltene molecules onto the interfaces) and asphaltene concentration. Furthermore, we find that the coalescence time for water droplets exhibits a maximum because of a spontaneous emulsification at the oil/water interface that produces droplets consisting of asphaltene-laden water droplets.

  View details for PubMedID 28889742

• DACH1 stimulates shear stress-guided endothelial cell migration and coronary artery growth through the CXCL12-CXCR4 signaling axis GENES & DEVELOPMENT Chang, A. H., Raftrey, B. C., D'Amato, G., Surya, V. N., Poduri, A., Chen, H. I., Goldstone, A. B., Woo, J., Fuller, G. G., Dunn, A. R., Red-Horse, K. 2017; 31 (13): 1308–24

  Abstract

  Sufficient blood flow to tissues relies on arterial blood vessels, but the mechanisms regulating their development are poorly understood. Many arteries, including coronary arteries of the heart, form through remodeling of an immature vascular plexus in a process triggered and shaped by blood flow. However, little is known about how cues from fluid shear stress are translated into responses that pattern artery development. Here, we show that mice lacking endothelial Dach1 had small coronary arteries, decreased endothelial cell polarization, and reduced expression of the chemokine Cxcl12 Under shear stress in culture, Dach1 overexpression stimulated endothelial cell polarization and migration against flow, which was reversed upon CXCL12/CXCR4 inhibition. In vivo, DACH1 was expressed during early arteriogenesis but was down in mature arteries. Mature artery-type shear stress (high, uniform laminar) specifically down-regulated DACH1, while the remodeling artery-type flow (low, variable) maintained DACH1 expression. Together, our data support a model in which DACH1 stimulates coronary artery growth by activating Cxcl12 expression and endothelial cell migration against blood flow into developing arteries. This activity is suppressed once arteries reach a mature morphology and acquire high, laminar flow that down-regulates DACH1. Thus, we identified a mechanism by which blood flow quality balances artery growth and maturation.

  View details for PubMedID 28779009

• Interfacial mechanisms for stability of surfactant-laden films PLOS ONE Bhamla, M. S., Chai, C., Alvarez-Valenzuela, M. A., Tajuelo, J., Fuller, G. G. 2017; 12 (5)

  Abstract

  Thin liquid films are central to everyday life. They are ubiquitous in modern technology (pharmaceuticals, coatings), consumer products (foams, emulsions) and also serve vital biological functions (tear film of the eye, pulmonary surfactants in the lung). A common feature in all these examples is the presence of surface-active molecules at the air-liquid interface. Though they form only molecular-thin layers, these surfactants produce complex surface stresses on the free surface, which have important consequences for the dynamics and stability of the underlying thin liquid film. Here we conduct simple thinning experiments to explore the fundamental mechanisms that allow the surfactant molecules to slow the gravity-driven drainage of the underlying film. We present a simple model that works for both soluble and insoluble surfactant systems in the limit of negligible adsorption-desorption dynamics. We show that surfactants with finite surface rheology influence bulk flow through viscoelastic interfacial stresses, while surfactants with inviscid surfaces achieve stability through opposing surface-tension induced Marangoni flows.

  View details for DOI 10.1371/journal.pone.0175753

  View details for Web of Science ID 000401487700007

  View details for PubMedID 28520734

• Temperature controlled tensiometry using droplet microfluidics LAB ON A CHIP Lee, D., Fang, C., Ravan, A. S., Fuller, G. G., Shen, A. Q. 2017; 17 (4): 717-726

  Abstract

  We develop a temperature controllable microfluidic device for the accurate measurement of temperature dependent interfacial tensions between two immiscible liquids. A localized temperature control system is integrated with the microfluidic platform to maintain an accurate temperature inside the device. The temperature uniformity and sensitivity are verified by both simulation and experimental results. Temperature dependent interfacial tensions are measured dynamically and rapidly, relying on quantitative analysis of the deformation and retraction dynamics of droplets under extensional flow. Our microfluidic tensiometry offers the capability of measuring temperature dependent interfacial tensions with precise and systematic temperature control in the range of room temperature to 70 °C, which is valuable for studying transient interfacial dynamics, interfacial reactions, and the surfactant adsorption process.

  View details for DOI 10.1039/c6lc01384h

  View details for Web of Science ID 000395892500015

  View details for PubMedID 28154859

• Sphingosine 1-phosphate receptor 1 regulates the directional migration of lymphatic endothelial cells in response to fluid shear stress JOURNAL OF THE ROYAL SOCIETY INTERFACE Surya, V. N., Michalaki, E., Huang, E. Y., Fuller, G. G., Dunn, A. R. 2016; 13 (125)

  Abstract

  The endothelial cells that line blood and lymphatic vessels undergo complex, collective migration and rearrangement processes during embryonic development, and are known to be exquisitely responsive to fluid flow. At present, the molecular mechanisms by which endothelial cells sense fluid flow remain incompletely understood. Here, we report that both the G-protein-coupled receptor sphingosine 1-phosphate receptor 1 (S1PR1) and its ligand sphingosine 1-phosphate (S1P) are required for collective upstream migration of human lymphatic microvascular endothelial cells in an in vitro setting. These findings are consistent with a model in which signalling via S1P and S1PR1 are integral components in the response of lymphatic endothelial cells to the stimulus provided by fluid flow.

  View details for DOI 10.1098/rsif.2016.0823

  View details for Web of Science ID 000391108100013

  View details for PubMedID 27974574

  View details for PubMedCentralID PMC5221531

• Impact of Compressibility on the Control of Bubble-Pressure Tensiometers LANGMUIR Suja, V. C., Frostad, J. M., Fuller, G. G. 2016; 32 (46): 12031-12038

  View details for DOI 10.1021/acs.langmuir.6b03258

  View details for Web of Science ID 000388914400005

• Dynamic fluid-film interferometry as a predictor of bulk foam properties. Soft matter Frostad, J. M., Tammaro, D., Santollani, L., Bochner de Araujo, S., Fuller, G. G. 2016: -?

  Abstract

  Understanding and enabling the control of the properties of foams is important for a variety of commercial processes and consumer products. In these systems, the role of surface active compounds has been the subject of many investigations using a wide range of techniques. The study of their influence on simplified geometries such as two bubbles in a liquid or a thin film of solution (such as in the well-known Scheludko cell), has yielded important fundamental understanding. Similarly, in this work an interferometric technique is used to study the dynamic evolution of the film formed by a single bubble being pressed against a planar air-liquid interface. Here interferometry is used to dynamically measure the total volume of liquid contained within the thin-film region between the bubble and the planar interface. Three different small-molecule, surfactant solutions were investigated and the data obtained via interferometry were compared to measurements of the density of bulk foams of the same solutions. The density measurements were collected with a simple, but novel technique using a conical-shaped bubbling apparatus. The results reveal a strong correlation between the measurements on single bubbles and complete foams. This suggests that further investigations using interferometric techniques can be instrumental to building a more detailed mechanistic understanding of how different surface-active compounds influence foam properties. The results also reveal that the commonly used assumption that surfactant-laden interfaces may be modeled as immobile, is too simplistic to accurately model interfaces with small-molecule surfactants.

  View details for PubMedID 27752701

• Placing Marangoni instabilities under arrest PHYSICAL REVIEW FLUIDS Bhamla, M. S., Fuller, G. G. 2016; 1 (5)

  View details for DOI 10.1103/PhysRevFluids.1.050506

  View details for Web of Science ID 000390230600007

• Mechanical Behavior of a Bacillus subtilis Pellicle JOURNAL OF PHYSICAL CHEMISTRY B Hollenbeck, E. C., Douarche, C., Allain, J., Roger, P., Regeard, C., Cegelski, L., Fuller, G. G., Raspaud, E. 2016; 120 (26): 6080-6088

  Abstract

  Bacterial biofilms consist of a complex network of biopolymers embedded with microorganisms, and together these components form a physically robust structure that enables bacteria to grow in a protected environment. This structure can help unwanted biofilms persist in situations ranging from chronic infection to the biofouling of industrial equipment, but under certain circumstances it can allow the biofilm to disperse and colonize new niches. Mechanical properties are therefore a key aspect of biofilm life. In light of the recently discovered growth-induced compressive stress present within a biofilm, we studied the mechanical behavior of Bacillus subtilis pellicles, or biofilms at the air-liquid interface, and tracked simultaneously the force response and macroscopic structural changes during elongational deformations. We observed that pellicles behaved viscoelastically in response to small deformations, such that the growth-induced compressive stress was still present, and viscoplastically at large deformations, when the pellicles were under tension. In addition, by using particle imaging velocimetry we found that the pellicle deformations were nonaffine, indicating heterogeneous mechanical properties with the pellicle being more pliable near attachment surfaces. Overall, our results indicate that we must consider not only the viscoelastic but also the viscoplastic and mechanically heterogeneous nature of these structures to understand biofilm dispersal and removal.

  View details for DOI 10.1021/acs.jpcb.6b02074

  View details for Web of Science ID 000379457200033

  View details for PubMedID 27046510

• Multiplexed Fluid Flow Device to Study Cellular Response to Tunable Shear Stress Gradients ANNALS OF BIOMEDICAL ENGINEERING Ostrowski, M. A., Huang, E. Y., Surya, V. N., Poplawski, C., Barakat, J. M., Lin, G. L., Fuller, G. G., Dunn, A. R. 2016; 44 (7): 2261-2272

  Abstract

  Endothelial cells (ECs) line the interior of blood and lymphatic vessels and experience spatially varying wall shear stress (WSS) as an intrinsic part of their physiological function. How ECs, and mammalian cells generally, sense spatially varying WSS remains poorly understood, due in part to a lack of convenient tools for exposing cells to spatially varying flow patterns. We built a multiplexed device, termed a 6-well impinging flow chamber, that imparts controlled WSS gradients to a six-well tissue culture plate. Using this device, we investigated the migratory response of lymphatic microvascular ECs, umbilical vein ECs, primary fibroblasts, and epithelial cells to WSS gradients on hours to days timescales. We observed that lymphatic microvascular ECs migrate upstream, against the direction of flow, a response that was unique among all the cells types investigated here. Time-lapse, live cell imaging revealed that the microtubule organizing center relocated to the upstream side of the nucleus in response to the applied WSS gradient. To further demonstrate the utility of our device, we screened for the involvement of canonical signaling pathways in mediating this upstream migratory response. These data highlight the importance of WSS magnitude and WSS spatial gradients in dictating the cellular response to fluid flow.

  View details for DOI 10.1007/s10439-015-1500-7

  View details for Web of Science ID 000377437600015

  View details for PubMedID 26589597

  View details for PubMedCentralID PMC4874920

• Interfacial Rheology of Hydrogen-Bonded Polymer Multilayers Assembled at Liquid Interfaces: Influence of Anchoring Energy and Hydrophobic Interactions LANGMUIR Le Tirilly, S., Tregouet, C., Reyssat, M., Bone, S., Geffroy, C., Fuller, G., Pantoustier, N., Perrin, P., Monteux, C. 2016; 32 (24): 6089-6096

  Abstract

  We study the 2D rheological properties of hydrogen-bonded polymer multilayers assembled directly at dodecane-water and air-water interfaces using pendant drop/bubble dilation and the double-wall ring method for interfacial shear. We use poly(vinylpyrrolidone) (PVP) as a proton acceptor and a series of polyacrylic acids as proton donors. The PAA series of chains with varying hydrophobicity was fashioned from poly(acrylic acid), (PAA), polymethacrylic acid (PMAA), and a homemade hydrophobically modified polymer. The latter consisted of a PAA backbone covalently grafted with C12 moieties at 1% mol (referred to as PAA-1C12). Replacing PAA with the more hydrophobic PMAA provides a route for combining hydrogen bonding and hydrophobic interactions to increase the strength and/or the number of links connecting the polyacid chains to PVP. This systematic replacement allows for control of the ability of the monomer units inside the absorbed polymer layer to reorganize as the interface is sheared or compressed. Consequently, the interplay of hydrogen bonding and hydrophobic interactions leads to control of the resistance of the polymer multilayers to both shear and dilation. Using PAA-1C12 as the first layer improves the anchoring energy of a few monomers of the chain without changing the strength of the monomer-monomer contact in the complex layer. In this way, the layer does not resist shear but resists compression. This strategy provides the means for using hydrophobicity to control the interfacial dynamics of the complexes adsorbed at the interface of the bubbles and droplets that either elongate or buckle upon compression. Moreover, we demonstrate the pH responsiveness of these interfacial multilayers by adding aliquots of NaOH to the acidic water subphase surrounding the bubbles and droplets. Subsequent pH changes can eventually break the polymer complex, providing opportunities for encapsulation/release applications.

  View details for DOI 10.1021/acs.langmuir.6b01054

  View details for Web of Science ID 000378470000010

  View details for PubMedID 27176147

• Spreading of miscible liquids PHYSICAL REVIEW FLUIDS Walls, D. J., Haward, S. J., Shen, A. Q., Fuller, G. G. 2016; 1 (1)

  View details for DOI 10.1103/PhysRevFluids.1.013904

  View details for Web of Science ID 000390193300001

• Growth Kinetics and Mechanics of Hydrate Films by Interfacial Rheology LANGMUIR Leopercio, B. C., de Souza Mendes, P. R., Fuller, G. G. 2016; 32 (17): 4203-4209

  Abstract

  A new approach to study and understand the kinetics and mechanical properties of hydrates by interfacial rheology is presented. This is made possible using a "double wall ring" interfacial rheology cell that has been designed to provide the necessary temperature control. Cyclopentane and water are used to form hydrates, and this model system forms these structures at ambient pressures. Different temperature and water/hydrocarbon contact protocols are explored. Of particular interest is the importance of first contacting the hydrocarbon against ice crystals in order to initiate hydrate formation. Indeed, this is found to be the case, even though the hydrates may be created at temperatures above the melting point of ice. Once hydrates completely populate the hydrocarbon/water interface, strain sweeps of the interfacial elastic and viscous moduli are conducted to interrogate the mechanical response and fragility of the hydrate films. The dependence on temperature, Tf, by the kinetics of formation and the mechanical properties is reported, and the cyclopentane hydrate dissociation temperature was found to be between 6 and 7 °C. The formation time (measured from the moment when cyclopentane first contacts ice crystals) as well as the elastic modulus and the yield strain increase as Tf increases.

  View details for DOI 10.1021/acs.langmuir.6b00703

  View details for Web of Science ID 000375520800009

  View details for PubMedID 27076092

• Nonmonotonic Elasticity of the Crude Oil-Brine Interface in Relation to Improved Oil Recovery LANGMUIR Chavez-Miyauchi, T. E., Firoozabadi, A., Fuller, G. G. 2016; 32 (9): 2192-2198

  Abstract

  Injection of optimized chemistry water in enhanced oil recovery (EOR) has gained much interest in the past few years. Crude oil-water interfaces can have a viscoelastic character affected by the adsorption of amphiphilic molecules. The brine concentration as well as surfactants may strongly affect the fluid-fluid interfacial viscoelasticity. In this work we investigate interfacial viscoelasticity of two different oils in terms of brine concentration and a nonionic surfactant. We correlate these measurements with oil recovery in a glass-etched flow microchannel. Interfacial viscoelasticity develops relatively fast in both oils, stabilizing at about 48 h. The interfaces are found to be more elastic than viscous. The interfacial elastic (G') and viscous (G″) moduli increase as the salt concentration decreases until a maximum in viscoelasticity is observed around 0.01 wt % of salt. Monovalent (Na(+)) and divalent (Mg(2+)) cations are used to investigate the effect of ion type; no difference is observed at low salinity. The introduction of a small amount of a surfactant (100 ppm) increases the elasticity of the crude oil-water interface at high salt concentration. Aqueous solutions that give the maximum interface viscoelasticity and high salinity brines are used to displace oil in a glass-etched "porous media" micromodel. Pressure fluctuations after breakthrough are observed in systems with high salt concentration while at low salt concentration there are no appreciable pressure fluctuations. Oil recovery increases by 5-10% in low salinity brines. By using a small amount of a nonionic surfactant with high salinity brine, oil recovery is enhanced 10% with no pressure fluctuations. Interface elasticity reduces the snap-off of the oil phase, leading to reduced pressure fluctuations. This study sheds light on significance of interface viscoelasticity in oil recovery by change in salt concentration and by addition of a small amount of a nonionic surfactant.

  View details for DOI 10.1021/acs.langmuir.5b04354

  View details for Web of Science ID 000371851400006

  View details for PubMedID 26840555

• Instability and Breakup of Model Tear Films INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE Bhamla, M. S., Chai, C., Rabiah, N. I., Frostad, J. M., Fuller, G. G. 2016; 57 (3): 949-958

  Abstract

  An experimental platform to replicate the human tear film on a contact lens is presented. The influence of interfacial viscoelasticity in stabilizing in vitro model tear films against breakup and dewetting is investigated using this instrument.Model tear films consisting of bovine meibomian lipids (meibum) spread on either PBS or artificial tear solution (ATS) are created. The interfacial shear rheology of these films is measured as a function of temperature. The dewetting dynamics of these films is then investigated using the Interfacial Dewetting and Drainage Optical Platform (i-DDrOP) on top of silicone hydrogel (SiHy) contact lenses at 23 and 35°C. The film breakup times are evaluated using two parameters: onset of film breakup, Tonset for thick films (∼100 μm), and tear breakup times, TBU for thin films (∼1 μm). Thin film thinning rates as a result of evaporation are also calculated.The ATS/meibum films have the largest surface rheology and correspondingly show the largest Tonset times at both 23 and 35°C. The parameter TBU is also significantly larger for ATS/meibum (TBU ∼ 40 seconds) compared with that of ATS and PBS/meibum films (TBU ∼ 30 seconds) at room temperature. However, at 35°C, all three model tear films exhibit similar TBU ∼ 17 seconds and average rate of thinning of -4 μm/minute.Tear film stability is influenced by both surface rheology and evaporation. The in vitro tear breakup times and thinning rates of model tear films at 35°C are in good agreement with in vivo measurements previously reported, highlighting the utility of the i-DDrOP for in vitro tear film breakup research.

  View details for DOI 10.1167/iovs.15-18064

  View details for Web of Science ID 000374860600026

  View details for PubMedID 26943158

• Nanoscale Patterning of Extracellular Matrix Alters Endothelial Function under Shear Stress. Nano letters Nakayama, K. H., Surya, V. N., Gole, M., Walker, T. W., Yang, W., Lai, E. S., Ostrowski, M. A., Fuller, G. G., Dunn, A. R., Huang, N. F. 2016; 16 (1): 410-9

  Abstract

  The role of nanotopographical extracellular matrix (ECM) cues in vascular endothelial cell (EC) organization and function is not well-understood, despite the composition of nano- to microscale fibrillar ECMs within blood vessels. Instead, the predominant modulator of EC organization and function is traditionally thought to be hemodynamic shear stress, in which uniform shear stress induces parallel-alignment of ECs with anti-inflammatory function, whereas disturbed flow induces a disorganized configuration with pro-inflammatory function. Since shear stress acts on ECs by applying a mechanical force concomitant with inducing spatial patterning of the cells, we sought to decouple the effects of shear stress using parallel-aligned nanofibrillar collagen films that induce parallel EC alignment prior to stimulation with disturbed flow resulting from spatial wall shear stress gradients. Using real time live-cell imaging, we tracked the alignment, migration trajectories, proliferation, and anti-inflammatory behavior of ECs when they were cultured on parallel-aligned or randomly oriented nanofibrillar films. Intriguingly, ECs cultured on aligned nanofibrillar films remained well-aligned and migrated predominantly along the direction of aligned nanofibrils, despite exposure to shear stress orthogonal to the direction of the aligned nanofibrils. Furthermore, in stark contrast to ECs cultured on randomly oriented films, ECs on aligned nanofibrillar films exposed to disturbed flow had significantly reduced inflammation and proliferation, while maintaining intact intercellular junctions. This work reveals fundamental insights into the importance of nanoscale ECM interactions in the maintenance of endothelial function. Importantly, it provides new insight into how ECs respond to opposing cues derived from nanotopography and mechanical shear force and has strong implications in the design of polymeric conduits and bioengineered tissues.

  View details for DOI 10.1021/acs.nanolett.5b04028

  View details for PubMedID 26670737

  View details for PubMedCentralID PMC4758680

• Nanoscale Patterning of Extracellular Matrix Alters Endothelial Function under Shear Stress NANO LETTERS Nakayama, K. H., Surya, V. N., Gole, M., Walker, T. W., Yang, W., Lai, E. S., Ostrowski, M. A., Fuller, G. G., Dunn, A. R., Huang, N. F. 2016; 16 (1): 410-419

  Abstract

  The role of nanotopographical extracellular matrix (ECM) cues in vascular endothelial cell (EC) organization and function is not well-understood, despite the composition of nano- to microscale fibrillar ECMs within blood vessels. Instead, the predominant modulator of EC organization and function is traditionally thought to be hemodynamic shear stress, in which uniform shear stress induces parallel-alignment of ECs with anti-inflammatory function, whereas disturbed flow induces a disorganized configuration with pro-inflammatory function. Since shear stress acts on ECs by applying a mechanical force concomitant with inducing spatial patterning of the cells, we sought to decouple the effects of shear stress using parallel-aligned nanofibrillar collagen films that induce parallel EC alignment prior to stimulation with disturbed flow resulting from spatial wall shear stress gradients. Using real time live-cell imaging, we tracked the alignment, migration trajectories, proliferation, and anti-inflammatory behavior of ECs when they were cultured on parallel-aligned or randomly oriented nanofibrillar films. Intriguingly, ECs cultured on aligned nanofibrillar films remained well-aligned and migrated predominantly along the direction of aligned nanofibrils, despite exposure to shear stress orthogonal to the direction of the aligned nanofibrils. Furthermore, in stark contrast to ECs cultured on randomly oriented films, ECs on aligned nanofibrillar films exposed to disturbed flow had significantly reduced inflammation and proliferation, while maintaining intact intercellular junctions. This work reveals fundamental insights into the importance of nanoscale ECM interactions in the maintenance of endothelial function. Importantly, it provides new insight into how ECs respond to opposing cues derived from nanotopography and mechanical shear force and has strong implications in the design of polymeric conduits and bioengineered tissues.

  View details for DOI 10.1021/acs.nanolett.5b04028

  View details for Web of Science ID 000368322700064

  View details for PubMedCentralID PMC4758680

• Interfacial dilatational deformation accelerates particle formation in monoclonal antibody solutions SOFT MATTER Lin, G. L., Pathak, J. A., Kim, D. H., Carlson, M., Riguero, V., Kim, Y. J., Buff, J. S., Fuller, G. G. 2016; 12 (14): 3293-3302

  Abstract

  Protein molecules are amphiphilic moieties that spontaneously adsorb at the air/solution (A/S) interface to lower the surface energy. Previous studies have shown that hydrodynamic disruptions to these A/S interfaces can result in the formation of protein aggregates that are of concern to the pharmaceutical industry. Interfacial hydrodynamic stresses encountered by protein therapeutic solutions under typical manufacturing, filling, and shipping conditions will impact protein stability, prompting a need to characterize the contribution of basic fluid kinematics to monoclonal antibody (mAb) destabilization. We demonstrate that dilatational surface deformations are more important to antibody stability when compared to constant-area shear of the A/S interface. We have constructed a dilatational interfacial rheometer that utilizes simultaneous pressure and bubble shape measurements to study the mechanical stability of mAbs under interfacial aging. It has a distinct advantage over methods utilizing the Young-Laplace equation, which incorrectly describes viscoelastic interfaces. We provide visual evidence of particle ejection from dilatated A/S interfaces and spectroscopic data of ejected mAb particles. These rheological studies frame a molecular understanding of the protein-protein interactions at the complex-fluid interface.

  View details for DOI 10.1039/c5sm02830b

  View details for Web of Science ID 000373480200001

  View details for PubMedID 26891116

• Dewetting and deposition of thin films with insoluble surfactants from curved silicone hydrogel substrates. Journal of colloid and interface science Bhamla, M. S., Balemans, C., Fuller, G. G. 2015; 449: 428-435

  Abstract

  We investigate the stabilizing effect of insoluble surfactant monolayers on thin aqueous films. We first describe an experimental platform that enables the formation of aqueous films laden with dipalmitoylphosphatidylcholine (DPPC) monolayers on curved silicone hydrogel (SiHy) substrates. We show that these surfactant layers extend the lifetime of the aqueous films. The films eventually "dewet" by the nucleation and growth of dry areas and the onset of this dewetting can be controlled by the surface rheology of the DPPC layer. We thus demonstrate that increasing the interfacial rheology of the DPPC layer leads to stable films that delay dewetting. We also show that dewetting can be exploited to controllably pattern the underlying curved SiHy substrates with DPPC layers.

  View details for DOI 10.1016/j.jcis.2015.01.002

  View details for PubMedID 25628055

• Multiphase flow of miscible liquids: jets and drops EXPERIMENTS IN FLUIDS Walker, T. W., Logia, A. N., Fuller, G. G. 2015; 56 (5)

  View details for DOI 10.1007/s00348-015-1974-y

  View details for Web of Science ID 000354473900020

• Influence of Lipid Coatings on Surface Wettability Characteristics of Silicone Hydrogels LANGMUIR Bhamla, M. S., Nash, W. L., Elliott, S., Fuller, G. G. 2015; 31 (13): 3820-3828

  Abstract

  Insoluble lipids serve vital functions in our bodies and interact with biomedical devices, e.g., the tear film on a contact lens. Over a period of time, these naturally occurring lipids form interfacial coatings that modify the wettability characteristics of these foreign synthetic surfaces. In this study, we examine the deposition and consequences of tear film lipids on silicone hydrogel (SiHy) contact lenses. We use bovine meibum, which is a complex mixture of waxy esters, cholesterol esters, and lipids that is secreted from the meibomian glands located on the upper and lower eyelids of mammals. For comparison, we study two commercially available model materials: dipalmitoylphosphatidylcholine (DPPC) and cholesterol. Upon deposition, we find that DPPC and meibum remain closer to the SiHy surface than cholesterol, which diffuses further into the porous SiHy matrix. In addition, we also monitor the fate of unstable thin liquid films that consequently rupture and dewet on these lipid-decorated surfaces. This dewetting provides valuable qualitative and quantitative information about the wetting characteristics of these SiHy substrates. We observe that decorating the SiHy surface with simple model lipids such as DPPC and cholesterol increases the hydrophilicity, which consequently inhibits dewetting, whereas meibum behaves conversely.

  View details for DOI 10.1021/la503437a

  View details for Web of Science ID 000352660500007

  View details for PubMedID 25280206

• Interplay of Hydrogen Bonding and Hydrophobic Interactions to Control the Mechanical Properties of Polymer Multilayers at the Oil-Water Interface. ACS macro letters Le Tirilly, S., Tregouët, C., Bône, S., Geffroy, C., Fuller, G., Pantoustier, N., Perrin, P., Monteux, C. 2015; 4 (1): 25-29

  Abstract

  We probe the mechanical shear and compression properties of hydrogen-bonded polymer multilayers directly assembled at the oil-water interface using interfacial rheology techniques. We show that the polymer multilayers behave mechanically like a transient network, with elastic moduli that can be varied over 2 orders of magnitude by controlling the type and strength of physical interactions involved in the multilayers, which are controlled by the pH and the hydrophobicity of the polymer. Indeed, the interplay of hydrogen and hydrophobic interactions enables one to obtain a tighter and stronger network at the interface. Moreover, we show how a simple LBL process applied directly on emulsion droplets leads to encapsulation of a model oil, dodecane, as well as perfume molecules.

  View details for DOI 10.1021/mz5005772

  View details for PubMedID 35596392

• Quantification of stromal vascular cell mechanics with a linear cell monolayer rheometer JOURNAL OF RHEOLOGY Elkins, C. M., Shen, W., Khor, V. K., Kraemer, F. B., Fuller, G. G. 2015; 59 (1): 33-50

  View details for DOI 10.1122/1.4902437

  View details for Web of Science ID 000347976300003

• Integrated microfluidic platform for instantaneous flow and localized temperature control RSC ADVANCES Fang, C., Lee, D., Stober, B., Fuller, G. G., Shen, A. Q. 2015; 5 (104): 85620-85629

  View details for DOI 10.1039/c5ra19944a

  View details for Web of Science ID 000363179900058

• Lung surfactants and different contributions to thin film stability SOFT MATTER Hermans, E., Bhamla, M. S., Kao, P., Fuller, G. G., Vermant, J. 2015; 11 (41): 8048-8057

  Abstract

  The surfactant lining the walls of the alveoli in the lungs increases pulmonary compliance and prevents collapse of the lung at the end of expiration. In premature born infants, surfactant deficiency causes problems, and lung surfactant replacements are instilled to facilitate breathing. These pulmonary surfactants, which form complex structured fluid-fluid interfaces, need to spread with great efficiency and once in the alveolus they have to form a thin stable film. In the present work, we investigate the mechanisms affecting the stability of surfactant-laden thin films during spreading, using drainage flows from a hemispherical dome. Three commercial lung surfactant replacements Survanta, Curosurf and Infasurf, along with the phospholipid dipalmitoylphosphatidylcholine (DPPC), are used. The surface of the dome can be covered with human alveolar epithelial cells and experiments are conducted at the physiological temperature. Drainage is slowed down due to the presence of all the different lung surfactant replacements and therefore the thin films show enhanced stability. However, a scaling analysis combined with visualization experiments demonstrates that different mechanisms are involved. For Curosurf and Infasurf, Marangoni stresses are essential to impart stability and interfacial shear rheology does not play a role, in agreement with what is observed for simple surfactants. Survanta, which was historically the first natural surfactant used, is rheologically active. For DPPC the dilatational properties play a role. Understanding these different modes of stabilization for natural surfactants can benefit the design of effective synthetic surfactant replacements for treating infant and adult respiratory disorders.

  View details for DOI 10.1039/c5sm01603g

  View details for Web of Science ID 000363204000003

  View details for PubMedID 26307946

• Interplay of Hydrogen Bonding and Hydrophobic Interactions to Control the Mechanical Properties of Polymer Multi layers at the Oil-Water Interface ACS MACRO LETTERS Le Tirilly, S., Tregouet, C., Bone, S., Geffroy, C., Fuller, G., Pantoustier, N., Perrin, P., Monteux, C. 2015; 4 (1): 25-29

  View details for DOI 10.1021/mz5005772

  View details for Web of Science ID 000348339300008

• Molecular determinants of mechanical properties of V. cholerae biofilms at the air-liquid interface. Biophysical journal Hollenbeck, E. C., Fong, J. C., Lim, J. Y., Yildiz, F. H., Fuller, G. G., Cegelski, L. 2014; 107 (10): 2245-2252

  Abstract

  Biofilm formation increases both the survival and infectivity of Vibrio cholerae, the causative agent of cholera. V. cholerae is capable of forming biofilms on solid surfaces and at the air-liquid interface, termed pellicles. Known components of the extracellular matrix include the matrix proteins Bap1, RbmA, and RbmC, an exopolysaccharide termed Vibrio polysaccharide, and DNA. In this work, we examined a rugose strain of V. cholerae and its mutants unable to produce matrix proteins by interfacial rheology to compare the evolution of pellicle elasticity in real time to understand the molecular basis of matrix protein contributions to pellicle integrity and elasticity. Together with electron micrographs, visual inspection, and contact angle measurements of the pellicles, we defined distinct contributions of the matrix proteins to pellicle morphology, microscale architecture, and mechanical properties. Furthermore, we discovered that Bap1 is uniquely required for the maintenance of the mechanical strength of the pellicle over time and contributes to the hydrophobicity of the pellicle. Thus, Bap1 presents an important matrix component to target in the prevention and dispersal of V. cholerae biofilms.

  View details for DOI 10.1016/j.bpj.2014.10.015

  View details for PubMedID 25418293

  View details for PubMedCentralID PMC4241461

• Influence of interfacial rheology on drainage from curved surfaces. Soft matter Bhamla, M. S., Giacomin, C. E., Balemans, C., Fuller, G. G. 2014; 10 (36): 6917-6925

  Abstract

  Thin lubrication flows accompanying drainage from curved surfaces surround us (e.g., the drainage of the tear film on our eyes). These draining aqueous layers are normally covered with surface-active molecules that render the free surface viscoelastic. The non-Newtonian character of these surfaces fundamentally alters the dynamics of drainage. We show that increased film stability during drainage can occur as a consequence of enhanced surface rheology. Increasing the surfactant layer viscosity decreases the rate of drainage; however, this retarding influence is most pronounced when the insoluble surfactant layer has significant elasticity. We also present a simple theoretical model that offers qualitative support to our experimental findings.

  View details for DOI 10.1039/c3sm52934g

  View details for PubMedID 25140576

• Using in-Situ Polymerization of Conductive Polymers to Enhance the Electrical Properties of Solution-Processed Carbon Nanotube Films and Fibers ACS APPLIED MATERIALS & INTERFACES Allen, R., Pan, L., Fuller, G. G., Bao, Z. 2014; 6 (13): 9966-9974

  Abstract

  Single-walled carbon nanotubes/polymer composites typically have limited conductivity due to a low concentration of nanotubes and the insulating nature of the polymers used. Here we combined a method to align carbon nanotubes with in-situ polymerization of conductive polymer to form composite films and fibers. Use of the conducting polymer raised the conductivity of the films by 2 orders of magnitude. On the other hand, CNT fiber formation was made possible with in-situ polymerization to provide more mechanical support to the CNTs from the formed conducting polymer. The carbon nanotube/conductive polymer composite films and fibers had conductivities of 3300 and 170 S/cm, respectively. The relatively high conductivities were attributed to the polymerization process, which doped both the SWNTs and the polymer. In-situ polymerization can be a promising solution-processable method to enhance the conductivity of carbon nanotube films and fibers.

  View details for DOI 10.1021/am5019995

  View details for Web of Science ID 000338979900010

  View details for PubMedID 24914703

• Scaling analysis and mathematical theory of the interfacial stress rheometer JOURNAL OF RHEOLOGY FitzGibbon, S., Shaqfeh, E. S., Fuller, G. G., Walker, T. W. 2014; 58 (4): 999-1038

  View details for DOI 10.1122/1.4876955

  View details for Web of Science ID 000339141600008

• Microvascular Endothelial Cells Migrate Upstream and Align Against the Shear Stress Field Created by Impinging Flow BIOPHYSICAL JOURNAL Ostrowski, M. A., Huang, N. F., Walker, T. W., Verwijlen, T., Poplawski, C., Khoo, A. S., Cooke, J. P., Fuller, G. G., Dunn, A. R. 2014; 106 (2): 366-374

  Abstract

  At present, little is known about how endothelial cells respond to spatial variations in fluid shear stress such as those that occur locally during embryonic development, at heart valve leaflets, and at sites of aneurysm formation. We built an impinging flow device that exposes endothelial cells to gradients of shear stress. Using this device, we investigated the response of microvascular endothelial cells to shear-stress gradients that ranged from 0 to a peak shear stress of 9-210 dyn/cm(2). We observe that at high confluency, these cells migrate against the direction of fluid flow and concentrate in the region of maximum wall shear stress, whereas low-density microvascular endothelial cells that lack cell-cell contacts migrate in the flow direction. In addition, the cells align parallel to the flow at low wall shear stresses but orient perpendicularly to the flow direction above a critical threshold in local wall shear stress. Our observations suggest that endothelial cells are exquisitely sensitive to both magnitude and spatial gradients in wall shear stress. The impinging flow device provides a, to our knowledge, novel means to study endothelial cell migration and polarization in response to gradients in physical forces such as wall shear stress.

  View details for DOI 10.1016/j.bpj.2013.11.4502

  View details for Web of Science ID 000330132500005

  View details for PubMedID 24461011

  View details for PubMedCentralID PMC3907231

• Enhanced particle removal using viscoelastic fluids JOURNAL OF RHEOLOGY Walker, T. W., Hsu, T. T., FitzGibbon, S., Frank, C. W., Mui, D. S., Zhu, J., Mendiratta, A., Fuller, G. G. 2014; 58 (1): 63-88

  View details for DOI 10.1122/1.4832637

  View details for Web of Science ID 000329357400003

• Corneal Cell Adhesion to Contact Lens Hydrogel Materials Enhanced via Tear Film Protein Deposition. PloS one Elkins, C. M., Qi, Q. M., Fuller, G. G. 2014; 9 (8)

  Abstract

  Tear film protein deposition on contact lens hydrogels has been well characterized from the perspective of bacterial adhesion and viability. However, the effect of protein deposition on lens interactions with the corneal epithelium remains largely unexplored. The current study employs a live cell rheometer to quantify human corneal epithelial cell adhesion to soft contact lenses fouled with the tear film protein lysozyme. PureVision balafilcon A and AirOptix lotrafilcon B lenses were soaked for five days in either phosphate buffered saline (PBS), borate buffered saline (BBS), or Sensitive Eyes Plus Saline Solution (Sensitive Eyes), either pure or in the presence of lysozyme. Treated contact lenses were then contacted to a live monolayer of corneal epithelial cells for two hours, after which the contact lens was sheared laterally. The apparent cell monolayer relaxation modulus was then used to quantify the extent of cell adhesion to the contact lens surface. For both lens types, lysozyme increased corneal cell adhesion to the contact lens, with the apparent cell monolayer relaxation modulus increasing up to an order of magnitude in the presence of protein. The magnitude of this increase depended on the identity of the soaking solution: lenses soaked in borate-buffered solutions (BBS, Sensitive Eyes) exhibited a much greater increase in cell attachment upon protein addition than those soaked in PBS. Significantly, all measurements were conducted while subjecting the cells to moderate surface pressures and shear rates, similar to those experienced by corneal cells in vivo.

  View details for DOI 10.1371/journal.pone.0105512

  View details for PubMedID 25144576

  View details for PubMedCentralID PMC4140805

• Instabilities and elastic recoil of the two-fluid circular hydraulic jump EXPERIMENTS IN FLUIDS Hsu, T. T., Walker, T. W., Frank, C. W., Fuller, G. G. 2014; 55 (1)

  View details for DOI 10.1007/s00348-013-1645-9

  View details for Web of Science ID 000332151400016

• In-Situ Quantification of the Interfacial Rheological Response of Bacterial Biofilms to Environmental Stimuli PLOS ONE Ruehs, P. A., Boeni, L., Fuller, G. G., Inglis, R. F., Fischer, P. 2013; 8 (11)

  Abstract

  Understanding the numerous factors that can affect biofilm formation and stability remain poorly understood. One of the major limitations is the accurate measurement of biofilm stability and cohesiveness in real-time when exposed to changing environmental conditions. Here we present a novel method to measure biofilm strength: interfacial rheology. By culturing a range of bacterial biofilms on an air-liquid interface we were able to measure their viscoelastic growth profile during and after biofilm formation and subsequently alter growth conditions by adding surfactants or changing the nutrient composition of the growth medium. We found that different bacterial species had unique viscoelastic growth profiles, which was also highly dependent on the growth media used. We also found that we could reduce biofilm formation by the addition of surfactants or changing the pH, thereby altering the viscoelastic properties of the biofilm. Using this technique we were able to monitor changes in viscosity, elasticity and surface tension online, under constant and varying environmental conditions, thereby providing a complementary method to better understand the dynamics of both biofilm formation and dispersal.

  View details for DOI 10.1371/journal.pone.0078524

  View details for Web of Science ID 000327221600029

  View details for PubMedID 24244319

  View details for PubMedCentralID PMC3823922

• Synthesis Route for the Self-Assembly of Submicrometer-Sized Colloidosomes with Tailorable Nanopores CHEMISTRY OF MATERIALS Bollhorst, T., Grieb, T., Rosenauer, A., Fuller, G., Maas, M., Rezwan, K. 2013; 25 (17): 3464-3471

  View details for DOI 10.1021/cm401610a

  View details for Web of Science ID 000330097900008

• Aligned SWNT Films from Low-Yield Stress Gels and Their Transparent Electrode Performance ACS APPLIED MATERIALS & INTERFACES Allen, R., Fuller, G. G., Bao, Z. 2013; 5 (15): 7244-7252

  Abstract

  Carbon nanotube films are promising for transparent electrodes for solar cells and displays. Large-area alignment of the nanotubes in these films is needed to minimize the sheet resistance. We present a novel coating method to coat high-density, aligned nanotubes over large areas. Carbon nanotube gel dispersions used in this study have aligned domains and a low yield stress. A simple shearing force allows these domains to uniformly align. We use this to correlate the transparent electrode performance of single-walled carbon nanotube films with the level of partial alignment. We have found that the transparent electrode performance improves with increasing levels of alignment and in a manner slightly better than what has been previously predicted.

  View details for DOI 10.1021/am401592v

  View details for Web of Science ID 000323241100066

  View details for PubMedID 23823600

• Effect of Protein Adsorption on Dewetting and Corneal cell adhesion on Contact Lenses Bhamla, S., Elkins, C., Bergsman, D., Fuller, G. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2013

  View details for Web of Science ID 000436232701163

• The modulation of endothelial cell morphology, function, and survival using anisotropic nanofibrillar collagen scaffolds BIOMATERIALS Huang, N. F., Okogbaa, J., Lee, J. C., Jha, A., Zaitseva, T. S., Paukshto, M. V., Sun, J. S., Punjya, N., Fuller, G. G., Cooke, J. P. 2013; 34 (16): 4038-4047

  Abstract

  Endothelial cells (ECs) are aligned longitudinally under laminar flow, whereas they are polygonal and poorly aligned in regions of disturbed flow. The unaligned ECs in disturbed flow fields manifest altered function and reduced survival that promote lesion formation. We demonstrate that the alignment of the ECs may directly influence their biology, independent of fluid flow. We developed aligned nanofibrillar collagen scaffolds that mimic the structure of collagen bundles in blood vessels, and examined the effects of these materials on EC alignment, function, and in vivo survival. ECs cultured on 30-nm diameter aligned fibrils re-organized their F-actin along the nanofibril direction, and were 50% less adhesive for monocytes than the ECs grown on randomly oriented fibrils. After EC transplantation into both subcutaneous tissue and the ischemic hindlimb, EC viability was enhanced when ECs were cultured and implanted on aligned nanofibrillar scaffolds, in contrast to non-patterned scaffolds. ECs derived from human induced pluripotent stem cells and cultured on aligned scaffolds also persisted for over 28 days, as assessed by bioluminescence imaging, when implanted in ischemic tissue. By contrast, ECs implanted on scaffolds without nanopatterning generated no detectable bioluminescent signal by day 4 in either normal or ischemic tissues. We demonstrate that 30-nm aligned nanofibrillar collagen scaffolds guide cellular organization, modulate endothelial inflammatory response, and enhance cell survival after implantation in normal and ischemic tissues.

  View details for DOI 10.1016/j.biomaterials.2013.02.036

  View details for PubMedID 23480958

• Tracking the interfacial dynamics of PNiPAM soft microgels particles adsorbed at the air-water interface and in thin liquid films RHEOLOGICA ACTA Cohin, Y., Fisson, M., Jourde, K., Fuller, G. G., Sanson, N., Talini, L., Monteux, C. 2013; 52 (5): 445-454

  View details for DOI 10.1007/s00397-013-0697-3

  View details for Web of Science ID 000320314800006

• Spatial patterning of endothelium modulates cell morphology, adhesiveness and transcriptional signature BIOMATERIALS Huang, N. F., Lai, E. S., Ribeiro, A. J., Pan, S., Pruitt, B. L., Fuller, G. G., Cooke, J. P. 2013; 34 (12): 2928-2937

  Abstract

  Microscale and nanoscale structures can spatially pattern endothelial cells (ECs) into parallel-aligned organization, mimicking their cellular alignment in blood vessels exposed to laminar shear stress. However, the effects of spatial patterning on the function and global transcriptome of ECs are incompletely characterized. We used both parallel-aligned micropatterned and nanopatterned biomaterials to evaluate the effects of spatial patterning on the phenotype of ECs, based on gene expression profiling, functional characterization of monocyte adhesion, and quantification of cellular morphology. We demonstrate that both micropatterned and aligned nanofibrillar biomaterials could effectively guide EC organization along the direction of the micropatterned channels or nanofibrils, respectively. The ability of ECs to sense spatial patterning cues were abrogated in the presence of cytoskeletal disruption agents. Moreover, both micropatterned and aligned nanofibrillar substrates promoted an athero-resistant EC phenotype by reducing endothelial adhesiveness for monocytes and platelets, as well as by downregulating the expression of adhesion proteins and chemokines. We further found that micropatterned ECs have a transcriptional signature that is unique from non-patterned ECs, as well as from ECs aligned by shear stress. These findings highlight the importance of spatial patterning cues in guiding EC organization and function, which may have clinical relevance in the development of vascular grafts that promote patency.

  View details for DOI 10.1016/j.biomaterials.2013.01.017

  View details for Web of Science ID 000316038900008

  View details for PubMedID 23357369

  View details for PubMedCentralID PMC3581686

• Thermoresponsiveness of PDMAEMA. Electrostatic and Stereochemical Effects MACROMOLECULES Niskanen, J., Wu, C., Ostrowski, M., Fuller, G. G., Hietala, S., Tenhu, H. 2013; 46 (6): 2331-2340

  View details for DOI 10.1021/ma302648w

  View details for Web of Science ID 000316847500033

• 3-Hydroxybutyric Acid Interacts with Lipid Mono layers at Concentrations That Impair Consciousness LANGMUIR Hsu, T. T., Leiske, D. L., Rosenfeld, L., Sonner, J. M., Fuller, G. G. 2013; 29 (6): 1948-1955

  Abstract

  3-Hydroxybutyric acid (also referred to as β-hydroxybutyric acid or BHB), a small molecule metabolite whose concentration is elevated in type I diabetes and diabetic coma, was found to modulate the properties of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayers when added to the subphase at clinical concentrations. This is a key piece of evidence supporting the hypothesis that the anesthetic actions of BHB are due to the metabolite's abilities to alter physical properties of cell membranes, leading to indirect effects on membrane protein function. Pressure-area isotherms show that BHB changes the compressibility of the monolayer and decrease the size of the two-phase coexistence region. Epi-fluorescent microscopy further reveals that the reduction of the coexistence region is due to the significant reduction in morphology of the liquid condensed domains in the two-phase coexistence region. These changes in monolayer morphology are associated with the diminished interfacial viscosity of the monolayers (measured using an interfacial stress rheometer), which gives insight as to how changes in phase and structure may contribute to membrane function.

  View details for DOI 10.1021/la304712f

  View details for Web of Science ID 000315018200028

  View details for PubMedID 23339286

• Disruption of Escherichia coli Amyloid-Integrated Biofilm Formation at the Air-Liquid Interface by a Polysorbate Surfactant LANGMUIR Wu, C., Lim, J. Y., Fuller, G. G., Cegelski, L. 2013; 29 (3): 920-926

  Abstract

  Functional amyloid fibers termed curli contribute to bacterial adhesion and biofilm formation in Escherichia coli . We discovered that the nonionic surfactant Tween 20 inhibits biofilm formation by uropathogenic E. coli at the air-liquid interface, referred to as pellicle formation, and at the solid-liquid interface. At Tween 20 concentrations near and above the critical micelle concentration, the interfacial viscoelastic modulus is reduced to zero as cellular aggregates at the air-liquid interface are locally disconnected and eventually eliminated. Tween 20 does not inhibit the production of curli but prevents curli-integrated film formation. Our results support a model in which the hydrophobic curli fibers associated with bacteria near the air-liquid interface require access to the gas phase to formed strong physical entanglements and to form a network that can support shear stress.

  View details for DOI 10.1021/la304710k

  View details for Web of Science ID 000314082500009

  View details for PubMedID 23259693

  View details for PubMedCentralID PMC3557966

• Oriented, polymer-stabilized carbon nanotube films: influence of dispersion rheology NANOTECHNOLOGY Allen, R., Bao, Z., Fuller, G. G. 2013; 24 (1)

  Abstract

  Thin carbon nanotube films have great potential for transparent electrodes for solar cells and displays. One advantage for using carbon nanotubes is the potential for solution processing. However, research has not been done to connect solution rheological properties with the corresponding film characteristics. Here we study the rheological properties of single-walled carbon nanotube/polythiophene composite dispersions to better understand the alignment that can be achieved during deposition. Several parameters are varied to explore the cause of the alignment and the requirements of achieving a uniform, aligned carbon nanotube/polythiophene film. By understanding the dispersions thoroughly, the film quality can be predicted.

  View details for DOI 10.1088/0957-4484/24/1/015709

  View details for Web of Science ID 000312272500031

  View details for PubMedID 23221393

• Structural and rheological properties of meibomian lipid. Investigative ophthalmology & visual science Rosenfeld, L., Cerretani, C., Leiske, D. L., Toney, M. F., Radke, C. J., Fuller, G. G. 2013; 54 (4): 2720-2732

  Abstract

  We explore the unique rheological and structural properties of human and bovine meibomian lipids to provide insight into the physical behavior of the human tear-film lipid layer (TFLL).Bulk rheological properties of pooled meibomian lipids were measured by a commercial stress-controlled rheometer; a home-built interfacial stress rheometer (ISR) probed the interfacial viscoelasticity of spread layers of meibomian lipids. Small- and wide-angle x-ray scattering detected the presence and melting of dispersed crystal structures. Microscope examination under cross polarizers provided confirmation of ordered crystals. A differential scanning calorimeter (DSC) analyzed phase transitions in bulk samples of bovine meibum.Bulk and interfacial rheology measurements show that meibum is extremely viscous and highly elastic. It is also a non-Newtonian, shear-thinning fluid. Small- and wide-angle x-ray diffraction (SAXS and WAXS), as well as differential scanning calorimetry (DSC) and polarizing microscopy, confirm the presence of suspended lamellar-crystal structures at physiologic temperature.We studied meibum architecture and its relation to bulk and interfacial rheology. Bovine and human meibomian lipids exhibit similar physical properties. From all structural probes utilized, we find a melt transition near eye temperature at which lamellar crystals liquefy. Our proposed structure for the tear-film lipid layer at physiologic temperature is a highly viscoelastic, shear-thinning liquid suspension consisting of lipid lamellar-crystallite particulates immersed in a continuous liquid phase with no long-range order. When spread over on-eye tear, the TFLL is a duplex film that exhibits bulk liquid properties and two separate interfaces, air/lipid and water/lipid, with aqueous protein and surfactantlike lipids adsorbed at the water/lipid surface.

  View details for DOI 10.1167/iovs.12-10987

  View details for PubMedID 23513065

• Interfacial and Fluorescence Studies on Stereoblock Poly(N-isopropylacryl amide)s LANGMUIR Niskanen, J., Wu, C., Ostrowski, M., Fuller, G. G., Tenhu, H., Hietala, S. 2012; 28 (41): 14792-14798

  Abstract

  Aqueous solution and water-air interfacial properties of associative thermally responsive A-B-A stereoblock poly(N-isopropylacryl amide), PNIPAM, polymers were studied and compared to atactic PNIPAM. The A-B-A polymers consist of atactic PNIPAM as a hydrophilic block (either A or B) and a water-insoluble block of isotactic PNIPAM. The surface tensions of aqueous PNIPAM solutions were measured as a function of both temperature and concentration. The isotactic blocks did not have an effect on the surface activity of the solutions. Rheological measurements on the water-air interface showed that the aggregated PNIPAMs containing isotactic blocks increased the elasticity of the surface significantly as compared to the atactic reference upon heating. Two fluorescence probes, pyrene and (4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (4HP), added to the aqueous polymer solutions were concluded to reside in surroundings with lower polarity and increased microviscosity in cases when the polymers contained isotactic blocks, as compared to ordinary atactic polymers.

  View details for DOI 10.1021/la302468j

  View details for Web of Science ID 000309804900034

  View details for PubMedID 22994542

• Consequences of Interfacial Viscoelasticity on Thin Film Stability LANGMUIR Rosenfeld, L., Fuller, G. G. 2012; 28 (40): 14238-14244

  Abstract

  The phenomenon of dewetting is frequently observed in our everyday life. It is of central importance in many technological applications as well as in a variety of physical and biological systems. The presence of nonsoluble surfactants at an air/liquid interface may affect the dewetting properties of the aqueous layer. An important example is the tear film, which comprises an aqueous layer covered with a ∼100-nm-thick blanket of lipids, known as the meibomian lipids. Interfacial rheological measurements of meibomian lipids reveal that these films are remarkably viscoelastic. Tear film dewetting is of central importance to understanding tear film stability. To better understand the role of surface viscoelasticity in tear film stability, we have developed a methodology to systematically control interfacial rheology of thin aqueous layers at the onset of dewetting events. The apparatus allows control over the surface pressure of the monolayer, which is a key feature since this variable controls the surface viscoelasticity. Three insoluble monolayer materials were used: newtonian arachidyl alcohol (AA), DPPC, a phospholipid that is slightly viscoelastic, and meibum, which produces a strongly viscoelastic monolayer. It is reported that monolayers of viscoelastic surfactants are able to stabilize thin films against spontaneous dewetting. As the surface pressure of these layers is increased, their effectiveness is enhanced. Moreover, these surfactants are able to reduce the critical film thickness for dewetting. Meibum is particularly effective in stabilizing thin films. Our results suggest that the meibomian lipids play a vital role in maintaining tear film stability in addition to suppressing evaporation.

  View details for DOI 10.1021/la302731z

  View details for Web of Science ID 000309505000014

  View details for PubMedID 22989061

• Aligned nanofibrillar collagen regulates endothelial organization and migration REGENERATIVE MEDICINE Lai, E. S., Huang, N. F., Cooke, J. P., Fuller, G. G. 2012; 7 (5): 649-661

  Abstract

  Modulating endothelial cell (EC) morphology and motility, with the aim to influence their biology, might be beneficial for the treatment of vascular disease. We examined the effect of nanoscale matrix anisotropy on EC organization and migration for vascular tissue engineering applications.We developed a flow processing technique to generate anisotropic nanofibrillar collagen. Human ECs were cultured on aligned or on randomly oriented collagen, and their cellular alignment and cytoskeletal organization were characterized by immunofluorescence staining and time-lapse microscopy.ECs were elongated along the direction of aligned collagen nanofibrils and had organized focal adhesions. Cellular protrusion migrated with greater directionality and higher velocity along the anisotropic nanofibrils compared with cells on random nanofibrils. The flow technique can be adapted to fabricate vascular grafts that support the endothelial phenotype.Aligned nanofibrillar collagen regulates EC organization and migration, which can significantly contribute to the development of vascular grafts.

  View details for DOI 10.2217/RME.12.48

  View details for Web of Science ID 000308387900011

  View details for PubMedID 22954436

  View details for PubMedCentralID PMC3589994

• Extensional rheometry at interfaces: Analysis of the Cambridge Interfacial Tensiometer JOURNAL OF RHEOLOGY Verwijlen, T., Leiske, D. L., Moldenaers, P., Vermant, J., Fuller, G. G. 2012; 56 (5): 1225-1247

  View details for DOI 10.1122/1.4733717

  View details for Web of Science ID 000306761300011

• Role of shear-thinning on the dynamics of rinsing flow by an impinging jet PHYSICS OF FLUIDS Walker, T. W., Hsu, T. T., Frank, C. W., Fuller, G. G. 2012; 24 (9)

  View details for DOI 10.1063/1.4752765

  View details for Web of Science ID 000309425800022

• Molecular Structure of Interfacial Human Meibum Films LANGMUIR Leiske, D. L., Miller, C. E., Rosenfeld, L., Cerretani, C., Ayzner, A., Lin, B., Meron, M., Senchyna, M., Ketelson, H. A., Meadows, D., Srinivasan, S., Jones, L., Radke, C. J., Toney, M. F., Fuller, G. G. 2012; 28 (32): 11867-11874

  Abstract

  Meibum is the primary component of the tear film lipid layer. Thought to play a role in tear film stabilization, understanding the physical properties of meibum and how they change with disease will be valuable in identifying dry eye treatment targets. Grazing incidence X-ray diffraction and X-ray reflectivity were applied to meibum films at an air-water interface to identify molecular organization. At room temperature, interfacial meibum films formed two coexisting scattering phases with rectangular lattices and next-nearest neighbor tilts, similar to the Ov phase previously identified in fatty acids. The intensity of the diffraction peaks increased with compression, although the lattice spacing and molecular tilt angle remained constant. Reflectivity measurements at surface pressures of 18 mN/m and above revealed multilayers with d-spacings of 50 Å, suggesting that vertical organization rather than lateral was predominantly affected by meibum-film compression.

  View details for DOI 10.1021/la301321r

  View details for Web of Science ID 000307479000023

• Molecular structure of interfacial human meibum films. Langmuir Leiske, D. L., Miller, C. E., Rosenfeld, L., Cerretani, C., Ayzner, A., Lin, B., Meron, M., Senchyna, M., Ketelson, H. A., Meadows, D., Srinivasan, S., Jones, L., Radke, C. J., Toney, M. F., Fuller, G. G. 2012; 28 (32): 11858-11865

  Abstract

  Meibum is the primary component of the tear film lipid layer. Thought to play a role in tear film stabilization, understanding the physical properties of meibum and how they change with disease will be valuable in identifying dry eye treatment targets. Grazing incidence X-ray diffraction and X-ray reflectivity were applied to meibum films at an air-water interface to identify molecular organization. At room temperature, interfacial meibum films formed two coexisting scattering phases with rectangular lattices and next-nearest neighbor tilts, similar to the Ov phase previously identified in fatty acids. The intensity of the diffraction peaks increased with compression, although the lattice spacing and molecular tilt angle remained constant. Reflectivity measurements at surface pressures of 18 mN/m and above revealed multilayers with d-spacings of 50 Å, suggesting that vertical organization rather than lateral was predominantly affected by meibum-film compression.

  View details for DOI 10.1021/la301321r

  View details for PubMedID 22783994

• Quantitative Analysis of Amyloid-Integrated Biofilms Formed by Uropathogenic Escherichia coli at the Air-Liquid Interface BIOPHYSICAL JOURNAL Wu, C., Lim, J. Y., Fuller, G. G., Cegelski, L. 2012; 103 (3): 464-471

  Abstract

  Bacterial biofilms are complex multicellular assemblies, characterized by a heterogeneous extracellular polymeric matrix, that have emerged as hallmarks of persistent infectious diseases. New approaches and quantitative data are needed to elucidate the composition and architecture of biofilms, and such data need to be correlated with mechanical and physicochemical properties that relate to function. We performed a panel of interfacial rheological measurements during biofilm formation at the air-liquid interface by the Escherichia coli strain UTI89, which is noted for its importance in studies of urinary tract infection and for its assembly of functional amyloid fibers termed curli. Brewster-angle microscopy and measurements of the surface elasticity (G(s)') and stress-strain response provided sensitive and quantitative parameters that revealed distinct stages during bacterial colonization, aggregation, and eventual formation of a pellicle at the air-liquid interface. Pellicles that formed under conditions that upregulate curli production exhibited an increase in strength and viscoelastic properties as well as a greater ability to recover from stress-strain perturbation. The results suggest that curli, as hydrophobic extracellular amyloid fibers, enhance the strength, viscoelasticity, and resistance to strain of E. coli biofilms formed at the air-liquid interface.

  View details for DOI 10.1016/j.bpj.2012.06.049

  View details for Web of Science ID 000307427700011

  View details for PubMedID 22947862

  View details for PubMedCentralID PMC3414876

• Isocitrate dehydrogenase 1 R132H mutation is not detected in angiocentric glioma ANNALS OF DIAGNOSTIC PATHOLOGY Raghunathan, A., Olar, A., Vogel, H., Parker, J. R., Coventry, S. C., Debski, R., Albarracin, C. T., Aldape, K. D., Cahill, D. P., Powell, S. Z., Fuller, G. N. 2012; 16 (4): 255-259

  Abstract

  Mutations of isocitrate dehydrogenase-1 gene (IDH1), most commonly resulting in replacement of arginine at position 132 by histidine (R132H), have been described in World Health Organization grade II and III diffuse gliomas and secondary glioblastoma. Immunohistochemistry using a mouse monoclonal antibody has a high specificity and sensitivity for detecting IDH1 R132H mutant protein in sections from formalin-fixed, paraffin-embedded tissue. Angiocentric glioma (AG), a unique neoplasm with mixed phenotypic features of diffuse glioma and ependymoma, has recently been codified as a grade I neoplasm in the 2007 World Health Organization classification of central nervous system tumors. The present study was designed to evaluate IDH1 R132H protein in AG. Three cases of AG were collected, and the diagnoses were confirmed. Expression of mutant IDH1 R132H protein was determined by immunohistochemistry on representative formalin-fixed, paraffin-embedded sections using the antihuman mouse monoclonal antibody IDH1 R132H (Dianova, Hamburg, Germany). Known IDH1 mutation-positive and IDH1 wild-type cases of grade II to IV glioma served as positive and negative controls. All 3 patients were male, aged 3, 5, and 15 years, with intra-axial tumors in the right posterior parietal-occipital lobe, right frontal lobe, and left frontal lobe, respectively. All 3 cases showed characteristic morphologic features of AG, including a monomorphous population of slender bipolar cells that diffusely infiltrated cortical parenchyma and ensheathed cortical blood vessels radially and longitudinally. All 3 cases were negative for the presence of IDH1 R132H mutant protein (0/3). All control cases showed appropriate reactivity. IDH1 R132H mutation has been described as a common molecular signature of grade II and III diffuse gliomas and secondary glioblastoma; however, AG, which exhibits some features of diffuse glioma, has not been evaluated. The absence of mutant IDH1 R132H protein expression in AG may help further distinguish this unique neoplasm from diffuse glioma.

  View details for DOI 10.1016/j.anndiagpath.2011.11.003

  View details for Web of Science ID 000306628200004

  View details for PubMedID 22445362

• Oriented collagen as a potential cochlear implant electrode surface coating to achieve directed neurite outgrowth EUROPEAN ARCHIVES OF OTO-RHINO-LARYNGOLOGY Volkenstein, S., Kirkwood, J. E., Lai, E., Dazert, S., Fuller, G. G., Heller, S. 2012; 269 (4): 1111-1116

  Abstract

  In patients with severe to profound hearing loss, cochlear implants (CIs) are currently the only therapeutic option when the amplification with conventional hearing aids does no longer lead to a useful hearing experience. Despite its great success, there are patients in which benefit from these devices is rather limited. One reason may be a poor neuron-device interaction, where the electric fields generated by the electrode array excite a wide range of tonotopically organized spiral ganglion neurons at the cost of spatial resolution. Coating of CI electrodes to provide a welcoming environment combined with suitable surface chemistry (e.g. with neurotrophic factors) has been suggested to create a closer bioelectrical interface between the electrode array and the target tissue, which might lead to better spatial resolution, better frequency discrimination, and ultimately may improve speech perception in patients. Here we investigate the use of a collagen surface with a cholesteric banding structure, whose orientation can be systemically controlled as a guiding structure for neurite outgrowth. We demonstrate that spiral ganglion neurons survive on collagen-coated surfaces and display a directed neurite growth influenced by the direction of collagen fibril deposition. The majority of neurites grow parallel to the orientation direction of the collagen. We suggest collagen coating as a possible future option in CI technology to direct neurite outgrowth and improve hearing results for affected patients.

  View details for DOI 10.1007/s00405-011-1775-8

  View details for Web of Science ID 000301978000007

  View details for PubMedID 21952794

• Assembly of submicron colloidosomes with silica nanoparticles featuring a selective permeability Maas, M., Fuller, G. G. AMER CHEMICAL SOC. 2012

  View details for Web of Science ID 000324475103578

• Temperature-Induced Transitions in the Structure and Interfacial Rheology of Human Meibum BIOPHYSICAL JOURNAL Leiske, D. L., Leiske, C. I., Leiske, D. R., Toney, M. F., Senchyna, M., Ketelson, H. A., Meadows, D. L., Fuller, G. G. 2012; 102 (2): 369-376

  Abstract

  Meibomian lipids are the primary component of the lipid layer of the tear film. Composed primarily of a mixture of lipids, meibum exhibits a range of melt temperatures. Compositional changes that occur with disease may alter the temperature at which meibum melts. Here we explore how the mechanical properties and structure of meibum from healthy subjects depend on temperature. Interfacial films of meibum were highly viscoelastic at 17°C, but as the films were heated to 30°C the surface moduli decreased by more than two orders of magnitude. Brewster angle microscopy revealed the presence of micron-scale inhomogeneities in meibum films at higher temperatures. Crystalline structure was probed by small angle x-ray scattering of bulk meibum, which showed evidence of a majority crystalline structure in all samples with lamellar spacing of 49 Å that melted at 34°C. A minority structure was observed in some samples with d-spacing at 110 Å that persisted up to 40°C. The melting of crystalline phases accompanied by a reduction in interfacial viscosity and elasticity has implications in meibum behavior in the tear film. If the melt temperature of meibum was altered significantly from disease-induced compositional changes, the resultant change in viscosity could alter secretion of lipids from meibomian glands, or tear-film stabilization properties of the lipid layer.

  View details for DOI 10.1016/j.bpj.2011.12.017

  View details for Web of Science ID 000299244100023

  View details for PubMedID 22339874

  View details for PubMedCentralID PMC3260664

• Interfacial Rheology of Natural Silk Fibroin at Air/Water and Oil/Water Interfaces LANGMUIR Wang, L., Xie, H., Qiao, X., Goffin, A., Hodgkinson, T., Yuan, X., Sun, K., Fuller, G. G. 2012; 28 (1): 459-467

  Abstract

  The interfacial viscoelastic behavior of natural silk fibroin at both the air/water and oil/water interfaces is reported. This natural multiblock copolymer is found to be strongly amphiphilic and forms stable films at these interfaces. The result is an interfacial layer that is rheologically complex with strong surface elastic moduli that are only slightly frequency-dependent. The kinetics of surface viscoelastic evolution are reported as functions of time for various concentrations of the spread films. Films deposited by Langmuir-Blodgett deposition were studied by scanning electron microscopy (SEM) to reveal a fibrous structure at the interface. The production of stable O/W emulsions by silk fibroin further confirms the generation of the elastic films at the oil/water interfaces.

  View details for DOI 10.1021/la2041373

  View details for Web of Science ID 000298904900061

  View details for PubMedID 22107484

• Complex Fluid-Fluid Interfaces: Rheology and Structure ANNUAL REVIEW OF CHEMICAL AND BIOMOLECULAR ENGINEERING, VOL 3 Fuller, G. G., Vermant, J. 2012; 3: 519-543

  Abstract

  Complex fluid-fluid interfaces are common to living systems, foods, personal products, and the environment. They occur wherever surface-active molecules and particles collect at fluid interfaces and render them nonlinear in their response to flow and deformation. When this occurs, the interfaces acquire a complex microstructure that must be interrogated. Interfacial rheological material properties must be measured to appreciate their role in such varied processes as lung function, cell division, and foam and emulsion stability. This review presents the methods that have been devised to determine the microstructure of complex fluid-fluid interfaces. Complex interfacial microstructure leads to rheological complexity. This behavior is often responsible for stabilizing interfacial systems such as foams and emulsions, and it can also have a profound influence on wetting/dewetting dynamics. Interfacial rheological characterization relies on the development of tools with the sensitivity to respond to small surface stresses in a way that isolates them from bulk stresses. This development is relatively recent, and reviews of methods for both shear and dilatational measurements are offered here.

  View details for DOI 10.1146/annurev-chembioeng-061010-114202

  View details for Web of Science ID 000307955800023

  View details for PubMedID 22541047

• Insertion Mechanism of a Poly(ethylene oxide)-poly(butylene oxide) Block Copolymer into a DPPC Monolayer LANGMUIR Leiske, D. L., Meckes, B., Miller, C. E., Wu, C., Walker, T. W., Lin, B., Meron, M., Ketelson, H. A., Toney, M. F., Fuller, G. G. 2011; 27 (18): 11444-11450

  Abstract

  Interactions between amphiphilic block copolymers and lipids are of medical interest for applications such as drug delivery and the restoration of damaged cell membranes. A series of monodisperse poly(ethylene oxide)-poly(butylene oxide) (EOBO) block copolymers were obtained with two ratios of hydrophilic/hydrophobic block lengths. We have explored the surface activity of EOBO at a clean interface and under 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayers as a simple cell membrane model. At the same subphase concentration, EOBO achieved higher equilibrium surface pressures under DPPC compared to a bare interface, and the surface activity was improved with longer poly(butylene oxide) blocks. Further investigation of the DPPC/EOBO monolayers showed that combined films exhibited similar surface rheology compared to pure DPPC at the same surface pressures. DPPC/EOBO phase separation was observed in fluorescently doped monolayers, and within the liquid-expanded liquid-condensed coexistence region for DPPC, EOBO did not drastically alter the liquid-condensed domain shapes. Grazing incidence X-ray diffraction (GIXD) and X-ray reflectivity (XRR) quantitatively confirmed that the lattice spacings and tilt of DPPC in lipid-rich regions of the monolayer were nearly equivalent to those of a pure DPPC monolayer at the same surface pressures.

  View details for DOI 10.1021/la2016879

  View details for Web of Science ID 000294790500022

  View details for PubMedID 21834565

• Vascular anastomosis using controlled phase transitions in poloxamer gels NATURE MEDICINE Chang, E. I., Galvez, M. G., Glotzbach, J. P., Hamou, C. D., El-Ftesi, S., Rappleye, C. T., Sommer, K., Rajadas, J., Abilez, O. J., Fuller, G. G., Longaker, M. T., Gurtner, G. C. 2011; 17 (9): 1147-U160

  Abstract

  Vascular anastomosis is the cornerstone of vascular, cardiovascular and transplant surgery. Most anastomoses are performed with sutures, which are technically challenging and can lead to failure from intimal hyperplasia and foreign body reaction. Numerous alternatives to sutures have been proposed, but none has proven superior, particularly in small or atherosclerotic vessels. We have developed a new method of sutureless and atraumatic vascular anastomosis that uses US Food and Drug Administration (FDA)-approved thermoreversible tri-block polymers to temporarily maintain an open lumen for precise approximation with commercially available glues. We performed end-to-end anastomoses five times more rapidly than we performed hand-sewn controls, and vessels that were too small (<1.0 mm) to sew were successfully reconstructed with this sutureless approach. Imaging of reconstructed rat aorta confirmed equivalent patency, flow and burst strength, and histological analysis demonstrated decreased inflammation and fibrosis at up to 2 years after the procedure. This new technology has potential for improving efficiency and outcomes in the surgical treatment of cardiovascular disease.

  View details for DOI 10.1038/nm.2424

  View details for Web of Science ID 000294605100038

  View details for PubMedID 21873986

• Designing a tubular matrix of oriented collagen fibrils for tissue engineering ACTA BIOMATERIALIA Lai, E. S., Anderson, C. M., Fuller, G. G. 2011; 7 (6): 2448-2456

  Abstract

  A scaffold composed entirely of an extracellular matrix component, such as collagen, with cellular level control would be highly desirable for applications in tissue engineering. In this article we introduce a novel, straightforward flow processing technique that fabricates a small diameter tubular matrix constructed of anisotropic collagen fibrils. Scanning electron microscopy confirmed the uniform alignment of the collagen fibrils and subsequent matrix-induced alignment of human fibroblasts. The uniform alignment of the fibroblasts along the collagen fibrils demonstrated the ability of the aligned fibrils to successfully dictate the directional growth of human fibroblasts through contact guidance. Various non-cytotoxic cross-linking techniques were also applied to the collagen conduit to enhance the mechanical properties. Tensile testing and burst pressure were the two measurements performed to characterize the mechanical integrity of the conduit. Mechanical characterization of the cross-linked collagen conduits identified 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride cross-linking as the most promising technique to reinforce the mechanical properties of native collagen. An oriented conduit of biocompatible material has been fabricated with decent mechanical strength and at a small diameter scale, which is especially applicable in engineering cardiovascular tissues and nerve grafts.

  View details for DOI 10.1016/j.actbio.2011.03.012

  View details for Web of Science ID 000291181800010

  View details for PubMedID 21414424

• Role of fluid elasticity on the dynamics of rinsing flow by an impinging jet PHYSICS OF FLUIDS Hsu, T. T., Walker, T. W., Frank, C. W., Fuller, G. G. 2011; 23 (3)

  View details for DOI 10.1063/1.3567215

  View details for Web of Science ID 000289153000015

• Preparation of Mineralized Nanofibers: Collagen Fibrils Containing Calcium Phosphate NANO LETTERS Maas, M., Guo, P., Keeney, M., Yang, F., Hsu, T. M., Fuller, G. G., Martin, C. R., Zare, R. N. 2011; 11 (3): 1383-1388

  Abstract

  We report a straightforward, bottom-up, scalable process for preparing mineralized nanofibers. Our procedure is based on flowing feed solution, containing both inorganic cations and polymeric molecules, through a nanoporous membrane into a receiver solution with anions, which leads to the formation of mineralized nanofibers at the exit of the pores. With this strategy, we were able to achieve size control of the nanofiber diameters. We illustrate this approach by producing collagen fibrils with calcium phosphate incorporated inside the fibrils. This structure, which resembles the basic constituent of bones, assembles itself without the addition of noncollagenous proteins or their polymeric substitutes. Rheological experiments demonstrated that the stiffness of gels derived from these fibrils is enhanced by mineralization. Growth experiments of human adipose derived stem cells on these gels showed the compatibility of the fibrils in a tissue-regeneration context.

  View details for DOI 10.1021/nl200116d

  View details for Web of Science ID 000288061500082

  View details for PubMedID 21280646

  View details for PubMedCentralID PMC3053435

• Interfacial shear rheology of highly confined glassy polymers SOFT MATTER Srivastava, S., Leiske, D., Basu, J. K., Fuller, G. G. 2011; 7 (5): 1994-2000

  View details for DOI 10.1039/c0sm00839g

  View details for Web of Science ID 000287588800057

• Editorial: dynamics and rheology of complex fluid-fluid interfaces SOFT MATTER Fuller, G. G., Vermant, J. 2011; 7 (17): 7583-7585

  View details for DOI 10.1039/c1sm90055b

  View details for Web of Science ID 000294014200001

• Influence of surface rheology on dynamic wetting of droplets coated with insoluble surfactants SOFT MATTER Leiske, D. L., Monteux, C., Senchyna, M., Ketelson, H. A., Fuller, G. G. 2011; 7 (17): 7747-7753

  View details for DOI 10.1039/c1sm05231d

  View details for Web of Science ID 000294014200019

• Thin Film Formation of Silica Nanoparticle/Lipid Composite Films at the Fluid-Fluid Interface LANGMUIR Maas, M., Ooi, C. C., Fuller, G. G. 2010; 26 (23): 17867-17873

  Abstract

  We report a new and simple method for the formation of thin films at the interface between aqueous silica Ludox dispersions and lipid solutions in decane. The lipids used are stearic acid, stearyl amine, and stearyl alcohol alongside silica Ludox nanoparticle dispersions of varying pH. At basic pH thin films consisting of a mixture of stearic acid and silica nanoparticles precipitate at the interface. At acidic and neutral pH we were able to produce thin films consisting of stearyl amine and silica particles. The film growth was studied in situ with interfacial shear rheology. In addition to that, surface pressure isotherm and dynamic light scattering experiments were performed. The films all exhibit strong dynamic rheological moduli, rendering them an interesting material for applications such as capsule formation, surface coating, or as functional membranes.

  View details for DOI 10.1021/la103492a

  View details for Web of Science ID 000284732300018

  View details for PubMedID 21067193

• The interfacial viscoelastic properties and structures of human and animal Meibomian lipids EXPERIMENTAL EYE RESEARCH Leiske, D. L., Raju, S. R., Ketelson, H. A., Millar, T. J., Fuller, G. G. 2010; 90 (5): 598-604

  Abstract

  As the interface between the aqueous layer of the tear film and air, the lipid layer plays a large role in maintaining tear film stability. Meibomian lipids are the primary component of the lipid layer; therefore the physical properties of these materials may be particularly crucial to the functionality of the tear film. Surface pressure versus area isotherms, interfacial shear and extensional rheology, and Brewster angle microscopy (BAM) were used to characterize the Meibomian lipids from different species known to have different lipid compositions. The isotherms of humans, bovinae, wallabies, rabbits and kultarrs (a small desert marsupial) were qualitatively similar with little hysteresis between compression and expansion cycles. In contrast, several isocycles were necessary to achieve equilibrium behavior in the koala lipids. With the exception of kultarr lipids, the interfacial complex viscosity of all samples increased by one or two orders of magnitude between surface pressures of 5 mN/m and 20 mN/m and exhibited classic gel behavior at higher surface pressures. In contrast, the kultarr lipids were very fluid up to 22 mN/m; the behavior did not depend on surface pressure. Human lipids were very deformable in extensional flow and the BAM images revealed that the film became more homogeneous with compression as the elasticity of the film increased. The morphology of the kultarr lipids did not change with compression indicating a strong correlation between film structure and behavior. These results suggest that the lipid layer of the tear film forms a gel in vivo, which may aid in mechanically stabilization of the tear film.

  View details for DOI 10.1016/j.exer.2010.02.004

  View details for Web of Science ID 000276988200009

  View details for PubMedID 20156438

• Interfacial Flow Processing of Collagen LANGMUIR Goffin, A. J., Rajadas, J., Fuller, G. G. 2010; 26 (5): 3514-3521

  Abstract

  A new method for creating substrates made out of ordered collagen fibers, on which cells in culture can align, is proposed. The substrates can be used for research in cell culture, and this research presents a significant advance in the technology to coat implants in order to improve cell adhesion. In the procedure presented here, a molecular solution of collagen is spread at the interface of a saline solution and air to induce fiber formation, compressed at a high speed to induce orientation and deposited on solid substrates via Langmuir-Blodgett transfer. Several interfacial techniques are employed to investigate the behavior of collagen, which is shown to be dependent on the salt concentration of the subphase as well as the temperature. After Langmuir-Blodgett transfer, primary human fibroblasts and adipose-derived stem cells are cultured on the collagen substrates. Both types of cells respond favorably to the collagen orientation and align with the deposited fibers. The technique presented here provides a simple method to produce well-controlled, oriented collagen substrates that can be used in tissue culture research or scaffolding applications without the use of additives and/or bioincompatible materials.

  View details for DOI 10.1021/la9031317

  View details for Web of Science ID 000274636900079

  View details for PubMedID 20000428

• Charge Interaction between Particle-Laden Fluid Interfaces LANGMUIR Xu, H., Kirkwood, J., Lask, M., Fuller, G. 2010; 26 (5): 3160-3164

  Abstract

  Experiments are described where two oil/water interfaces laden with charged particles move at close proximity relative to one another. The particles on one of the interfaces were observed to be attracted toward the point of closest approach, forming a denser particle monolayer, while the particles on the opposite interface were repelled away from this point, forming a particle depletion zone. Such particle attraction/repulsion was observed even if one of the interfaces was free of particles. This phenomenon can be explained by the electrostatic interaction between the two interfaces, which causes surface charges (charged particles and ions) to redistribute in order to satisfy surface electric equipotential at each interface. In a forced particle oscillation experiment, we demonstrated the control of charged particle positions on the interface by manipulating charge interaction between interfaces.

  View details for DOI 10.1021/la903099a

  View details for Web of Science ID 000274636900028

  View details for PubMedID 19852479

• A double wall-ring geometry for interfacial shear rheometry RHEOLOGICA ACTA Vandebril, S., Franck, A., Fuller, G. G., Moldenaers, P., Vermant, J. 2010; 49 (2): 131-144

  View details for DOI 10.1007/s00397-009-0407-3

  View details for Web of Science ID 000273854300002

• Surface Rheology of a Polymer Monolayer: Effects of Polymer Chain Length and Compression Rate LANGMUIR Spigone, E., Cho, G., Fuller, G. G., Cicuta, P. 2009; 25 (13): 7457-7464

  Abstract

  We study surface layers of a simple homopolymer poly(vinyl acetate) on the air-water interface as a function of the concentration and the polymer molecular weight. Our results suggest that there is an effect of the compression rate on both the structure of the layers and their rheological behavior, while the length of the chain influences only the rheology. At very low compression speeds, the surface layer of short chains does not exhibit the classical semi-dilute regime behavior, forming instead a solid phase. For fluid layers, we report on the dependence of surface viscosity upon the concentration, showing a first crossover, which happens close to the semi-dilute-concentrated regime boundary, from a scaling behavior with the concentration to an Eyring-like liquid. A second rheological transition happens at very high concentrations, near close packing, where the Newtonian liquid phase gives way to a soft solid phase.

  View details for DOI 10.1021/la900385y

  View details for Web of Science ID 000267533800047

  View details for PubMedID 19374337

• Isovaleric, Methylmalonic, and Propionic Acid Decrease Anesthetic EC50 in Tadpoles, Modulate Glycine Receptor Function, and Interact with the Lipid 1,2-Dipalmitoyl-Sn-Glycero-3-Phosphocholine 18th Annual Neuropharmacology Conference 2008 Weng, Y., Hsu, T. T., Zhao, J., Nishimura, S., Fuller, G. G., Sonner, J. M. LIPPINCOTT WILLIAMS & WILKINS. 2009: 1538–45

  Abstract

  Elevated concentrations of isovaleric (IVA), methylmalonic (MMA), and propionic acid are associated with impaired consciousness in genetic diseases (organic acidemias). We conjectured that part of the central nervous system depression observed in these disorders was due to anesthetic effects of these metabolites. We tested three hypotheses. First, that these metabolites would have anesthetic-sparing effects, possibly being anesthetics by themselves. Second, that these compounds would modulate glycine and gamma-aminobutyric acid (GABA(A)) receptor function, increasing chloride currents through these channels as potent clinical inhaled anesthetics do. Third, that these compounds would affect physical properties of lipids.Anesthetic EC(50)s were measured in Xenopus laevis tadpoles. Glycine and GABA(A) receptors were expressed in Xenopus laevis oocytes and studied using two-electrode voltage clamping. Pressure-area isotherms of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayers were measured with and without added organic acids.IVA acid was an anesthetic in tadpoles, whereas MMA and propionic acid decreased isoflurane's EC(50) by half. All three organic acids concentration-dependently increased current through alpha(1) glycine receptors. There were minimal effects on alpha(1)beta(2)gamma(2s) GABA(A) receptors. The organic acids increased total lateral pressure (surface pressure) of DPPC monolayers, including at mean molecular areas typical of bilayers.IVA, MMA, and propionic acid have anesthetic effects in tadpoles, positively modulate glycine receptor function and affect physical properties of DPPC monolayers.

  View details for DOI 10.1213/ane.0b013e31819cd964

  View details for Web of Science ID 000265422300029

  View details for PubMedID 19372333

  View details for PubMedCentralID PMC2897242

• Liquid Crystalline Collagen: A Self-Assembled Morphology for the Orientation of Mammalian Cells LANGMUIR Kirkwood, J. E., Fuller, G. G. 2009; 25 (5): 3200-3206

  Abstract

  We report the creation of collagen films having a cholesteric banding structure with an orientation that can be systematically controlled. The action of hydrodynamic flow and rapid desiccation was used to influence the orientation of collagen fibrils, producing a film with a twisted plywood architecture. Adult human fibroblasts cultured on these substrates orient in the direction of the flow deposition, and filopodia are extended onto individual bands. Atomic force microscopy reveals the assembly of 30 nm collagen fibrils into the uniform cholesteric collagen films with a periodic surface relief. The generation of collagen with a reticular, "basket-weave" morphology when using lower concentrations is also discussed.

  View details for DOI 10.1021/la803736x

  View details for Web of Science ID 000263770800099

  View details for PubMedID 19437784

• Langmuir Monolayers of Straight-Chain and Branched Hexadecanol and Eicosanol Mixtures LANGMUIR Kurtz, R. E., Toney, M. F., Pople, J. A., Lin, B., Meron, M., Majewski, J., Lange, A., Fuller, G. G. 2008; 24 (24): 14005-14014

  Abstract

  Langmuir monolayers of straight-chain and branched hexadecanol and eicosanol mixtures were previously studied using surface pressure- area isotherms, Brewster angle microscopy, and interfacial rheology. In this paper, we investigate the structure of these fatty alcohol mixtures using these previous results together with X-ray diffraction and reflectivity measurements, which provide a better understanding of the structure of the monolayer in terms of the phase segregation and location of branched chains. For eicosanol below 25 mN/m, the branched chains are incorporated into the monolayer, yet they are phase-separated from the straight chains. At higher surface pressures, the branched chains are expelled from the monolayer and presumably form micelles or some other aggregate in the subphase. In contrast, the hexadecanol branched chains are not present in the monolayer at any surface pressure. These behaviors are interpreted with the help of the X-ray measurements and density profiles, and are explained in terms of straight-chain flexibility. We will discuss the effect of the monolayer structure on the surface shear viscosity. These studies provide a deeper understanding of the structure and behavior of amphiphilic mixtures, and will ultimately aid in developing models for lipids, micelle formation, and other important biological functions.

  View details for DOI 10.1021/la802467e

  View details for Web of Science ID 000261631700029

  View details for PubMedID 19360939

• Small Molecule, Non-Peptide p75(NTR) Ligands Inhibit A beta-Induced Neurodegeneration and Synaptic Impairment PLOS ONE Yang, T., Knowles, J. K., Lu, Q., Zhang, H., Arancio, O., Moore, L. A., Chang, T., Wang, Q., Andreasson, K., Rajadas, J., Fuller, G. G., Xie, Y., Massa, S. M., Longo, F. M. 2008; 3 (11)

  Abstract

  The p75 neurotrophin receptor (p75(NTR)) is expressed by neurons particularly vulnerable in Alzheimer's disease (AD). We tested the hypothesis that non-peptide, small molecule p75(NTR) ligands found to promote survival signaling might prevent Abeta-induced degeneration and synaptic dysfunction. These ligands inhibited Abeta-induced neuritic dystrophy, death of cultured neurons and Abeta-induced death of pyramidal neurons in hippocampal slice cultures. Moreover, ligands inhibited Abeta-induced activation of molecules involved in AD pathology including calpain/cdk5, GSK3beta and c-Jun, and tau phosphorylation, and prevented Abeta-induced inactivation of AKT and CREB. Finally, a p75(NTR) ligand blocked Abeta-induced hippocampal LTP impairment. These studies support an extensive intersection between p75(NTR) signaling and Abeta pathogenic mechanisms, and introduce a class of specific small molecule ligands with the unique ability to block multiple fundamental AD-related signaling pathways, reverse synaptic impairment and inhibit Abeta-induced neuronal dystrophy and death.

  View details for DOI 10.1371/journal.pone.0003604

  View details for Web of Science ID 000265134200003

  View details for PubMedID 18978948

  View details for PubMedCentralID PMC2575383

• Effect of Lysozyme Adsorption on the Interfacial Rheology of DPPC and Cholesteryl Myristate Films LANGMUIR Nishimura, S. Y., Magana, G. M., Ketelson, H. A., Fuller, G. G. 2008; 24 (20): 11728-11733

  Abstract

  A model tear film lipid layer composed of a binary mixture of cholesteryl myristate (CM) and 1,2-dipalmitoyl- sn-glycero-3-phosphocholine (DPPC) was characterized using surface tension measurements, Brewster angle microscopy (BAM) and interfacial stress rheology (ISR). Isotherms showed that films containing >or=90 mol % CM have a 17-fold greater % area loss between the first and second compressions than the films with less CM. BAM images clearly showed that CM films did not expand after compression, and solid-like regions extending 1-2 mm were observed at low pressures (1 mN/m). Lipid films with or=50 mol % CM became elastic at higher surface pressures. Increasing CM content reduced the surface pressure at which the mixed film became elastic. Lysozyme adsorption into a CM film increased the compressibility and resulted in a more expanded film. Lysozyme increased the ductility of the CM/DPPC films with no film breakdown occurring up to the highest pressure measured (40 mN/m). In summary, CM increased the elasticity of the lipid films, but also caused them to become brittle and incapable of expansion following compression. Lysozyme adsorption increased the ductility and decreased the isotherm hysteresis for CM/DPPC films.

  View details for DOI 10.1021/la8016485

  View details for Web of Science ID 000260049300056

  View details for PubMedID 18783258

• Interaction of human whole saliva and astringent dietary compounds investigated by interfacial shear rheology FOOD HYDROCOLLOIDS Rossetti, D., Yakubov, G. E., Stokes, J. R., Williamson, A., Fuller, G. G. 2008; 22 (6): 1068-1078

  View details for DOI 10.1016/j.foodhyd.2007.05.014

  View details for Web of Science ID 000255230000012

• Surface rheology of hydrophobically modified PEG polymers associating with a phospholipid monolayer at the air-water interface LANGMUIR Auguste, D. T., Kirkwood, J., Kohn, J., Fuller, G. G., Prud'homme, R. K. 2008; 24 (8): 4056-4064

  Abstract

  Surface rheology of irreversibly bound hydrophobically modified poly(ethylene glycol) (PEG) polymers (HMPEG) on a dipalmitoylphosphatidylcholine (DPPC) monolayer is investigated to determine attributes that may contribute to immune recognition. Previously, three comb-graft polymers (HMPEG136-DP3, HMPEG273-DP2.5, and HMPEG273-DP5) adsorbed on liposomes were examined for their strength of adsorption and protection from complement binding. The data supported an optimal ratio between the hydrophilicity of the PEG polymer and the number of hydrophobic anchors. The HMPEG polymers have different polymer brush thicknesses (4.2-5.9 nm) and levels of cooperativity (2.5-5 hydrophobes). The results indicate that an increased viscous force (above 0.25 mN s/m) at the surface may enable the polymers to shield liposomes from protein interactions. Similar rheological behavior is shown for all polymer architectures at low polymer surface coverage (0.5 mg/m2, in the mushroom regime), whereas at high surface coverage (>0.5 mg/m2, in the brush regime), we observe a structural dependence of the surface viscous forces at 40 mN/m. This threshold correlates with a 92% decrease in complement protein binding for liposomes coated with 1 mg/m2 HMPEG273-DP5. This may suggest that surface viscous forces play a role in reducing complement protein binding.

  View details for DOI 10.1021/la703079p

  View details for Web of Science ID 000254647400053

  View details for PubMedID 18318552

• Analysis of the magnetic rod interfacial stress rheometer JOURNAL OF RHEOLOGY Reynaert, S., Brooks, C. F., Moldenaers, P., Vermant, J., Fuller, G. G. 2008; 52 (1): 261-285

  View details for DOI 10.1122/1.2798238

  View details for Web of Science ID 000252589800011

• Particle bridging between oil and water interfaces LANGMUIR Xu, H., Lask, M., Kirkwood, J., Fuller, G. 2007; 23 (9): 4837-4841

  Abstract

  Particle bridging between a water drop and a flat oil-water interface has been observed when the drop is brought into contact with the interface, leading to the formation of a dense particle monolayer of disc shape (namely, particle disc) that prevents the drop from coalescing into the bulk water phase. Unlike previous observations where particles from opposite interfaces appear to register with each other before bridging, the present experiment demonstrates that the particle registry is not a necessity for bridging. In many cases, the particles from one of the interfaces were repelled away from the contact region, leaving behind the particles from the other interface to bridge the two interfaces. This is confirmed by particle bridging experiments between two interfaces covered with different sized particles, and between a particle-covered interface and a clean interface. The dynamics associated with the growth of the particle disc due to particle bridging follows a power law relationship between the radius of the disc and time: r proportional, variant t0.32+/-0.03. A scaling analysis assuming capillary attraction as the driving force and a hydrodynamic resistance leads to the power law r proportional, variant t1/3, in good agreement with the experiment. In addition, we found that binary mixtures of two different sized particles can undergo phase segregation driven by the particle bridging process.

  View details for DOI 10.1021/la063593l

  View details for Web of Science ID 000245736400024

  View details for PubMedID 17378596

• Mechanical properties and structure of particle coated interfaces: Influence of particle size and bidisperse 2D suspensions LANGMUIR Monteux, C., Jung, E., Fuller, G. G. 2007; 23 (7): 3975-3980

  Abstract

  We report surface pressure-area (Pi-A) isotherms of bidisperse mixtures of anionic polystyrene latex particles at a water/n-decane interface as well as optical photographs of the interface for various compressions and mixture ratios. In the case of mixtures of 3 and 5 mum particles, we observe crystalline layers at high or low concentration ratios, where the "impurity" particles concentrate at the grain boundaries of the crystalline structure. At intermediate ratios, the layers become highly disordered. However, in both cases, we show that the shape of the isotherms remains unchanged. In the case of the mixtures of 9 mum particles with either 3 or 5 mum particles, the smaller particles aggregate around the larger particles through capillary interaction resulting in the formation of large fractal aggregates. At high compression, these layers contain holes that seem very compressible. As a result, the surface pressure isotherms show a smaller surface pressure jump than for other mixtures.

  View details for DOI 10.1021/la063380w

  View details for Web of Science ID 000245012900066

  View details for PubMedID 17305381

• Why inhaling salt water changes what we exhale JOURNAL OF COLLOID AND INTERFACE SCIENCE Watanabe, W., Thomas, M., Clarke, R., Klibanov, A. M., Langer, R., Katstra, J., Fuller, G. G., Griel, L. C., Fiegel, J., Edwards, D. 2007; 307 (1): 71-78

  Abstract

  We find that inhaling salt water diminishes subsequently exhaled biomaterial in man and animals due to reversible stabilization of the airway lining fluid (ALF)/air interface as a novel potential means for control of the spread of airborne infectious disease. The mechanism of this phenomenon relates to charge shielding of mucin or mucin-like macromolecules that consequently undergo gelation; this gelation alters the physical properties of the ALF surface and reduces its breakup. Cations in the nebulized solution and apparent surface viscoelasticity of the ALF (more than any other ALF intrinsic physical property) appear to be responsible for the reduced tendency of the ALF to disintegrate into very small droplets. We confirm these effects in vivo and show their reversibility through nebulization of saline solutions to anesthetized bull calves.

  View details for DOI 10.1016/j.jcis.2006.11.017

  View details for Web of Science ID 000243570400011

  View details for PubMedID 17161415

• Determining the mechanical response of particle-laden fluid interfaces using surface pressure isotherms and bulk pressure measurements of droplets PHYSICAL CHEMISTRY CHEMICAL PHYSICS Monteux, C., Kirkwood, J., Xu, H., Jung, E., Fuller, G. G. 2007; 9 (48): 6344-6350

  Abstract

  The mechanical response of particle-laden fluid interfaces is determined by measuring the internal pressures of particle-coated drops as a function of the drop volume. The particle monolayers undergoing compression-expansion cycles exhibit three distinct states: fluid state, jammed state, and buckled state. The P-V curves are compared to the surface pressure isotherms Pi-A that are measured using a Langmuir trough and a Wilhelmy plate on a flat water-decane interface covered with the same particles. We find that in the fluid and jammed states, the water drop in decane can be described by the Young-Laplace equation. Therefore in these relatively low compression states, the bulk pressure measurements can be used to deduce the interfacial tension of the droplets and yield similar surface pressure isotherms to the ones measured with the Wilhelmy plate. In the buckled state, the internal pressure of the drop yields a zero value, which is consistent with the zero interfacial tension measured with the Wilhelmy plate. Moreover we find that the compressibility in the jammed state does not depend on the particle size.

  View details for DOI 10.1039/b708962g

  View details for Web of Science ID 000251441100008

  View details for PubMedID 18060164

• Lipid-induced beta-amyloid peptide assemblage fragmentation BIOPHYSICAL JOURNAL Widenbrant, M. J., Rajadas, J., Sutardja, C., Fuller, G. G. 2006; 91 (11): 4071-4080

  Abstract

  Alzheimer's disease is the most common cause of dementia and is widely believed to be due to the accumulation of beta-amyloid peptides (Abeta) and their interaction with the cell membrane. Abetas are hydrophobic peptides derived from the amyloid precursor proteins by proteolytic cleavage. After cleavage, these peptides are involved in a self-assembly-triggered conformational change. They are transformed into structures that bind to the cell membrane, causing cellular degeneration. However, it is not clear how these peptide assemblages disrupt the structural and functional integrity of the membrane. Membrane fluidity is one of the important parameters involved in pathophysiology of disease-affected cells. Probing the Abeta aggregate-lipid interactions will help us understand these processes with structural detail. Here we show that a fluid lipid monolayer develop immobile domains upon interaction with Abeta aggregates. Atomic force microscopy and transmission electron microscopy data indicate that peptide fibrils are fragmented into smaller nano-assemblages when interacting with the membrane lipids. Our findings could initiate reappraisal of the interactions between lipid assemblages and Abeta aggregates involved in Alzheimer's disease.

  View details for DOI 10.1529/biophysj.106.085944

  View details for Web of Science ID 000241945600016

  View details for PubMedID 17098805

  View details for PubMedCentralID PMC1635663

• Well-controlled living polymerization of perylene-labeled polyisoprenes and their use in single-molecule Imaging MACROMOLECULES Gavranovic, G. T., Csihony, S., Bowden, N. B., Hawker, C. J., Waymouth, R. M., Moerner, W. E., Fuller, G. G. 2006; 39 (23): 8121-8127

  View details for DOI 10.1021/ma0612475

  View details for Web of Science ID 000241813200046

• Effects of temperature and chemical modification on polymer Langmuir films JOURNAL OF PHYSICAL CHEMISTRY B Gavranovic, G. T., Smith, M. M., Jeong, W., Wong, A. Y., Waymouth, R. M., Fuller, G. G. 2006; 110 (44): 22285-22290

  Abstract

  We previously reported on a rheological study of Langmuir films of poly(tert-butyl methacrylate) (PtBMA), and this work describes further studies on this system. Here, surface pressure-area (Pi-A) isotherms and interfacial shear rheology experiments are performed to better understand the effects of two modifications: varying the temperature between 5 and 40 degrees C and introducing small amounts of carboxylic acid groups by partially hydrolyzing the polymer. Increased temperature produced isotherms with lower plateau surface pressures, Pip, and Pi values shifted to lower areas above Pip. Film properties transition from being primarily viscous to being dominated by elasticity as Pip is crossed for all temperatures studied, even as the value of Pip changes. Increasing the hydrolysis fraction leads to isotherms shifted to lower areas throughout the curve and higher Pip values. Both temperature variation and chemical modification are believed to affect the relative importance of polymer-polymer and polymer-subphase interactions.

  View details for DOI 10.1021/jp063396v

  View details for Web of Science ID 000241729300034

  View details for PubMedID 17078671

• Interfacial rheology and structure of straight-chain and branched hexadecanol mixtures INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH Gavranovic, G. T., Kurtz, R. E., Golemanov, K., Lange, A., Fuller, G. G. 2006; 45 (21): 6880-6884

  View details for DOI 10.1021/ie050965x

  View details for Web of Science ID 000241030700002

• Packing, flipping, and buckling transitions in compressed monolayers of ellipsoidal latex particles LANGMUIR Basavaraj, M. G., Fuller, G. G., Fransaer, J., Vermant, J. 2006; 22 (15): 6605-6612

  Abstract

  The behavior of monolayers of monodisperse prolate ellipsoidal latex particles with the same surface chemistry but varying aspect ratio has been studied experimentally. Particle monolayers at an air-water interface were subjected to compression in a Langmuir trough. When surface pressure measurements and microscopy observations were combined, possible structural transitions were evaluated. Ellipsoids of a sufficiently large aspect ratio display a less abrupt increase in the compression isotherms than spherical particles. Microscopic observations reveal that a sequence of transitions is responsible for this more gradual increase of the surface pressure. When a percolating aggregate network is used as the starting point, locally ordered regions appear progressively. When it reaches a certain surface pressure, the system "jams", and in-plane rearrangements are no longer possible at this point. A highly localized yielding of the particle network is observed. The compressional stress is relieved by flipping the ellipsoids into an upright position and by expelling particles from the monolayer. The latter does not occur for spherical particles with similar dimensions and surface chemistry. In the final stage of compression, buckling of the monolayer as a whole was observed. The effect of aspect ratio on the pressure area isotherms and on the obtained percolation and packing thresholds was quantified.

  View details for DOI 10.1021/la060465o

  View details for Web of Science ID 000238926000022

  View details for PubMedID 16831003

• Interfacial rheology and structure of straight-chain and branched fatty alcohol mixtures LANGMUIR Kurtz, R. E., Lange, A., Fuller, G. G. 2006; 22 (12): 5321-5327

  Abstract

  Langmuir monolayers of mixtures of straight-chain and branched molecules of hexadecanol and eicosanol were studied using surface pressure-area isotherms, Brewster angle microscopy, and interfacial rheology measurements. For hexadecanol mixtures below 30% branched molecules, the isotherms show a lateral shift to a decreasing area proportional to the fraction of straight chains. Above a 30% branched fraction, the isotherms are no longer identical in shape. The surface viscosities of both straight and mixed monolayers exhibit a maximum in the condensed untilted LS phase at pi = 20 mN/m. Adding branched chains results in a nonmonotonic increase in surface viscosity, with the maximum near 12% branched hexadecanol. A visualization of these immiscible monolayers using Brewster angle microscopy in the liquid condensed phase shows the formation of discrete domains that initially increase in number density and then decrease with increasing surface pressure. Eicosanol mixtures exhibit different rheological and structural behavior from hexadecanol mixtures. The addition of branched chains results in a lateral shift to increasing area, proportional to the fraction and projected area of both straight and branched chains. A phase transition is seen for all mixtures, including pure straight chains, at pi = 15 mN/m up to 50% branched chains. A second transition is seen at pi = 25 mN/m when the isotherms cross over. Above this transition, the isotherms shift in the reverse direction with increasing branched fraction. The surface viscosities of both straight and mixed monolayers show a maximum in the L2' phase near pi = 5 mN/m. The surface viscosity is constant for low branched fractions and decays beyond 15% branched chains.

  View details for DOI 10.1021/la060290i

  View details for Web of Science ID 000237921100023

  View details for PubMedID 16732659

• Shear surface rheology of poly(N-isopropylacrylamide) adsorbed layers at the air-water interface MACROMOLECULES Monteux, C., Mangeret, R., Laibe, G., Freyssingeas, E., Bergeron, V., Fuller, G. 2006; 39 (9): 3408-3414

  View details for DOI 10.1021/ma052552d

  View details for Web of Science ID 000237390100043

• Shape and buckling transitions in solid-stabilized drops LANGMUIR Xu, H., Melle, S., Golemanov, K., Fuller, G. 2005; 21 (22): 10016-10020

  Abstract

  We study shape and buckling transitions of particle-laden sessile and pendant droplets that are forced to shrink in size. Monodisperse polystyrene particles were placed at the interface between water and decane at conditions that are known to produce hexagonal, crystalline arrangements on flat interfaces. As the volumes of the drops are reduced, the surface areas are likewise diminished. This effectively compresses the particle monolayer coating and induces a transition from a fluid film to a solid film. Since the particles are firmly attached to the interface by capillary forces, the shape transitions are reversible and shape/volume curves are the same for drainage and inflation. Measurements of the internal pressure of the drops reveal a strong transition in this variable as the buckling transition is approached.

  View details for DOI 10.1021/la0507378

  View details for Web of Science ID 000232731700029

  View details for PubMedID 16229521

• Optics of sheared liquid-crystal polarizer based on aqueous dispersion of dichroic-dye nano-aggregates JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY Paukshto, M., Fuller, G., Michailov, A., Remizov, S. 2005; 13 (9): 765-772

  View details for Web of Science ID 000236283000010

• Lung surfactant gelation induced by epithelial cells exposed to air pollution or oxidative stress AMERICAN JOURNAL OF RESPIRATORY CELL AND MOLECULAR BIOLOGY Anseth, J. W., Goffin, A. J., Fuller, G. G., Ghio, A. J., Kao, P. N., Upadhyay, D. 2005; 33 (2): 161-168

  Abstract

  Lung surfactant lowers surface tension and adjusts interfacial rheology to facilitate breathing. A novel instrument, the interfacial stress rheometer (ISR), uses an oscillating magnetic needle to measure the shear viscosity and elasticity of a surfactant monolayer at the air-water interface. The ISR reveals that calf lung surfactant, Infasurf, exhibits remarkable fluidity, even when exposed to air pollution residual oil fly ash (ROFA), hydrogen peroxide (H2O2), or conditioned media from resting A549 alveolar epithelial cells (AEC). However, when Infasurf is exposed to a subphase of the soluble fraction of ROFA- or H2O2-treated AEC conditioned media, there is a prominent increase in surfactant elasticity and viscosity, representing two-dimensional gelation. Surfactant gelation is decreased when ROFA-AEC are pretreated with inhibitors of cellular reactive oxygen species (ROS), or with a mitochondrial anion channel inhibitor, as well as when A549-rho0 cells that lack mitochondrial DNA and functional electron transport are investigated. These results implicate both mitochondrial and nonmitochondrial ROS generation in ROFA-AEC-induced surfactant gelation. A549 cells treated with H2O2 demonstrate a dose-dependent increase in lung surfactant gelation. The ISR is a unique and sensitive instrument to characterize surfactant gelation induced by oxidatively stressed AEC.

  View details for DOI 10.1165/rcmb.2004-0365OC

  View details for PubMedID 15860796

• Two-dimensional melts: Polymer chains at the air-water interface MACROMOLECULES Gavranovic, G. T., Deutsch, J. M., Fuller, G. G. 2005; 38 (15): 6672-6679

  View details for DOI 10.1021/ma050061n

  View details for Web of Science ID 000230627000057

• Pickering emulsions with controllable stability LANGMUIR Melle, S., Lask, M., Fuller, G. G. 2005; 21 (6): 2158-2162

  Abstract

  We prepare solid-stabilized emulsions using paramagnetic particles at an oil/water interface that can undergo macroscopic phase separation upon application of an external magnetic field. A critical field strength is found for which emulsion droplets begin to translate into the continuous-phase fluid. At higher fields, the emulsions destabilize, leading to a fully phase-separated system. This effect is reversible, and long-term stability can be recovered by remixing the components with mechanical agitation.

  View details for DOI 10.1021/la047691n

  View details for Web of Science ID 000227578700012

  View details for PubMedID 15752002

• Investigation of shear-banding structure in wormlike micellar solution by point-wise flow-induced birefringence measurements JOURNAL OF RHEOLOGY Lee, J. Y., Fuller, G. G., Hudson, N. E., Yuan, X. F. 2005; 49 (2): 537-550

  View details for DOI 10.1122/1.1849179

  View details for Web of Science ID 000227848700011

• Rheological behavior of precursor PPV monolayers LANGMUIR Luinge, J. W., Nijboer, G. W., Hagting, J. G., Vorenkamp, E. J., Fuller, G. G., Schouten, A. J. 2004; 20 (26): 11517-11522

  Abstract

  The rheological behavior of different precursor poly(p-phenylene vinylene) (prec-PPV) monolayers at the air-water interface was investigated using an interfacial stress rheometer (ISR). This device nicely reveals a transition of the precursor poly(2,5-dimethoxy-1,4 phenylene vinylene) (prec-DMePPV) monolayer from Newtonian to elastic behavior with increasing surface pressure. The transition is accompanied by an increase in the modulus. This behavior coincides with the coagulation of different 2D condensed domains as revealed by Brewster angle microscopy (BAM). However, partly converted prec-DMePPV monolayers show elastic behavior even at low surface pressures, although a sudden increase of the moduli does occur. This phenomenon is attributed to enhanced hydrophobic interactions between the conjugated moieties in the partly converted polymers. The latter also explains the stretching behavior of the partly converted prec-DMePPV upon transfer in Langmuir-Blodgett-type vertical dipping. The increase of the moduli which is observed is much more gradual in the precursor poly(2,5-dibutoxy-1,4-phenylene vinylene), prec-DBuPPV, a monolayer which is in agreement with the expected expanded state of the latter monolayer.

  View details for DOI 10.1021/la048234+

  View details for Web of Science ID 000225816800035

  View details for PubMedID 15595778

• Shear and dilatational relaxation mechanisms of globular and flexible proteins at the hexadecane/water interface LANGMUIR Freer, E. M., Yim, K. S., Fuller, G. G., Radke, C. J. 2004; 20 (23): 10159-10167

  Abstract

  Proteins adsorbed at fluid/fluid interfaces influence many phenomena: food emulsion and foam stability (Murray et al. Langmuir 2002, 18, 9476 and Borbas et al. Colloids Surf., A 2003, 213, 93), two-phase enzyme catalysis (Cascao-Pereira et al. Biotechnol. Bioeng. 2003, 83, 498; 2002, 78, 595), human lung function (Lunkenheimer et al. Colloids Surf., A 1996, 114, 199; Wustneck et al.; and Banerjee et al. 2000, 15, 14), and cell membrane mechanical properties (Mohandas et al. 1994, 23, 787). Time scales important to these phenomena are broad, necessitating an understanding of the dynamics of biological macromolecules at interfaces. We utilize interfacial shear and dilatational deformations to study the rheology of a globular protein, lysozyme, and a disordered protein, beta-casein, at the hexadecane/water interface. Linear viscoelastic properties are measured using small amplitude oscillatory flow, stress relaxation after a sudden dilatational displacement, and shear creep response to probe the rheological response over broad experimental time scales. Our studies of lysozyme and beta-casein reveal that the interfacial dissipation mechanisms are strongly coupled to changes in the protein structure upon and after adsorption. For beta-casein, the interfacial response is fluidlike in shear deformation and is dominated by interfacial viscous dissipation, particularly at low frequencies. Conversely, the dilatational response of beta-casein is dominated by diffusion dissipation at low frequencies and viscous dissipation at higher frequencies (i.e., when the experimental time scale is faster than the characteristic time for diffusion). For lysozyme in shear deformation, the adsorbed protein layer is primarily elastic with only a weak frequency dependence. Similarly, the interfacial dilatational moduli change very little with frequency. In comparison to beta-casein, the frequency response of lysozyme does not change substantially after washing the protein from the bulk solution. Apparently, it is the irreversibly adsorbed fraction that dominates the dynamic rheological response for lysozyme. Using stress relaxation after a sudden dilatational displacement and shear creep response, the characteristic time of relaxation was found to be 1000 s in both modes of deformation. The very long relaxation time for lysozyme likely results from the formation of a glassy interfacial network. This network develops at high interfacial concentrations where the molecules are highly constrained because of conformation changes that prevent desorption.

  View details for DOI 10.1021/la0485226

  View details for Web of Science ID 000224981600043

  View details for PubMedID 15518508

• Shear and dilational surface rheology of oppositely charged polyelectrolyte/surfactant microgels adsorbed at the air-water interface. Influence on foam stability JOURNAL OF PHYSICAL CHEMISTRY B Monteux, C., Fuller, G. G., Bergeron, V. 2004; 108 (42): 16473-16482

  View details for DOI 10.1021/jp047462+

  View details for Web of Science ID 000224539100023

• Connect the drops: Using solids as adhesives for liquids LANGMUIR Stancik, E. J., Fuller, G. G. 2004; 20 (12): 4805-4808

  Abstract

  Colloidal particles are shown to be capable of developing adhesion between liquid phases through a bridging mechanism by which intervening, micrometer-scaled, fluid films are stabilized. Particle dynamics leading to the assembly of the stabilizing structure are discussed. Models for the resulting adhesive force are developed from considerations of both interface shape perturbation and the force applied by surface tension on an individual particle. Finally, predictions from these models are compared to direct measurements of the forces that arise during the separation of adhering interfaces. Such comparisons lead to a novel method for determining the three-phase contact angle inherent to particles residing at fluid interfaces.

  View details for DOI 10.1021/la049778e

  View details for Web of Science ID 000221846000006

  View details for PubMedID 15984234

• Development characteristics of drag-reducing surfactant solution flow in a duct RHEOLOGICA ACTA Suzuki, H., Fuller, G. G., Nakayama, T., Usui, H. 2004; 43 (3): 232-239

  View details for DOI 10.1007/s00397-003-0335-6

  View details for Web of Science ID 000221192600003

• Interfacial rheology of globular and flexible proteins at the hexadecane/water interface: Comparison of shear and dilatation deformation JOURNAL OF PHYSICAL CHEMISTRY B Freer, E. M., Yim, K. S., Fuller, G. G., Radke, C. J. 2004; 108 (12): 3835-3844

  View details for DOI 10.1021/jp037236k

  View details for Web of Science ID 000220323500026

• Influence of subphase conditions on interfacial viscoelastic properties of synthetic lipids with gentiobiose head groups JOURNAL OF PHYSICAL CHEMISTRY B Tanaka, M., Schiefer, S., Gege, C., Schmidt, R. R., Fuller, G. G. 2004; 108 (10): 3211-3214

  View details for DOI 10.1021/jp0367934

  View details for Web of Science ID 000220093900016

• Coalescence of particle-laden fluid interfaces LANGMUIR Stancik, E. J., Kouhkan, M., Fuller, G. G. 2004; 20 (1): 90-94

  Abstract

  Colloidal particles are capable of stabilizing emulsions and, thus, slowing or preventing their complete breakdown into phase-separated systems. Direct observations of the dynamics of such particles on both water and oil droplets are reported as two colloid-laden interfaces are brought into contact with each other. As coalescence proceeds, the complementary systems, representing oil-in-water and water-in-oil emulsions, exhibit contrasting mechanisms for the formation of ring and disk structures by the particles as they serve to temporarily stabilize the approaching surfaces. An explanation of such behavior leads to a better understanding of the stabilization and breaking mechanisms of so-called Pickering emulsions.

  View details for DOI 10.1021/la0356093

  View details for Web of Science ID 000187754400018

  View details for PubMedID 15745004

• Dynamic transitions and oscillatory melting of a two-dimensional crystal subjected to shear flow JOURNAL OF RHEOLOGY Stancik, E. J., Hawkinson, A. L., Vermant, J., Fuller, G. G. 2004; 48 (1): 159-173

  View details for DOI 10.1122/1.1631425

  View details for Web of Science ID 000187952400010

• Microstructure evolution in magnetorheological suspensions governed by Mason number PHYSICAL REVIEW E Melle, S., Calderon, O. G., Rubio, M. A., Fuller, G. G. 2003; 68 (4)

  Abstract

  The spatiotemporal evolution of field-induced structures in very dilute polarizable colloidal suspensions subject to rotating magnetic fields has been experimentally studied using video microscopy. We found that there is a crossover Mason number (ratio of viscous to magnetic forces) above which the rotation of the field prevents the particle aggregation to form chains. Therefore, at these high Mason numbers, more isotropic clusters and isolated particles appear. The same behavior was also found in recent scattering dichroism experiments developed in more concentrated suspensions, which seems to indicate that the dynamics does not depend on the volume fraction. Scattering dichroism experiments have been used to study the role played by the volume fraction in suspensions with low concentration. As expected, we found that the crossover Mason number does not depend on the volume fraction. Brownian particle dynamics simulations are also reported, showing good agreement with the experiments.

  View details for DOI 10.1103/PhysRevE.68.041503

  View details for Web of Science ID 000186569100030

  View details for PubMedID 14682943

• Interfacial rheology of graft-type polymeric siloxane surfactants LANGMUIR Anseth, J. W., Bialek, A., Hill, R. M., Fuller, G. G. 2003; 19 (16): 6349-6356

  View details for DOI 10.1021/la0269614

  View details for Web of Science ID 000184526600004

• Shearing or compressing a soft glass in 2D: Time-concentration superposition PHYSICAL REVIEW LETTERS Cicuta, P., Stancik, E. J., Fuller, G. G. 2003; 90 (23)

  Abstract

  We report surface shear rheological measurements on dense insoluble monolayers of micron sized colloidal spheres at the oil/water interface and of the protein beta-lactoglobulin at the air/water surface. As expected, the elastic modulus shows a changing character in the response, from a viscous liquid towards an elastic solid as the concentration is increased, and a change from elastic to viscous as the shear frequency is increased. Surprisingly, above a critical packing fraction, the complex elastic modulus curves measured at different concentrations can be superposed to form a master curve. This provides a powerful tool for the extrapolation of the material response function outside the experimentally accessible frequency range. The results are discussed in relation to recent experiments on bulk systems, and indicate that these two-dimensional monolayers should be regarded as being close to a soft glass state.

  View details for DOI 10.1103/PhysRevLett.90.236101

  View details for Web of Science ID 000183483500034

  View details for PubMedID 12857273

• Influence of phase transition and photoisomerization on interfacial rheology PHYSICAL REVIEW E Yim, K. S., Fuller, G. G. 2003; 67 (4)

  Abstract

  This paper presents the shear responses and interfacial rheology of photosensitive monolayers. Langmuir films of a fatty acid containing an azobenzene moiety that can undergo trans-cis photoisomerization have been investigated for their structural and dynamical properties. The cis conformation produces a structureless, Newtonian film that cannot be oriented by surface flows. Transforming the molecule to the trans configuration produces a well-packed film that responds to flow with an anisotropic and non-Newtonian character. The trans state supports two separate phases, a low-pressure phase where the azobenzene group is free to rotate, and a high-pressure phase where this moiety is frozen in place.

  View details for DOI 10.1103/PhysRevE.67.041601

  View details for Web of Science ID 000182824400034

  View details for PubMedID 12786367

• Component stress-strain behavior and small-angle neutron scattering investigation of stereoblock elastomeric polypropylene MACROMOLECULES Wiyatno, W., Fuller, G. G., Pople, J. A., Gast, A. P., Chen, Z. R., Waymouth, R. M., Myers, C. L. 2003; 36 (4): 1178-1187

  View details for DOI 10.1021/na020477q

  View details for Web of Science ID 000181117200032

• Structure and dynamics of particle monolayers at a liquid-liquid interface subjected to shear flow General Meeting on Non-Equilibrium Behaviour of Colloidal Dispersions Stancik, E. J., Gavranovic, G. T., Widenbrant, M. J., Laschitsch, A. T., Vermant, J., Fuller, G. G. ROYAL SOC CHEMISTRY. 2003: 145–156

  Abstract

  The effect of shear flow on the structure and dynamics of monodisperse spherical polystyrene particles suspended at the interface between decane and water was observed. While undisturbed, the particles arrange themselves on a hexagonal lattice due to strong dipole-dipole repulsion resulting from ionizable sulfate groups on their surfaces. As the interface is subjected to shear flow, however, the lattice adopts a new semi-ordered, anisotropic state for which two distinct regimes are observed. At low particle concentrations or high shear rates, nearest neighbors in the lattice align in the flow direction and create strings of particles that slip past each other fairly readily. This results in a stretching of the overall structure and achievement of a steady state orientation in the system. In contrast, at high concentrations or low shear rates, the interparticle forces gain importance and tend to keep the particles more strongly in their lattice positions. As a result, domains within the lattice are forced to rotate, thus giving rise to movement of particles perpendicular to the flow direction. Thus a rotation, in addition to stretching, of the structure is apparent in this case.

  View details for Web of Science ID 000180338300012

  View details for PubMedID 12638860

• Microstructural changes of a binary polymer blend in simple shear flow across the phase boundary 74th Annual Meeting of the Society-of-Rheology Vlassopoulos, D., Terakawa, T., Fuller, G. G. JOURNAL RHEOLOGY AMER INST PHYSICS. 2003: 143–61

  View details for DOI 10.1122/1.1530616

  View details for Web of Science ID 000180360900009

• Dynamic response of stereoblock elastomeric polypropylene studied by rheooptics and X-ray scattering. 2. Orthogonally oriented crystalline chains MACROMOLECULES Wiyatno, W., Pople, J. A., Gast, A. P., Waymouth, R. M., Fuller, G. G. 2002; 35 (22): 8498-8508

  View details for DOI 10.1021/ma020262g

  View details for Web of Science ID 000178738000034

• Dynamic response of stereoblock elastomeric polypropylene studied by rheooptics and X-ray scattering. 1. Influence of isotacticity MACROMOLECULES Wiyatno, W., Pople, J. A., Gast, A. P., Waymouth, R. M., Fuller, G. G. 2002; 35 (22): 8488-8497

  View details for DOI 10.1021/ma020261o

  View details for Web of Science ID 000178738000033

• Surface rheological transitions in Langmuir monolayers of bi-competitive fatty acids LANGMUIR Yim, K. S., Rahaii, B., Fuller, G. G. 2002; 18 (17): 6597-6601

  View details for DOI 10.1021/la025608v

  View details for Web of Science ID 000177487600021

• Development of a double-beam rheo-optical analyzer for full tensor measurement of optical anisotropy in complex fluid flow RHEOLOGICA ACTA Takahashi, T., Shirakashi, M., Miyamoto, K., Fuller, G. G. 2002; 41 (5): 448-455

  View details for DOI 10.1007/s00397-002-0226-2

  View details for Web of Science ID 000177862000007

• Chain rotational dynamics in MR suspensions 8th International Conference on Electro-Rheological Fluids and Magneto-Rheological Suspensions Melle, S., Calderon, O. G., Rubio, M. A., Fuller, G. G. WORLD SCIENTIFIC PUBL CO PTE LTD. 2002: 2293–99

  View details for Web of Science ID 000177280100005

• Structure and dynamics of particle monolayers at a liquid-liquid interface subjected to extensional flow LANGMUIR Stancik, E. J., Widenbrant, M. J., Laschitsch, A. T., Vermant, J., Fuller, G. G. 2002; 18 (11): 4372-4375

  View details for DOI 10.1021/la015723q

  View details for Web of Science ID 000175801600031

• Morphology of thermoplastic elastomers: Elastomeric polypropylene MACROMOLECULES Schonherr, H., Wiyatno, W., Pople, J., Frank, C. W., Fuller, G. G., Gast, A. P., Waymouth, R. M. 2002; 35 (7): 2654-2666

  View details for DOI 10.1021/ma010959m

  View details for Web of Science ID 000174559600037

• Surface shear rheology of a polymerizable lipopolymer monolayer LANGMUIR Brooks, C. F., Thiele, J., Frank, C. W., O'Brien, D. F., Knoll, W., Fuller, G. G., Robertson, C. R. 2002; 18 (6): 2166-2173

  View details for DOI 10.1021/la0112312

  View details for Web of Science ID 000174403000032

• Polarizable particle aggregation under rotating magnetic fields using scattering dichroism JOURNAL OF COLLOID AND INTERFACE SCIENCE Melle, S., Calderon, O. G., Fuller, G. G., Rubio, M. A. 2002; 247 (1): 200-209

  Abstract

  We used scattering dichroism to study the dynamics of dipolar chains induced in magnetorheological suspensions under rotating magnetic fields. Both the dichroism (proportional to the total number of aggregated particles) and the phase lag show different behavior below and above a cross-over frequency. The cross-over frequency depends linearly on both the square of the magnetization and the inverse of the viscosity. The Mason number (ratio of viscous to magnetic forces) governs the dynamics. Therefore, there is a cross-over Mason number below which the dichroism remains almost constant and above which the rotation of the field prevents the particle aggregation process from taking place. Our experimental results have been compared with particle dynamics simulations showing good agreement.

  View details for DOI 10.1006/jcis.2001.8087

  View details for Web of Science ID 000173998300024

  View details for PubMedID 16290457

• Rotational dynamics in dipolar colloidal suspensions: video microscopy experiments and simulations results JOURNAL OF NON-NEWTONIAN FLUID MECHANICS Melle, S., Calderon, O. G., Rubio, M. A., Fuller, G. G. 2002; 102 (2): 135-148

  View details for Web of Science ID 000173617600003

• Rheology of glycocalix model at air/water interface PHYSICAL CHEMISTRY CHEMICAL PHYSICS Schneider, M. F., Lim, K., Fuller, G. G., Tanaka, M. 2002; 4 (10): 1949-1952

  View details for DOI 10.1039/b110631g

  View details for Web of Science ID 000175326100039

• Shear-banding structure orientated in the vorticity direction observed for equimolar micellar solution RHEOLOGICA ACTA Fischer, P., Wheeler, E. K., Fuller, G. G. 2002; 41 (1-2): 35-44

  View details for Web of Science ID 000173682600004

• Electrophoresis of DNA adsorbed to a cationic supported bilayer LANGMUIR OLSON, D. J., Johnson, J. M., Patel, P. D., Shaqfeh, E. S., Boxer, S. G., Fuller, G. G. 2001; 17 (23): 7396-7401

  View details for Web of Science ID 000172123700036

• Isotropic-nematic phase transitions of lyotropic, two-dimensional liquid crystalline polymer solutions MACROMOLECULES Yim, K. S., Fuller, G. G., Datko, A., Eisenbach, C. D. 2001; 34 (20): 6972-6977

  View details for Web of Science ID 000171199300019

• Time scaling regimes in aggregation of magnetic dipolar particles: Scattering dichroism results PHYSICAL REVIEW LETTERS Melle, S., Rubio, M. A., Fuller, G. G. 2001; 87 (11)

  Abstract

  We report experimental results on the aggregation kinetics in magnetorheological fluids subject to a constant uniaxial magnetic field using the technique of scattering dichroism. We show that the number of aggregated particles displays a long-time power-law dependence with exponents that correspond to two different aggregation regimes. These regimes coincide with 3D and 1D-like aggregation. We also derive the values of both time exponents for the number of aggregated particles.

  View details for DOI 10.1103/PhysRevLett.87.115501

  View details for Web of Science ID 000170984600026

  View details for PubMedID 11531533

• Two-dimensional physical networks of lipopolymers at the air/water interface: Correlation of molecular structure and surface rheological behavior LANGMUIR Naumann, C. A., Brooks, C. F., Fuller, G. G., Lehmann, T., Ruhe, J., Knoll, W., Kuhn, P., Nuyken, O., Frank, C. W. 2001; 17 (9): 2801-2806

  View details for DOI 10.1021/la000778y

  View details for Web of Science ID 000168373000041

• Rheological properties of lipopolymer-phospholipid mixtures at the air-water interface: A novel form of two-dimensional physical gelation MACROMOLECULES Naumann, C. A., Brooks, C. F., Wiyatno, W., Knoll, W., Fuller, G. G., Frank, C. W. 2001; 34 (9): 3024-3032

  View details for DOI 10.1021/ma0009810

  View details for Web of Science ID 000168236600041

• Rheooptical determination of aspect ratio and polydispersity of nonspherical particles AICHE JOURNAL Vermant, J., Yang, H., Fuller, G. G. 2001; 47 (4): 790-798

  View details for Web of Science ID 000168015200004

• Orientation dynamics of magnetorheological fluids subject to rotating external fields 7th International Conference on Electro-Rheological Fluids and Magneto-Rheological Suspension Melle, S., Rubio, M. A., Fuller, G. G. WORLD SCIENTIFIC PUBL CO PTE LTD. 2001: 758–66

  View details for Web of Science ID 000168832300025

• Two-dimensional physical networks of lipopolymers at the air/water interface 3rd International Conference on Polymer-Solvent Complexes and Intercalates Frank, C. W., Naumann, C. A., Knoll, W., Brooks, C. F., Fuller, G. G. WILEY-V C H VERLAG GMBH. 2001: 1–12

  View details for Web of Science ID 000168550400002

• Birefringence and stress growth in uniaxial extension of polymer solutions JOURNAL OF NON-NEWTONIAN FLUID MECHANICS Sridhar, T., Nguyen, D. A., Fuller, G. G. 2000; 90 (2-3): 299-315

  View details for Web of Science ID 000086868200008

• Surface pressure-induced isotropic-nematic transition in polymer monolayers - Effect of solvent molecules LANGMUIR Yim, K. S., Brooks, C. F., Fuller, G. G., Datko, A., Eisenbach, C. D. 2000; 16 (9): 4319-4324

  View details for Web of Science ID 000086909500041

• Non-Newtonian rheology of liquid crystalline polymer monolayers LANGMUIR Yim, K. S., Brooks, C. F., Fuller, G. G., Winter, D., Eisenbach, C. D. 2000; 16 (9): 4325-4332

  View details for Web of Science ID 000086909500042

• On the existence of a stress-optical relation in immiscible polymer blends LANGMUIR Van Puyvelde, P., Moldenaers, P., Mewis, J., Fuller, G. G. 2000; 16 (8): 3740-3747

  View details for Web of Science ID 000086484100024

• Structure and dynamics of magnetorheological fluids in rotating magnetic fields Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics Melle, S., Fuller, G. G., Rubio, M. A. 2000; 61 (4 Pt B): 4111-7

  Abstract

  We report on the orientation dynamics and aggregation processes of magnetorheological fluids subject to rotating magnetic fields using the technique of scattering dichroism. In the presence of stationary fields we find that the mean length of the field-induced aggregates reaches a saturation value due to finite-size effects. When a rotating field is imposed, we see the chains rotate with the magnetic field frequency (synchronous regime) but with a retarded phase angle for all the rotational frequencies applied. However, two different behaviors are found below or above a critical frequency f(c). Within the first regime (low frequency values) the size of the aggregates remains almost constant, while at high frequencies this size becomes shorter due to hydrodynamic drag. Experimental results have been reproduced by a simple model considering a torque balance on the chainlike aggregates.

  View details for PubMedID 11088205

• Structure and dynamics of magnetorheological fluids in rotating magnetic fields PHYSICAL REVIEW E Melle, S., Fuller, G. G., Rubio, M. A. 2000; 61 (4): 4111-4117

  View details for Web of Science ID 000086597300017

• Contraction and expansion flows of Langmuir monolayers JOURNAL OF NON-NEWTONIAN FLUID MECHANICS OLSON, D. J., Fuller, G. G. 2000; 89 (1-2): 187-207

  View details for Web of Science ID 000084634400008

• Phase behavior and flow properties of "hairy-rod" monolayers LANGMUIR Fischer, P., Brooks, C. F., Fuller, G. G., Ritcey, A. M., Xiao, Y. F., Rahem, T. 2000; 16 (2): 726-734

  View details for Web of Science ID 000084890100067

• Transient birefringence of elastomeric polypropylene subjected to step shear strain MACROMOLECULES Carlson, E. D., Fuller, G. G., Waymouth, R. M. 1999; 32 (24): 8094-8099

  View details for Web of Science ID 000084020000020

• Component relaxation processes within elastomeric polypropylene MACROMOLECULES Carlson, E. D., Fuller, G. G., Waymouth, R. M. 1999; 32 (24): 8100-8106

  View details for Web of Science ID 000084020000021

• Viscoelastic properties of lipopolymers at the air-water interface: A combined interfacial stress rheometer and film balance study LANGMUIR Naumann, C. A., Brooks, C. F., Fuller, G. G., Knoll, W., Frank, C. W. 1999; 15 (22): 7752-7761

  View details for Web of Science ID 000083501000051

• Elastomeric polypropylenes from unbridged 2-phenylindene zirconocene catalysts: Temperature dependence of crystallinity and relaxation properties MACROMOLECULES Hu, Y. R., Carlson, E. D., Fuller, G. G., Waymouth, R. M. 1999; 32 (10): 3334-3340

  View details for Web of Science ID 000080441900021

• Characterization of the flow properties of sodium carboxymethylcellulose via mechanical and optical techniques RHEOLOGICA ACTA Kulicke, W. M., Reinhardt, U., Fuller, G. G., Arendt, O. 1999; 38 (1): 26-33

  View details for Web of Science ID 000080516600003

• An interfacial stress rheometer to study rheological transitions in monolayers at the air-water interface LANGMUIR Brooks, C. F., Fuller, G. G., Frank, C. W., Robertson, C. R. 1999; 15 (7): 2450-2459

  View details for Web of Science ID 000079541000033

• Large-scale bundle ordering in sterically stabilized latices JOURNAL OF COLLOID AND INTERFACE SCIENCE Vermant, J., Raynaud, L., Mewis, J., Ernst, B., Fuller, G. G. 1999; 211 (2): 221-229

  View details for Web of Science ID 000079014100006

• Dynamic light scattering during shear: measurements of diffusion coefficients POLYMER Rusu, D., Genoe, D., Van Puyvelde, P., Peuvrel-Disdier, E., NAVARD, P., Fuller, G. G. 1999; 40 (6): 1353-1357

  View details for Web of Science ID 000077442200001

• Electric field-induced component dynamics in a binary liquid crystal mixture studied using two-dimensional Raman scattering LIQUID CRYSTALS Huang, K., Fuller, G. G. 1999; 26 (1): 1-7

  View details for Web of Science ID 000078153700001

• Two-dimensional Raman study of the submolecular, electric field-induced reorientation of a nematic liquid crystal LIQUID CRYSTALS Huang, K., Fuller, G. G. 1998; 25 (6): 745-755

  View details for Web of Science ID 000077344000011

• Rheological and thermal properties of elastomeric polypropylene MACROMOLECULES Carlson, E. D., Krejchi, M. T., Shah, C. D., Terakawa, T., Waymouth, R. M., Fuller, G. G. 1998; 31 (16): 5343-5351

  View details for Web of Science ID 000075347600020

• The dynamics of two dimensional polymer nematics International Conference on the Dynamics of Polymeric Liquids Maruyama, T., Fuller, G. G., Grosso, M., Maffettone, P. L. ELSEVIER SCIENCE BV. 1998: 233–47

  View details for Web of Science ID 000073289800013

• Anisotropy and orientation of the microstructure in viscous emulsions during shear flow LANGMUIR Vermant, J., Van Puyvelde, P., Moldenaers, P., Mewis, J., Fuller, G. G. 1998; 14 (7): 1612-1617

  View details for Web of Science ID 000072914700021

• Orientation in a fatty acid monolayer: Effect of flow type LANGMUIR Maruyama, T., Lauger, J., Fuller, G. G., Frank, C. W., Robertson, C. R. 1998; 14 (7): 1836-1845

  View details for Web of Science ID 000072914700050

• Time-periodic flow induced structures and instabilities in a viscoelastic surfactant solution JOURNAL OF NON-NEWTONIAN FLUID MECHANICS Wheeler, E. K., Fischer, P., Fuller, G. G. 1998; 75 (2-3): 193-208

  View details for Web of Science ID 000072697200004

• Rheo-optical studies of shear-induced structures in semidilute polystyrene solutions MACROMOLECULES Kume, T., Hashimoto, T., Takahashi, T., FULLER, G. B. 1997; 30 (23): 7232-7236

  View details for Web of Science ID A1997YH24700029

• Branched viscoelastic surfactant solutions and their response to elongational flow RHEOLOGICA ACTA Fischer, P., Fuller, G. G., Lin, Z. C. 1997; 36 (6): 632-638

  View details for Web of Science ID 000071448700005

• Electric field studies of liquid crystal droplet suspensions LIQUID CRYSTALS DEGROOT, E. M., Fuller, G. G. 1997; 23 (1): 113-126

  View details for Web of Science ID A1997XH13500013

• Optical rheometry of complex fluid interfaces CURRENT OPINION IN COLLOID & INTERFACE SCIENCE Fuller, G. G. 1997; 2 (2): 153-157

  View details for Web of Science ID A1997WY18700005

• Extensional flow of a two-dimensional polymer liquid crystal MACROMOLECULES Maffettone, P. L., Grosso, M., FRIEDENBERG, M. C., Fuller, G. G. 1996; 29 (26): 8473-8478

  View details for Web of Science ID A1996VY91500028

• Deformation and relaxation processes of mono- and bilayer domains of liquid crystalline Langmuir films on water LANGMUIR Lauger, J., Robertson, C. R., Frank, C. W., Fuller, G. G. 1996; 12 (23): 5630-5635

  View details for Web of Science ID A1996VT71800024

• Polarization-modulated Raman scattering measurements of nematic liquid crystal orientation REVIEW OF SCIENTIFIC INSTRUMENTS Huang, K., Archer, L. A., Fuller, G. G. 1996; 67 (11): 3924-3930

  View details for Web of Science ID A1996VT18800020

• Flow-induced molecular orientation of a Langmuir film SCIENCE Maruyama, T., Fuller, G., Frank, C., Robertson, C. 1996; 274 (5285): 233-235

  View details for Web of Science ID A1996VM67100039

• The dynamic birefringence of high polymers - Comments JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS Fuller, G. G. 1996; 34 (9): 1505-1506

  View details for Web of Science ID A1996UT32600003

• Stress tensor measurement using birefringence in oblique transmission RHEOLOGICA ACTA Takahashi, T., Fuller, G. 1996; 35 (4): 297-302

  View details for Web of Science ID A1996VH84900001

• Direct visualization of flow-induced anisotropy in a fatty acid monolayer LANGMUIR FRIEDENBERG, M. C., Fuller, G. G., Frank, C. W., Robertson, C. R. 1996; 12 (6): 1594-1599

  View details for Web of Science ID A1996UB63400031

• Structure and rheology of wormlike micelles RHEOLOGICA ACTA Wheeler, E. K., IZU, P., Fuller, G. G. 1996; 35 (2): 139-149

  View details for Web of Science ID A1996UD86100007

• In-situ studies of flow-induced phenomena in Langmuir monolayers International Symposium on Ultra Materials for Picotransfer Maruyama, T., Friedenberg, M., Fuller, G. G., Frank, C. W., Robertson, C. R., Ferencz, A., Wegner, G. ELSEVIER SCIENCE SA. 1996: 76–83

  View details for Web of Science ID A1996UM53400014

• Microstructural dynamics of a homopolymer melt investigated using two-dimensional Raman scattering MACROMOLECULES Huang, K., Archer, L. A., Fuller, G. G. 1996; 29 (3): 966-972

  View details for Web of Science ID A1996TT68800023

• In situ optical studies of flow-induced orientation in a two-dimensional polymer solution MACROMOLECULES FRIEDENBERG, M. C., Fuller, G. G., Frank, C. W., Robertson, C. R. 1996; 29 (2): 705-712

  View details for Web of Science ID A1996TQ37900026

• Dynamic response of a near-critical polymer blend solution under oscillatory shear flow JOURNAL OF RHEOLOGY Lai, J., Fuller, G. G. 1996; 40 (1): 153-166

  View details for Web of Science ID A1996TQ17700009

• A RHEOOPTICAL STUDY OF NEAR-CRITICAL POLYMER-SOLUTIONS UNDER OSCILLATORY SHEAR-FLOW JOURNAL OF RHEOLOGY Lai, J., Fuller, G. G. 1995; 39 (5): 893-906

  View details for Web of Science ID A1995RU72800006

• THE STRESS JUMP OF A SEMIRIGID MACROMOLECULE AFTER SHEAR - COMPARISON OF THE ELASTIC STRESS TO THE BIREFRINGENCE JOURNAL OF RHEOLOGY Smyth, S. F., Liang, C. H., Mackay, M. E., Fuller, G. G. 1995; 39 (4): 659-672

  View details for Web of Science ID A1995RH27400001

• OPTICAL RHEOMETRY OF MULTICOMPONENT POLYMER LIQUIDS 35th IUPAC International Symposium on Macromolecules (MACROAKRON 94) Fuller, G. G. WILEY-V C H VERLAG GMBH. 1995: 997–1003

  View details for Web of Science ID A1995RZ12400068

• RHEOOPTICAL CHARACTERIZATION (FLOW-BIREFRINGENCE AND FLOW-DICHROISM) OF THE TOBACCO-MOSAIC-VIRUS MACROMOLECULAR CHEMISTRY AND PHYSICS REINHARDT, U. T., DEGROOT, E. L., Fuller, G. G., Kulicke, W. M. 1995; 196 (1): 63-74

  View details for Web of Science ID A1995QB40800003

• STRUCTURE AND DYNAMICS OF CONCENTRATION FLUCTUATIONS IN A POLYMER BLEND SOLUTION UNDER SHEAR-FLOW JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS Lai, A., Fuller, G. G. 1994; 32 (15): 2461-2474

  View details for Web of Science ID A1994PN08400003

• PATTERN AND SEGMENT RELAXATION IN A BLOCK-COPOLYMER MELT FOLLOWING STEP SHEAR-FLOW MACROMOLECULES Archer, L. A., Fuller, G. G. 1994; 27 (24): 7152-7156

  View details for Web of Science ID A1994PU64800024

• COMPONENT DYNAMICS IN MISCIBLE BLENDS OF 1,4-POLYISOPRENE AND 1,2-POLYBUTADIENE MACROMOLECULES ZAWADA, J. A., Fuller, G. G., Colby, R. H., Fetters, L. J., Roovers, J. 1994; 27 (23): 6861-6870

  View details for Web of Science ID A1994PQ78300026

• MEASURING COMPONENT CONTRIBUTIONS TO THE DYNAMIC MODULUS IN MISCIBLE POLYMER BLENDS MACROMOLECULES ZAWADA, J. A., Fuller, G. G., Colby, R. H., Fetters, L. J., Roovers, J. 1994; 27 (23): 6851-6860

  View details for Web of Science ID A1994PQ78300025

• MONOLAYERS OF PERFLUOROPOLYETHERS WITH A HYDROPHILIC HEAD GROUP LANGMUIR Goedel, W. A., Wu, H., FRIEDENBERG, M. C., Fuller, G. G., Foster, M., Frank, C. W. 1994; 10 (11): 4209-4218

  View details for Web of Science ID A1994PT25100049

• INVESTIGATING MISCIBLE POLYMER BLEND DYNAMICS WITH OPTICAL AND MECHANICAL RHEOMETRY 2nd International Discussion Meeting on Relaxations in Complex Systems Fuller, G. G., ZAWADA, J. A., Colby, R. H. ELSEVIER SCIENCE BV. 1994: 668–673

  View details for Web of Science ID A1994PK61000002

• OPTICAL AND MECHANICAL-PROPERTIES OF A STAR DIBLOCK COPOLYMER MELT IN OSCILLATORY SHEAR-FLOW MACROMOLECULES Archer, L. A., Fuller, G. G. 1994; 27 (17): 4804-4809

  View details for Web of Science ID A1994PC27600022

• SEGMENT ORIENTATION IN A QUIESCENT BLOCK-COPOLYMER MELT STUDIED BY RAMAN-SCATTERING MACROMOLECULES Archer, L. A., Fuller, G. G. 1994; 27 (15): 4359-4363

  View details for Web of Science ID A1994NY41800042

• STRUCTURE AND OPTICAL ANISOTROPIES OF CRITICAL POLYMER-SOLUTIONS IN ELECTRIC-FIELDS JOURNAL OF CHEMICAL PHYSICS Wirtz, D., WERNER, D. E., Fuller, G. G. 1994; 101 (2): 1679-1686

  View details for Web of Science ID A1994NW97900082

• ORIENTATION DYNAMICS OF A POLYMER MELT STUDIED BY POLARIZATION-MODULATED LASER RAMAN-SCATTERING JOURNAL OF RHEOLOGY Archer, L. A., Huang, K., Fuller, G. G. 1994; 38 (4): 1101-1125

  View details for Web of Science ID A1994NW09300019

• RELAXATION DYNAMICS OF BIDISPERSE TEMPORARY NETWORKS MACROMOLECULES Seidel, U., Stadler, R., Fuller, G. G. 1994; 27 (8): 2066-2072

  View details for Web of Science ID A1994NF81000014

• FORMATION OF BILAYER DISKS AND 2-DIMENSIONAL FOAMS ON A COLLAPSING EXPANDING LIQUID-CRYSTAL MONOLAYER LANGMUIR FRIEDENBERG, M. C., Fuller, G. G., Frank, C. W., Robertson, C. R. 1994; 10 (4): 1251-1256

  View details for Web of Science ID A1994NH59700046

• CONCENTRATION FLUCTUATION ENHANCEMENT IN POLYMER-SOLUTIONS BY EXTENSIONAL FLOW MACROMOLECULES VANEGMOND, J. W., Fuller, G. G. 1993; 26 (26): 7182-7188

  View details for Web of Science ID A1993MN47300011

• PHASE-TRANSITIONS INDUCED BY ELECTRIC-FIELDS IN NEAR-CRITICAL POLYMER-SOLUTIONS PHYSICAL REVIEW LETTERS Wirtz, D., Fuller, G. G. 1993; 71 (14): 2236-2239

  View details for Web of Science ID A1993MA02700018

• SCATTERING DICHROISM MEASUREMENTS OF FLOW-INDUCED STRUCTURE OF A SHEAR THICKENING SUSPENSION JOURNAL OF COLLOID AND INTERFACE SCIENCE DHAENE, P., Mewis, J., Fuller, G. G. 1993; 156 (2): 350-358

  View details for Web of Science ID A1993KT88300014

• INVESTIGATION OF XANTHAN GUM SOLUTION BEHAVIOR UNDER SHEAR-FLOW USING RHEOOPTICAL TECHNIQUES MACROMOLECULES Meyer, E. L., Fuller, G. G., Clark, R. C., Kulicke, W. M. 1993; 26 (3): 504-511

  View details for Web of Science ID A1993KK47000016

• ORIENTATION DYNAMICS OF SIDE-CHAIN POLYMERS SUBJECT TO ELECTRIC-FIELDS .1. STEADY-STATE ACTA POLYMERICA HOFFMANN, C. L., Man, H. T., Fuller, G. G. 1993; 44 (1): 39-49

  View details for Web of Science ID A1993KP35000006

• FLOW-INDUCED CONCENTRATION FLUCTUATIONS IN POLYMER-SOLUTIONS - STRUCTURE PROPERTY RELATIONSHIPS RHEOLOGICA ACTA Moldenaers, P., Yanase, H., Mewis, J., Fuller, G. G., Lee, C. S., Magda, J. J. 1993; 32 (1): 1-8

  View details for Web of Science ID A1993KR52200001

• ELECTRIC-FIELD INDUCED STRUCTURE IN DENSE SUSPENSIONS JOURNAL OF COLLOID AND INTERFACE SCIENCE Smith, K. L., Fuller, G. G. 1993; 155 (1): 183-190

  View details for Web of Science ID A1993KK64600024

• ELECTRIC-FIELD-INDUCED STRUCTURE IN POLYMER-SOLUTIONS NEAR THE CRITICAL-POINT MACROMOLECULES Wirtz, D., Berend, K., Fuller, G. G. 1992; 25 (26): 7234-7246

  View details for Web of Science ID A1992KE27700027

• COMPARISON OF NUMERICAL SIMULATIONS AND BIREFRINGENCE MEASUREMENTS IN VISCOELASTIC FLOW BETWEEN ECCENTRIC ROTATING CYLINDERS JOURNAL OF RHEOLOGY Rajagopalan, D., Byars, J. A., Armstrong, R. C., Brown, R. A., Lee, J. S., Fuller, G. G. 1992; 36 (7): 1349-1375

  View details for Web of Science ID A1992JT36400012

• COMPONENT RELAXATION DYNAMICS IN A MISCIBLE POLYMER BLEND - POLY(ETHYLENE OXIDE) POLY(METHYL METHACRYLATE) MACROMOLECULES ZAWADA, J. A., YLITALO, C. M., Fuller, G. G., Colby, R. H., Long, T. E. 1992; 25 (11): 2896-2902

  View details for Web of Science ID A1992HX03300017

• TIME-DEPENDENT SMALL-ANGLE LIGHT-SCATTERING OF SHEAR-INDUCED CONCENTRATION FLUCTUATIONS IN POLYMER-SOLUTIONS JOURNAL OF CHEMICAL PHYSICS VANEGMOND, J. W., WERNER, D. E., Fuller, G. G. 1992; 96 (10): 7742-7757

  View details for Web of Science ID A1992HU55700057

• DYNAMICS OF POLYMERIC LIQUIDS USING POLARIZATION-MODULATED LASER RAMAN-SCATTERING POLYMER Archer, L. A., Fuller, G. G., NUNNELLEY, L. 1992; 33 (17): 3574-3581

  View details for Web of Science ID A1992JL83600006

• OLIGOMERS AS MOLECULAR PROBES OF ORIENTATIONAL COUPLING INTERACTIONS IN POLYMER MELTS AND NETWORKS POLYMER YLITALO, C. M., ZAWADA, J. A., Fuller, G. G., Abetz, V., Stadler, R. 1992; 33 (14): 2949-2960

  View details for Web of Science ID A1992JF28200011

• LINEAR INFRARED DICHROISM BY A DOUBLE MODULATION TECHNIQUE 9TH EUROPEAN SYMP ON POLYMER SPECTROSCOPY ( ESOPS 91 ) Abetz, V., Fuller, G. G., Stadler, R. HUTHIG & WEPF VERLAG. 1991: 23–40

  View details for Web of Science ID A1991HC47000004

• 3RD NORMAL STRESS DIFFERENCE AND COMPONENT RELAXATION SPECTRA FOR BIDISPERSE METLS UNDER OSCILLATORY SHEAR MACROMOLECULES Kornfield, J. A., Fuller, G. G., Pearson, D. S. 1991; 24 (19): 5429-5441

  View details for Web of Science ID A1991GF73000034

• INFRARED POLARIMETRY STUDIES FOR MULTICOMPONENT POLYMER MELTS INTERNATIONAL DISCUSSION MEETING ON RELAXATIONS IN COMPLEX SYSTEMS Fuller, G. G., YLITALO, C. M. ELSEVIER SCIENCE BV. 1991: 676–684

  View details for Web of Science ID A1991FV57600023

• ROLE OF DIRECTOR TUMBLING IN THE RHEOLOGY OF POLYMER LIQUID-CRYSTAL SOLUTIONS MACROMOLECULES Burghardt, W. R., Fuller, G. G. 1991; 24 (9): 2546-2555

  View details for Web of Science ID A1991FJ88100063

• OPTICAL ANISOTROPY IN COLLOIDAL CRYSTALS JOURNAL OF CHEMICAL PHYSICS MONOVOUKAS, Y., Fuller, G. G., Gast, A. P. 1990; 93 (11): 8294-8299

  View details for Web of Science ID A1990EL29400084

• TRANSIENT SHEAR-FLOW OF NEMATIC LIQUID-CRYSTALS - MANIFESTATIONS OF DIRECTOR TUMBLING JOURNAL OF RHEOLOGY Burghardt, W. R., Fuller, G. G. 1990; 34 (6): 959-992

  View details for Web of Science ID A1990DR84600008

• INFRARED LINEAR DICHROISM SPECTROSCOPY BY A DOUBLE MODULATION TECHNIQUE POLYMER BULLETIN Abetz, V., Fuller, G. G., Stadler, R. 1990; 23 (4): 447-454

  View details for Web of Science ID A1990CW63700013

• 2-COLOR ROTARY MODULATED FLOW BIREFRINGENCE RHEOLOGICA ACTA Abetz, V., Fuller, G. G. 1990; 29 (1): 11-15

  View details for Web of Science ID A1990CW60200002

• THE OPTICAL AND MECHANICAL RESPONSE OF FLEXIBLE POLYMER-SOLUTIONS TO EXTENSIONAL FLOW JOURNAL OF NON-NEWTONIAN FLUID MECHANICS CATHEY, C. A., Fuller, G. G. 1990; 34 (1): 63-88

  View details for Web of Science ID A1990CM96500005

• OPTICAL RHEOMETRY ANNUAL REVIEW OF FLUID MECHANICS Fuller, G. G. 1990; 22: 387-417

  View details for Web of Science ID A1990CK57100014

• INFRARED DICHROISM MEASUREMENTS OF MOLECULAR RELAXATION IN BINARY BLEND MELT RHEOLOGY MACROMOLECULES Kornfield, J. A., Fuller, G. G., Pearson, D. S. 1989; 22 (3): 1334-1345

  View details for Web of Science ID A1989T785100055

• MECHANICAL AND OPTICAL RHEOMETRY OF POLYMER LIQUID-CRYSTAL DOMAIN-STRUCTURE MACROMOLECULES Moldenaers, P., Fuller, G., Mewis, J. 1989; 22 (2): 960-965

  View details for Web of Science ID A1989T340200071

• RHEOLOGICALLY INTERESTING POLYSACCHARIDES FROM YEASTS APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY Petersen, G. R., Nelson, G. A., CATHEY, C. A., Fuller, G. G. 1989; 20-1: 845-867

  View details for Web of Science ID A1989U642400063

• UNIAXIAL AND BIAXIAL EXTENSIONAL VISCOSITY MEASUREMENTS OF DILUTE AND SEMI-DILUTE SOLUTIONS OF RIGID ROD POLYMERS JOURNAL OF NON-NEWTONIAN FLUID MECHANICS CATHEY, C. A., Fuller, G. G. 1988; 30 (2-3): 303-316

  View details for Web of Science ID A1988R635000014

• THE OPTICAL ANISOTROPY OF SHEARED HEMATITE SUSPENSIONS JOURNAL OF COLLOID AND INTERFACE SCIENCE Johnson, S. J., Fuller, G. G. 1988; 124 (2): 441-451

  View details for Web of Science ID A1988P746300009

• THE DICHROISM AND BIREFRINGENCE OF A HARD-SPHERE SUSPENSION UNDER SHEAR JOURNAL OF CHEMICAL PHYSICS Wagner, N. J., Fuller, G. G., Russel, W. B. 1988; 89 (3): 1580-1587

  View details for Web of Science ID A1988P336300040

• OPTICAL MEASUREMENTS OF PARTICLE ORIENTATION IN MAGNETIC MEDIA JOURNAL OF APPLIED PHYSICS NUNNELLEY, L., Fuller, G. G. 1988; 63 (5): 1687-1690

  View details for Web of Science ID A1988P087900063

• THE SPATIAL DEVELOPMENT OF TRANSIENT COUETTE-FLOW AND SHEAR-WAVE PROPAGATION IN POLYMERIC LIQUIDS BY FLOW BIREFRINGENCE JOURNAL OF NON-NEWTONIAN FLUID MECHANICS Lee, J. S., Fuller, G. G. 1987; 26 (1): 57-76

  View details for Web of Science ID A1987L061200003

• CONSERVATIVE DICHROISM OF A SHEARED SUSPENSION IN THE RAYLEIGH-GANS LIGHT-SCATTERING APPROXIMATION JOURNAL OF COLLOID AND INTERFACE SCIENCE Frattini, P. L., Fuller, G. G. 1987; 119 (2): 335-351

  View details for Web of Science ID A1987K337300004

• EXTENSIONAL VISCOSITY MEASUREMENTS FOR LOW-VISCOSITY FLUIDS JOURNAL OF RHEOLOGY Fuller, G. G., CATHEY, C. A., Hubbard, B., ZEBROWSKI, B. E. 1987; 31 (3): 235-249

  View details for Web of Science ID A1987G904300002

• THE DYNAMICS OF COLLOIDAL PARTICLES SUSPENDED IN A 2ND-ORDER FLUID FARADAY DISCUSSIONS Johnson, S. J., Fuller, G. G. 1987; 83: 271-?

  View details for Web of Science ID A1987L579400020

• RHEOOPTICAL STUDIES OF THE EFFECT OF WEAK BROWNIAN ROTATIONS IN SHEARED SUSPENSIONS JOURNAL OF FLUID MECHANICS Frattini, P. L., Fuller, G. G. 1986; 168: 119-150

  View details for Web of Science ID A1986D634200005

• FLOWING COLLOIDAL SUSPENSIONS IN NON-NEWTONIAN SUSPENDING FLUIDS - DECOUPLING THE COMPOSITE BIREFRINGENCE RHEOLOGICA ACTA Johnson, S. J., Fuller, G. G. 1986; 25 (4): 405-417

  View details for Web of Science ID A1986E103500009

• SOME EXPERIMENTAL RESULTS ON THE DEVELOPMENT OF COUETTE-FLOW FOR NON-NEWTONIAN FLUIDS JOURNAL OF NON-NEWTONIAN FLUID MECHANICS Chow, A. W., Fuller, G. G. 1985; 17 (2): 233-243

  View details for Web of Science ID A1985AER6300007

• ADSORPTION AND DESORPTION OF FLEXIBLE POLYMER-CHAINS IN FLOWING SYSTEMS JOURNAL OF COLLOID AND INTERFACE SCIENCE Lee, J. J., Fuller, G. G. 1985; 103 (2): 569-577

  View details for Web of Science ID A1985ACK0500025

• ADSORBED POLYMER LAYERS SUBJECTED TO FLOW AIP CONFERENCE PROCEEDINGS Fuller, G. G., Lee, J. J. 1985: 263-269

  View details for Web of Science ID A1985A653900020

• DYNAMICS OF RIGID DUMBBELLS IN CONFINED GEOMETRIES .2. TIME-DEPENDENT SHEAR-FLOW JOURNAL OF NON-NEWTONIAN FLUID MECHANICS Park, O. O., Fuller, G. G. 1985; 18 (2): 111-122

  View details for Web of Science ID A1985AMT4700001

• SIMULTANEOUS DICHROISM AND BIREFRINGENCE MEASUREMENTS OF DILUTE COLLOIDAL SUSPENSIONS IN TRANSIENT SHEAR-FLOW JOURNAL OF COLLOID AND INTERFACE SCIENCE Johnson, S. J., Frattini, P. L., Fuller, G. G. 1985; 104 (2): 440-455

  View details for Web of Science ID A1985AFY2300013

• RHEO-OPTICAL STUDIES OF CONCENTRATED POLYSTYRENE SOLUTIONS SUBJECTED TO TRANSIENT SIMPLE SHEAR-FLOW JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS ZEBROWSKI, B. E., Fuller, G. G. 1985; 23 (3): 575-589

  View details for Web of Science ID A1985ADN6900013

• SMALL-ANGLE LIGHT-SCATTERING AS A PROBE OF FLOW-INDUCED PARTICLE ORIENTATION JOURNAL OF COLLOID AND INTERFACE SCIENCE SALEM, A. J., Fuller, G. G. 1985; 108 (1): 149-157

  View details for Web of Science ID A1985ATW2400016

• RHEOOPTICAL RESPONSE OF RODLIKE CHAINS SUBJECT TO TRANSIENT SHEAR-FLOW .1. MODEL-CALCULATIONS ON THE EFFECTS OF POLYDISPERSITY MACROMOLECULES Chow, A. W., Fuller, G. G. 1985; 18 (4): 786-793

  View details for Web of Science ID A1985AFT4500033

• THE EFFECT OF SEGMENT BOUNDARY HYDRODYNAMIC INTERACTIONS ON THE DYNAMICS OF ADSORBED POLYMER-CHAINS SUBJECTED TO FLOW JOURNAL OF COLLOID AND INTERFACE SCIENCE Lee, J. J., Fuller, G. G. 1985; 107 (2): 308-313

  View details for Web of Science ID A1985ASC0300003

• RHEOOPTICAL RESPONSE OF RODLIKE, SHORTENED COLLAGEN PROTEIN TO TRANSIENT SHEAR-FLOW MACROMOLECULES Chow, A. W., Fuller, G. G., Wallace, D. G., Madri, J. A. 1985; 18 (4): 805-810

  View details for Web of Science ID A1985AFT4500035

• RHEOOPTICAL RESPONSE OF RODLIKE CHAINS SUBJECT TO TRANSIENT SHEAR-FLOW .2. 2-COLOR FLOW BIREFRINGENCE MEASUREMENTS ON COLLAGEN PROTEIN MACROMOLECULES Chow, A. W., Fuller, G. G., Wallace, D. G., Madri, J. A. 1985; 18 (4): 793-804

  View details for Web of Science ID A1985AFT4500034

• ELLIPSOMETRY STUDIES OF ADSORBED POLYMER-CHAINS SUBJECTED TO FLOW MACROMOLECULES Lee, J. J., Fuller, G. G. 1984; 17 (3): 375-380

  View details for Web of Science ID A1984SJ52200021

• DYNAMICS OF RIGID AND FLEXIBLE POLYMER-CHAINS IN CONFINED GEOMETRIES .1. STEADY SIMPLE SHEAR-FLOW JOURNAL OF NON-NEWTONIAN FLUID MECHANICS Park, O. O., Fuller, G. G. 1984; 15 (3): 309-329

  View details for Web of Science ID A1984TM26700003

• THE DYNAMICS OF DILUTE COLLOIDAL SUSPENSIONS SUBJECT TO TIME-DEPENDENT FLOW-FIELDS BY CONSERVATIVE DICHROISM JOURNAL OF COLLOID AND INTERFACE SCIENCE Frattini, P. L., Fuller, G. G. 1984; 100 (2): 506-518

  View details for Web of Science ID A1984TC05400018

• FLOW-ENHANCED DESORPTION OF ADSORBED FLEXIBLE POLYMER-CHAINS ACS SYMPOSIUM SERIES Fuller, G. G., Lee, J. J. 1984; 240: 67-76

  View details for Web of Science ID A1984SC80800005

• RESPONSE OF MODERATELY CONCENTRATED XANTHAN GUM SOLUTIONS TO TIME-DEPENDENT FLOWS USING 2-COLOR FLOW BIREFRINGENCE JOURNAL OF RHEOLOGY Chow, A. W., Fuller, G. G. 1984; 28 (1): 23-43

  View details for Web of Science ID A1984SB85200002

• DYNAMICS OF ADSORBED POLYMER-CHAINS SUBJECTED TO FLOW - THE DUMBBELL MODEL JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS Fuller, G. G. 1983; 21 (1): 151-157

  View details for Web of Science ID A1983PW28400011