Ben Ou

All Publications

• Saponin nanoparticle adjuvants incorporating Toll-like receptor agonists drive distinct immune signatures and potent vaccine responses. Science advances Ou, B. S., Baillet, J., Filsinger Interrante, M. V., Adamska, J. Z., Zhou, X., Saouaf, O. M., Yan, J., Klich, J. H., Jons, C. K., Meany, E. L., Valdez, A. S., Carter, L., Pulendran, B., King, N. P., Appel, E. A. 2024; 10 (32): eadn7187

  Abstract

  Over the past few decades, the development of potent and safe immune-activating adjuvant technologies has become the heart of intensive research in the constant fight against highly mutative and immune evasive viruses such as influenza, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and human immunodeficiency virus (HIV). Herein, we developed a highly modular saponin-based nanoparticle platform incorporating Toll-like receptor agonists (TLRas) including TLR1/2a, TLR4a, and TLR7/8a adjuvants and their mixtures. These various TLRa-saponin nanoparticle adjuvant constructs induce unique acute cytokine and immune-signaling profiles, leading to specific T helper responses that could be of interest depending on the target disease for prevention. In a murine vaccine study, the adjuvants greatly improved the potency, durability, breadth, and neutralization of both COVID-19 and HIV vaccine candidates, suggesting the potential broad application of these adjuvant constructs to a range of different antigens. Overall, this work demonstrates a modular TLRa-SNP adjuvant platform that could improve the design of vaccines and affect modern vaccine development.

  View details for DOI 10.1126/sciadv.adn7187

  View details for PubMedID 39110802

  View details for PubMedCentralID PMC11305391

• Generation of an inflammatory niche in an injectable hydrogel depot through recruitment of key immune cells improves efficacy of mRNA vaccines. bioRxiv : the preprint server for biology Meany, E. L., Klich, J. H., Jons, C. K., Mao, T., Chaudhary, N., Utz, A., Baillet, J., Song, Y. E., Saouaf, O. M., Ou, B. S., Williams, S. C., Eckman, N., Irvine, D. J., Appel, E. 2024

  Abstract

  Messenger RNA (mRNA) delivered in lipid nanoparticles (LNPs) rose to the forefront of vaccine candidates during the COVID-19 pandemic due in part to scalability, adaptability, and potency. Yet there remain critical areas for improvements of these vaccines in durability and breadth of humoral responses. In this work, we explore a modular strategy to target mRNA/LNPs to antigen presenting cells with an injectable polymer-nanoparticle (PNP) hydrogel depot technology which recruits key immune cells and forms an immunological niche in vivo. We characterize this niche on a single cell level and find it is highly tunable through incorporation of adjuvants like MPLAs and 3M-052. Delivering commercially available SARS-CoV-2 mRNA vaccines in PNP hydrogels improves the durability and quality of germinal center reactions, and the magnitude, breadth, and durability of humoral responses. The tunable immune niche formed within PNP hydrogels effectively skews immune responses based on encapsulated adjuvants, creating opportunities to precisely modulate mRNA/LNP vaccines for various indications from infectious diseases to cancers.

  View details for DOI 10.1101/2024.07.05.602305

  View details for PubMedID 39026835

• Saponin Nanoparticle Adjuvants Incorporating Toll-Like Receptor Agonists Drive Distinct Immune Signatures and Potent Vaccine Responses. bioRxiv : the preprint server for biology Ou, B. S., Baillet, J., Filsinger Interrante, M. V., Adamska, J. Z., Zhou, X., Saouaf, O. M., Yan, J., Klich, J. H., Jons, C. K., Meany, E. L., Valdez, A. S., Carter, L., Pulendran, B., King, N. P., Appel, E. A. 2024

  Abstract

  Over the past few decades, the development of potent and safe immune-activating adjuvant technologies has become the heart of intensive research in the constant fight against highly mutative and immune evasive viruses such as influenza, SARS-CoV-2, and HIV. Herein, we developed a highly modular saponin-based nanoparticle platform incorporating toll-like receptor agonists (TLRas) including TLR1/2a, TLR4a, TLR7/8a adjuvants and their mixtures. These various TLRa-SNP adjuvant constructs induce unique acute cytokine and immune-signaling profiles, leading to specific Th-responses that could be of interest depending on the target disease for prevention. In a murine vaccine study, the adjuvants greatly improved the potency, durability, breadth, and neutralization of both COVID-19 and HIV vaccine candidates, suggesting the potential broad application of these adjuvant constructs to a range of different antigens. Overall, this work demonstrates a modular TLRa-SNP adjuvant platform which could improve the design of vaccines for and dramatically impact modern vaccine development.Teaser: Saponin-TLRa nanoadjuvants provide distinct immune signatures and drive potent, broad, durable COVID-19 and HIV vaccine responses.

  View details for DOI 10.1101/2023.07.16.549249

  View details for PubMedID 37577608

• Nanoparticle-Conjugated Toll-Like Receptor 9 Agonists Improve the Potency, Durability, and Breadth of COVID-19 Vaccines. ACS nano Ou, B. S., Baillet, J., Picece, V. C., Gale, E. C., Powell, A. E., Saouaf, O. M., Yan, J., Nejatfard, A., Lopez Hernandez, H., Appel, E. A. 2024

  Abstract

  Development of effective vaccines for infectious diseases has been one of the most successful global health interventions in history. Though, while ideal subunit vaccines strongly rely on antigen and adjuvant(s) selection, the mode and time scale of exposure to the immune system has often been overlooked. Unfortunately, poor control over the delivery of many adjuvants, which play a key role in enhancing the quality and potency of immune responses, can limit their efficacy and cause off-target toxicities. There is a critical need for improved adjuvant delivery technologies to enhance their efficacy and boost vaccine performance. Nanoparticles have been shown to be ideal carriers for improving antigen delivery due to their shape and size, which mimic viral structures but have been generally less explored for adjuvant delivery. Here, we describe the design of self-assembled poly(ethylene glycol)-b-poly(lactic acid) nanoparticles decorated with CpG, a potent TLR9 agonist, to increase adjuvanticity in COVID-19 vaccines. By controlling the surface density of CpG, we show that intermediate valency is a key factor for TLR9 activation of immune cells. When delivered with the SARS-CoV-2 spike protein, CpG nanoparticle (CpG-NP) adjuvant greatly improves the magnitude and duration of antibody responses when compared to soluble CpG, and results in overall greater breadth of immunity against variants of concern. Moreover, encapsulation of CpG-NP into injectable polymeric-nanoparticle (PNP) hydrogels enhances the spatiotemporal control over codelivery of CpG-NP adjuvant and spike protein antigen such that a single immunization of hydrogel-based vaccines generates humoral responses comparable to those of a typical prime-boost regimen of soluble vaccines. These delivery technologies can potentially reduce the costs and burden of clinical vaccination, both of which are key elements in fighting a pandemic.

  View details for DOI 10.1021/acsnano.3c09700

  View details for PubMedID 38215338

• A Regimen Compression Strategy for Commercial Vaccines Leveraging an Injectable Hydrogel Depot Technology for Sustained Vaccine Exposure ADVANCED THERAPEUTICS Yan, J., Ou, B. S., Saouaf, O. M., Meany, E. L., Eckman, N., Appel, E. A. 2023

  View details for DOI 10.1002/adtp.202300108

  View details for Web of Science ID 001004577500001

• Broad and Durable Humoral Responses Following Single Hydrogel Immunization of SARS-CoV-2 Subunit Vaccine. Advanced healthcare materials Ou, B. S., Saouaf, O. M., Yan, J., Bruun, T. U., Baillet, J., Zhou, X., King, N. P., Appel, E. A. 2023: e2301495

  Abstract

  Most vaccines require several immunizations to induce robust immunity, and indeed, most SARS-CoV-2 vaccines require an initial two-shot regimen followed by several boosters to maintain efficacy. Such a complex series of immunizations unfortunately increases the cost and complexity of populations-scale vaccination and reduces overall compliance and vaccination rate. In a rapidly evolving pandemic affected by the spread of immune-escaping variants, there is an urgent need to develop vaccines capable of providing robust and durable immunity. In this work, we developed a single immunization SARS-CoV-2 subunit vaccine that could rapidly generate potent, broad, and durable humoral immunity. We leveraged injectable polymer-nanoparticle (PNP) hydrogels as a depot technology for the sustained delivery of a nanoparticle COVID antigen displaying multiple copies of the SARS-CoV-2 receptor-binding-domain (RBD-NP), and potent adjuvants including CpG and 3M-052. Compared to a clinically relevant prime-boost regimen with soluble vaccines formulated with CpG/Alum or 3M-052/Alum adjuvants, PNP hydrogel vaccines more rapidly generated higher, broader, and more durable antibody responses. Additionally, these single-immunization hydrogel-based vaccines elicited potent and consistent neutralizing responses. Overall, we show that PNP hydrogels elicit improved anti-COVID immune responses with only a single administration, demonstrating their potential as critical technologies to enhance our overall pandemic readiness. This article is protected by copyright. All rights reserved.

  View details for DOI 10.1002/adhm.202301495

  View details for PubMedID 37278391

• A regimen compression strategy for commercial vaccines leveraging an injectable hydrogel depot technology for sustained vaccine exposure. bioRxiv : the preprint server for biology Yan, J., Ou, B. S., Saouaf, O. M., Meany, E. L., Eckman, N., Appel, E. A. 2023

  Abstract

  Equitable global access to vaccines requires we overcome challenges associated with complex immunization schedules and their associated economic burdens that hinder delivery in under resourced environments. The rabies vaccine, for example, requires multiple immunizations for effective protection and each dose is cost prohibitive, and therefore inaccessibility disproportionately impacts low- and middle-income countries. In this work we developed an injectable hydrogel depot technology for sustained delivery of commercial inactivated rabies virus vaccines. In a mouse model, we showed that a single immunization of a hydrogel-based rabies vaccine elicited comparable antibody titers to a standard prime-boost bolus regimen of a commercial rabies vaccine, despite these hydrogel vaccines comprising only half of the total dose delivered in the bolus control. Moreover, these hydrogel-based vaccines elicited similar antigen-specific T-cell responses and neutralizing antibody responses compared to the bolus vaccine. Notably, we demonstrated that while addition of a potent clinical TLR4 agonist adjuvant to the gels slightly improved binding antibody responses, inclusion of this adjuvant to the inactivated virion vaccine was detrimental to neutralizing responses. Taken together, these results suggest that these hydrogels can enable an effective regimen compression and dosesparing strategy for improving global access to vaccines.

  View details for DOI 10.1101/2023.03.23.534005

  View details for PubMedID 36993717

• Sustained delivery approaches to improving adaptive immune responses. Advanced drug delivery reviews Ou, B. S., Saouaf, O. M., Baillet, J., Appel, E. A. 2022: 114401

  Abstract

  The immune system is one of the most important, complex biological networks regulating and protecting human health. Its precise modulation can prevent deadly infections and fight cancer. Accordingly, prophylactic vaccines and cancer immunotherapies are some of the most powerful technologies to protect against potential dangers through training of the immune system. Upon immunization, activation and maturation of B and T cells of the adaptive immune system are necessary for development of proper humoral and cellular protection. Yet, the exquisite organization of the immune system requires spatiotemporal control over the exposure of immunomodulatory signals. For example, while the human immune system has evolved to develop immunity to natural pathogenic infections that often last for weeks, current prophylactic vaccination technologies only expose the immune system to immunomodulatory signals for hours to days. It has become clear that leveraging sustained release technologies to prolong immunogen and adjuvant exposure can increase the potency, durability, and quality of adaptive immune responses. Over the past several years, tremendous breakthroughs have been made in the design of novel biomaterials such as nanoparticles, microparticles, hydrogels, and microneedles that can precisely control and the presentation of immunomodulatory signals to the immune system. In this review, we discuss relevant sustained release strategies and their corresponding benefits to cellular and humoral responses.

  View details for DOI 10.1016/j.addr.2022.114401

  View details for PubMedID 35750115

• Delivery of CAR-T cells in a transient injectable stimulatory hydrogel niche improves treatment of solid tumors. Science advances Grosskopf, A. K., Labanieh, L., Klysz, D. D., Roth, G. A., Xu, P., Adebowale, O., Gale, E. C., Jons, C. K., Klich, J. H., Yan, J., Maikawa, C. L., Correa, S., Ou, B. S., d'Aquino, A. I., Cochran, J. R., Chaudhuri, O., Mackall, C. L., Appel, E. A. 2022; 8 (14): eabn8264

  Abstract

  Adoptive cell therapy (ACT) has proven to be highly effective in treating blood cancers, but traditional approaches to ACT are poorly effective in treating solid tumors observed clinically. Novel delivery methods for therapeutic cells have shown promise for treatment of solid tumors when compared with standard intravenous administration methods, but the few reported approaches leverage biomaterials that are complex to manufacture and have primarily demonstrated applicability following tumor resection or in immune-privileged tissues. Here, we engineer simple-to-implement injectable hydrogels for the controlled co-delivery of CAR-T cells and stimulatory cytokines that improve treatment of solid tumors. The unique architecture of this material simultaneously inhibits passive diffusion of entrapped cytokines and permits active motility of entrapped cells to enable long-term retention, viability, and activation of CAR-T cells. The generation of a transient inflammatory niche following administration affords sustained exposure of CAR-T cells, induces a tumor-reactive CAR-T phenotype, and improves efficacy of treatment.

  View details for DOI 10.1126/sciadv.abn8264

  View details for PubMedID 35394838

• Hydrogel-Based Slow Release of a Receptor-Binding Domain Subunit Vaccine Elicits Neutralizing Antibody Responses Against SARS-CoV-2. Advanced materials (Deerfield Beach, Fla.) Gale, E. C., Powell, A. E., Roth, G. A., Meany, E. L., Yan, J., Ou, B. S., Grosskopf, A. K., Adamska, J., Picece, V. C., d'Aquino, A. I., Pulendran, B., Kim, P. S., Appel, E. A. 2021: e2104362

  Abstract

  The development of effective vaccines that can be rapidly manufactured and distributed worldwide is necessary to mitigate the devastating health and economic impacts of pandemics like COVID-19. The receptor-binding domain (RBD) of the SARS-CoV-2 spike protein, which mediates host cell entry of the virus, is an appealing antigen for subunit vaccines because it is efficient to manufacture, highly stable, and a target for neutralizing antibodies. Unfortunately, RBD is poorly immunogenic. While most subunit vaccines are commonly formulated with adjuvants to enhance their immunogenicity, clinically-relevant adjuvants Alum, AddaVax, and CpG/Alum are found unable to elicit neutralizing responses following a prime-boost immunization. Here, it has been shown that sustained delivery of an RBD subunit vaccine comprisingCpG/Alumadjuvant in an injectable polymer-nanoparticle (PNP) hydrogelelicited potentanti-RBD andanti-spikeantibody titers, providing broader protection against SARS-CoV-2 variants of concern compared to bolus administration of the same vaccine and vaccines comprising other clinically-relevant adjuvant systems. Notably, a SARS-CoV-2 spike-pseudotyped lentivirus neutralization assay revealed that hydrogel-based vaccines elicited potent neutralizing responses when bolus vaccines didnot. Together, these results suggest that slow delivery of RBD subunit vaccines with PNP hydrogels can significantly enhance the immunogenicity of RBD and induce neutralizing humoral immunity.

  View details for DOI 10.1002/adma.202104362

  View details for PubMedID 34651342

• Designing spatial and temporal control of vaccine responses. Nature reviews. Materials Roth, G. A., Picece, V. C., Ou, B. S., Luo, W., Pulendran, B., Appel, E. A. 2021: 1-22

  Abstract

  Vaccines are the key technology to combat existing and emerging infectious diseases. However, increasing the potency, quality and durability of the vaccine response remains a challenge. As our knowledge of the immune system deepens, it becomes clear that vaccine components must be in the right place at the right time to orchestrate a potent and durable response. Material platforms, such as nanoparticles, hydrogels and microneedles, can be engineered to spatially and temporally control the interactions of vaccine components with immune cells. Materials-based vaccination strategies can augment the immune response by improving innate immune cell activation, creating local inflammatory niches, targeting lymph node delivery and controlling the time frame of vaccine delivery, with the goal of inducing enhanced memory immunity to protect against future infections. In this Review, we highlight the biological mechanisms underlying strong humoral and cell-mediated immune responses and explore materials design strategies to manipulate and control these mechanisms.

  View details for DOI 10.1038/s41578-021-00372-2

  View details for PubMedID 34603749

• 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

• Modulation of injectable hydrogel properties for slow co-delivery of influenza subunit vaccine components enhance the potency of humoral immunity. Journal of biomedical materials research. Part A Saouaf, O. M., Roth, G. A., Ou, B. S., Smith, A. A., Yu, A. C., Gale, E. C., Grosskopf, A. K., Picece, V. C., Appel, E. A. 2021

  Abstract

  Vaccines are critical for combating infectious diseases across the globe. Influenza, for example, kills roughly 500,000 people annually worldwide, despite annual vaccination campaigns. Efficacious vaccines must elicit a robust and durable antibody response, and poor efficacy often arises from inappropriate temporal control over antigen and adjuvant presentation to the immune system. In this work, we sought to exploit the immune system's natural response to extended pathogen exposure during infection by designing an easily administered slow-delivery influenza vaccine platform. We utilized an injectable and self-healing polymer-nanoparticle (PNP) hydrogel platform to prolong the co-delivery of vaccine components to the immune system. We demonstrated that these hydrogels exhibit unique dynamic physical characteristics whereby physicochemically distinct influenza hemagglutinin antigen and a toll-like receptor 7/8 agonist adjuvant could be co-delivered over prolonged timeframes that were tunable through simple alteration of the gel formulation. We show a relationship between hydrogel physical properties and the resulting immune response to immunization. When administered in mice, hydrogel-based vaccines demonstrated enhancements in the magnitude and duration of humoral immune responses compared to alum, a widely used clinical adjuvant system. We found stiffer hydrogel formulations exhibited slower release and resulted in the greatest improvements to the antibody response while also enabling significant adjuvant dose sparing. In summary, this work introduces a simple and effective vaccine delivery platform that increases the potency and durability of influenza subunit vaccines.

  View details for DOI 10.1002/jbm.a.37203

  View details for PubMedID 33955657

• Enhanced Humoral Immune Response by High Density TLR Agonist Presentation on Hyperbranched Polymers ADVANCED THERAPEUTICS Liong, C. S., Smith, A. A., Mann, J. L., Roth, G. A., Gale, E. C., Maikawa, C. L., Ou, B. S., Appel, E. A. 2021

  View details for DOI 10.1002/adtp.202000081

  View details for Web of Science ID 000620203300001

• Selective Capture and Recovery of Monoclonal Antibodies by Self-Assembling Supramolecular Polymers of High Affinity for Protein Binding NANO LETTERS Li, Y., Lock, L., Mills, J., Ou, B. S., Morrow, M., Stern, D., Wang, H., Anderson, C. F., Xu, X., Ghose, S., Li, Z., Cui, H. 2020; 20 (10): 6957–65

  Abstract

  The separation and purification of therapeutic proteins from their biological resources pose a great limitation for industrial manufacturing of biologics in an efficient and cost-effective manner. We report here a supramolecular polymeric system that can undergo multiple reversible processes for efficient capture, precipitation, and recovery of monoclonal antibodies (mAbs). These supramolecular polymers, namely immunofibers (IFs), are formed by coassembly of a mAb-binding peptide amphiphile with a rationally designed filler molecule of varying stoichiometric ratios. Under the optimized conditions, IFs can specifically capture mAbs with a precipitation yield greater than 99%, leading to an overall mAb recovery yield of 94%. We also demonstrated the feasibility of capturing and recovering two mAbs from clarified cell culture harvest. These results showcase the promising potential of peptide-based supramolecular polymers as reversible affinity precipitants for mAb purification.

  View details for DOI 10.1021/acs.nanolett.0c01297

  View details for Web of Science ID 000598727300004

  View details for PubMedID 32852220

• Emerging biomaterials for downstream manufacturing of therapeutic proteins ACTA BIOMATERIALIA Li, Y., Stern, D., Lock, L., Mills, J., Ou, S., Morrow, M., Xu, X., Ghose, S., Li, Z., Cui, H. 2019; 95: 73–90

  Abstract

  Downstream processing is considered one of the most challenging phases of industrial manufacturing of therapeutic proteins, accounting for a large portion of the total production costs. The growing demand for therapeutic proteins in the biopharmaceutical market in addition to a significant rise in upstream titers have placed an increasing burden on the downstream purification process, which is often limited by high cost and insufficient capacities. To achieve efficient production and reduced costs, a variety of biomaterials have been exploited to improve the current techniques and also to develop superior alternatives. In this work, we discuss the significance of utilizing traditional biomaterials in downstream processing and review the recent progress in the development of new biomaterials for use in protein separation and purification. Several representative methods will be highlighted and discussed in detail, including affinity chromatography, non-affinity chromatography, membrane separations, magnetic separations, and precipitation/phase separations. STATEMENT OF SIGNIFICANCE: Nowadays, downstream processing of therapeutic proteins is facing great challenges created by the rapid increase of the market size and upstream titers, starving for significant improvements or innovations in current downstream unit operations. Biomaterials have been widely used in downstream manufacturing of proteins and efforts have been continuously devoted to developing more advanced biomaterials for the implementation of more efficient and economical purification methods. This review covers recent advances in the development and application of biomaterials specifically exploited for various chromatographic and non-chromatographic techniques, highlighting several promising alternative strategies.

  View details for DOI 10.1016/j.actbio.2019.03.015

  View details for Web of Science ID 000484878900006

  View details for PubMedID 30862553

• Co-assembled protein a mimicking peptide immunofibers for affinity precipitation of monoclonal antibodies Li, Y., Lock, L., Mills, J., Ou, S., Stern, D., Morrow, M., Xu, X., Ghose, S., Cui, H. AMER CHEMICAL SOC. 2019

  View details for Web of Science ID 000478861203494

• Bioinspired supramolecular engineering of self-assembling immunofibers for high affinity binding of immunoglobulin G BIOMATERIALS Li, Y., Lock, L., Wang, Y., Ou, S., Stern, D., Schon, A., Freire, E., Xu, X., Ghose, S., Li, Z., Cui, H. 2018; 178: 448–57

  Abstract

  Many one-dimensional (1D) nanostructures are constructed by self-assembly of peptides or peptide conjugates containing a short β-sheet sequence as the core building motif essential for the intermolecular hydrogen bonding that promotes directional, anisotropic growth of the resultant assemblies. While this molecular engineering strategy has led to the successful production of a plethora of bioactive filamentous β-sheet assemblies for interfacing with biomolecules and cells, concerns associated with effective presentation of α-helical epitopes and their function preservation have yet to be resolved. In this context, we report on the direct conjugation of the protein A mimicking peptide Z33, a motif containing two α-helices, to linear hydrocarbons to create self-assembling immuno-amphiphiles (IAs). Our results suggest that the resulting amphiphilic peptides can, despite lacking the essential β-sheet segment, effectively associate under physiological conditions into supramolecular immunofibers (IFs) while preserving their native α-helical conformation. Isothermal titration calorimetry (ITC) measurements confirmed that these self-assembling immunofibers can bind to the human immunoglobulin G class 1 (IgG1) with high specificity at pH 7.4, but with significantly weakened binding at pH 2.8. We further demonstrated the accessibility of Z33 ligand in the immunofibers using transmission electron microscopy (TEM) and confocal imaging. We believe these results shed important light into the supramolecular engineering of α-helical peptides into filamentous assemblies that may possess an important potential for antibody isolation.

  View details for DOI 10.1016/j.biomaterials.2018.04.032

  View details for Web of Science ID 000440959000032

  View details for PubMedID 29706234

• Diagnosis of immunomarkers in vivo via multiplexed surface enhanced Raman spectroscopy with gold nanostars NANOSCALE Ou, Y., Webb, J. A., O'Brien, C. M., Pence, I. J., Lin, E. C., Paul, E. P., Cole, D., Ou, S., Lapierre-Landry, M., DeLapp, R. C., Lippmann, E. S., Mahadevan-Jansen, A., Bardhan, R. 2018; 10 (27): 13092-13105

  Abstract

  In this work, we demonstrate the targeted diagnosis of immunomarker programmed death ligand 1 (PD-L1) and simultaneous detection of epidermal growth factor receptor (EGFR) in breast cancer tumors in vivo using gold nanostars (AuNS) with multiplexed surface enhanced Raman spectroscopy (SERS). Real-time longitudinal tracking with SERS demonstrated maximum accumulation of AuNS occurred 6 h post intravenous (IV) delivery, enabling detection of both biomarkers simultaneously. Raman signal correlating to both PD-L1 and EGFR decreased by ∼30% in control tumors where receptors were pre-blocked prior to AuNS delivery, indicating both the sensitivity and specificity of SERS in distinguishing tumors with different levels of PD-L1 and EGFR expression. Our in vivo study was combined with the first demonstration of ex vivo SERS spatial maps of whole tumor lesions that provided both a qualitative and quantitative assessment of biomarker status with near cellular-level resolution. High resolution SERS maps also provided an overview of AuNS distribution in tumors which correlated well with the vascular density. Mass spectrometry showed AuNS accumulation in tumor and liver, and clearance via spleen, and electron microscopy revealed AuNS were endocytosed in tumors, Kupffer cells in the liver, and macrophages in the spleen. This study demonstrates that SERS-based diagnosis mediated by AuNS provides an accurate measure of multiple biomarkers both in vivo and ex vivo, which will ultimately enable a clinically-translatable platform for patient-tailored immunotherapies and combination treatments.

  View details for DOI 10.1039/c8nr01478g

  View details for Web of Science ID 000438665100020

  View details for PubMedID 29961778

• Conformation Preservation of alpha-Helical Peptides within Supramolecular Filamentous Assemblies BIOMACROMOLECULES Li, Y., Wang, Y., Ou, S., Lock, L., Xu, X., Ghose, S., Li, Z., Cui, H. 2017; 18 (11): 3611–20

  Abstract

  Hydrogen-bonded β-sheets are the most commonly explored building motifs for creating peptide-based filamentous nanostructures; however, most bioactive epitopes must assume an α-helix conformation to exert their functions. Incorporating α-helical sequences into β-sheet-forming peptides often involves the use of a flexible spacer to alleviate the steric impact of the intermolecular hydrogen bonding on the α-helical conformation. In this context, we report our findings on the alkylation-regulated conformation preservation of α-helical peptides within their filamentous assemblies. We found that the chemical conjugation of two short linear hydrocarbons (octanoic acids, C8) can retain the α-helical conformation of two protein A-derived peptide sequences while effectively driving their assembly into filamentous nanostructures. In contrast, the use of a single palmitoyl tail (C16) of similar hydrophobicity would lead to formation of β-sheet assemblies. Our studies further demonstrated that the length of the conjugated hydrocarbon also plays an important role in partially preserving the native α-helical conformation, with longer ones promoting β-sheet formation and short ones stabilizing α-helices to some extent. We believe that these findings offer important guiding principles for the alkylation of self-assembling peptides containing α-helical sequences.

  View details for DOI 10.1021/acs.biomac.7b00992

  View details for Web of Science ID 000415391900018

  View details for PubMedID 28891286