Rainer Fasching

All Publications

• Nickel Silicide Nanowire Arrays for Anti-Reflective Electrodes in Photovoltaics ADVANCED FUNCTIONAL MATERIALS Dasgupta, N. P., Xu, S., Jung, H. J., Iancu, A., Fasching, R., Sinclair, R., Prinz, F. B. 2012; 22 (17): 3650-3657

  View details for DOI 10.1002/adfm.201200398

  View details for Web of Science ID 000308329800015

• Three-dimensional biodegradable microscaffolding: Scaffold characterization and cell population at single cell resolution ACTA BIOMATERIALIA Ryu, W., Hammerick, K. E., Kim, Y. B., Kim, J. B., Fasching, R., Prinz, F. B. 2011; 7 (9): 3325-3335

  Abstract

  Engineering artificial tissue scaffolds with a similar organization to that of the natural tissue is a key element to the successful recapitulation of function. However, three-dimensional (3-D) fabrication of tissue scaffolds containing complex microarchitectures still remains a challenge. In addition, little attention has been paid to the issue of how to incorporate cells within 3-D tissue scaffolds that contain precisely engineered architectures. Here we report a 3-D biodegradable microscaffolding (3D-BMS) technology and its process characterization as well as a microscale cellular loading technology as an efficient way to massively populate biodegradable polymers with cells at single cell resolution. In this study a particular emphasis was given to characterization of the material properties of the biodegradable polymers undergoing the 3D-BMS processes. Optimal process conditions were identified in order to avoid any unwanted change in material properties, such as crystallinity and scaffold strength, that have a direct impact on the degradation speed and physical integrity of the constructed scaffolds. For precise control of the cell distribution within the microstructured scaffolds a high precision microsieve structure was designed to localize rat hepatocytes and human articular chondrocytes in the biodegradable polymers. Cell suspensions were passed at a predetermined flow rate through biodegradable polymer layers that contained tapered microholes in a massively parallel process. This high resolution cell seeding method allows accurate manipulation of cell placement in thin layers of biodegradable polymers.

  View details for DOI 10.1016/j.actbio.2011.05.011

  View details for Web of Science ID 000294040900009

  View details for PubMedID 21640854

• In vivo O-2 measurement inside single photosynthetic cells BIOTECHNOLOGY LETTERS Bai, S., Ryu, W., Fasching, R. J., Grossman, A. R., Prinz, F. B. 2011; 33 (8): 1675-1681

  Abstract

  The oxygen evolution of single cells was investigated using a nano-probe with an ultra-micro electrode (UME) in a submicron sized system in combination with a micro-fluidic system. A single cell was immobilized in the micro-fluidic system and a nano-probe was inserted into the cytosolic space of the single cell. Then, the UME was used for an in vivo amperometric experiment at a fixed potential and electrochemical impedance spectroscopy to detect oxygen evolution of the single cell under various light intensities.

  View details for DOI 10.1007/s10529-011-0604-x

  View details for Web of Science ID 000293752000025

  View details for PubMedID 21476096

• Direct Extraction of Photosynthetic Electrons from Single Algal Cells by Nanoprobing System NANO LETTERS Ryu, W., Bai, S., Park, J. S., Huang, Z., Moseley, J., Fabian, T., Fasching, R. J., Grossman, A. R., Prinz, F. B. 2010; 10 (4): 1137-1143

  Abstract

  There are numerous sources of bioenergy that are generated by photosynthetic processes, for example, lipids, alcohols, hydrogen, and polysaccharides. However, generally only a small fraction of solar energy absorbed by photosynthetic organisms is converted to a form of energy that can be readily exploited. To more efficiently use the solar energy harvested by photosynthetic organisms, we evaluated the feasibility of generating bioelectricity by directly extracting electrons from the photosynthetic electron transport chain before they are used to fix CO(2) into sugars and polysaccharides. From a living algal cell, Chlamydomonas reinhardtii, photosynthetic electrons (1.2 pA at 6000 mA/m(2)) were directly extracted without a mediator electron carrier by inserting a nanoelectrode into the algal chloroplast and applying an overvoltage. This result may represent an initial step in generating "high efficiency" bioelectricity by directly harvesting high energy photosynthetic electrons.

  View details for DOI 10.1021/nl903141j

  View details for Web of Science ID 000276557100007

  View details for PubMedID 20201533

• Open micro-fluidic system for atomic force microscopy-guided in situ electrochemical probing of a single cell LAB ON A CHIP Ryu, W., Huang, Z., Park, J. S., Moseley, J., Grossman, A. R., Fasching, R. J., Prinz, F. B. 2008; 8 (9): 1460-1467

  Abstract

  Ultra-sharp nano-probes and customized atomic force microscopy (AFM) have previously been developed in our laboratory for in situ sub-cellular probing of electrochemical phenomena in living plant cells during their photosynthesis. However, this AFM-based electrochemical probing still has numerous engineering challenges such as immobilization of the live cells, compatibility of the immobilization procedure with AFM manipulation of the probe, maintenance of biological activity of the cells for an extended time while performing the measurements, and minimization of electrochemical noise. Thus, we have developed an open micro-fluidic channel system (OMFC) in which individual cells can be immobilized in micro-traps by capillary flow. This system affords easy AFM access and allows for maintenance of the cells in a well-defined chemical environment, which sustains their biological activity. The use of micro-channels for making the electrochemical measurements significantly reduces parasitic electrical capacitances and allows for current detection in the sub-pico-ampere range at high signal bandwidths. The OMFC was further studied using simulation packages for optimal design conditions. This system was successfully used to measure light-dependent oxidation currents of a few pico-amperes from the green alga Chlamydomonas reinhardtii.

  View details for DOI 10.1039/b803450h

  View details for Web of Science ID 000259676000007

  View details for PubMedID 18818800

• Solid oxide fuel cell with corrugated thin film electrolyte NANO LETTERS Su, P., Chao, C., Shim, J. H., Fasching, R., Prinz, F. B. 2008; 8 (8): 2289-2292

  Abstract

  A low temperature micro solid oxide fuel cell with corrugated electrolyte membrane was developed and tested. To increase the electrochemically active surface area, yttria-stabilized zirconia membranes with thickness of 70 nm were deposited onto prepatterned silicon substrates. Fuel cell performance of the corrugated electrolyte membranes released from silicon substrate showed an increase of power density relative to membranes with planar electrolytes. Maximum power densities of the corrugated fuel cells of 677 mW/cm2 and 861 mW/cm2 were obtained at 400 and 450 degrees C, respectively.

  View details for DOI 10.1021/nl800977z

  View details for Web of Science ID 000258440700030

  View details for PubMedID 18605702

• Controlled release of growth factors on allograft bone in vitro 5th Musculoskeletal Transplant Foundation Symposium Huang, Z., Ryu, W., Ren, P., Fasching, R., Goodman, S. B. SPRINGER. 2008: 1905–11

  Abstract

  Allografts are important alternatives to autografts for treating defects after major bone loss. Bone growth factors have both local autocrine and paracrine effects and regulate the growth, proliferation, and differentiation of osteoprogenitor cells. To study the effects of prolonged, continuous, local delivery of growth factors on bone growth, we developed a new microelectromechanical system (MEMS) drug delivery device. Bone marrow cells from mice were seeded on mouse allograft discs and cultured in osteogenic media with osteogenic protein 1 (OP-1) and/or basic fibroblast growth factor (FGF-2) delivered from MEMS devices for 6 weeks. We monitored bone formation by changes of bone volume using micro-CT scanning and release of osteocalcin using ELISA. The data suggest the MEMS devices delivered constant concentrations of OP-1 and FGF-2 to the media. Bone marrow cells grew on the allografts and increased bone volume. Addition of OP-1 increased bone formation whereas FGF-2 decreased bone formation. Local delivery of growth factors over a prolonged period modulated the differentiation of osteoprogenitor cells on allograft bone.

  View details for DOI 10.1007/s11999-008-0290-8

  View details for PubMedID 18509711

• Nanoscale probe system for cell-organelle analysis SENSORS AND ACTUATORS B-CHEMICAL Bai, S., Fabian, T., Prinz, F. B., Fasching, R. J. 2008; 130 (1): 249-257

  View details for DOI 10.1016/j.snb.2007.07.143

  View details for Web of Science ID 000254681900037

• Reversible oxidation of spinach ferredoxin at surface-modified electrodes JOURNAL OF THE ELECTROCHEMICAL SOCIETY Komadina, J., Walch, S., Fasching, R., Grossman, A., Prinz, F. B. 2008; 155 (10): B1008-B1012

  View details for DOI 10.1149/1.2962768

  View details for Web of Science ID 000258976500020

• Biodegradable micro-osmotic pump for long-term and controlled release of basic fibroblast growth factor JOURNAL OF CONTROLLED RELEASE Ryu, W., Huang, Z., Prinz, F. B., Goodman, S. B., Fasching, R. 2007; 124 (1-2): 98-105

  Abstract

  Microelectromechanical system (MEMS) technology not only provides the possibility of integration of multiple functions but also enables more precise control of dosing of therapeutic agents when the therapeutic window is very limited. Local delivery of basic fibroblast growth factor (bFGF) over a specific dose and time course is critical for mesenchymal tissue regeneration. However, bFGF is degraded quickly in vivo and difficulty of controlling the dose level impedes its effective use in angiogenesis and tissue regeneration. We constructed biodegradable micro-osmotic pumps based on MEMS technology for long-term controlled release of bFGF. The devices were constructed by micro-molding and thermal assembly of 85/15 poly(L-lactide-co-glycolide) sheets. The release of bFGF was regulated at 40 ng/day for four weeks; bioactivity was assessed by monitoring the growth of 3T3 fibroblasts. The proposed devices can be further miniaturized and used for the delivery of multiple therapeutic agents at the individual releasing schedules.

  View details for DOI 10.1016/j.jconrel.2007.08.024

  View details for PubMedID 17904240

• Fabrication of multi-layered biodegradable drug delivery device based on micro-structuring of PLGA polymers BIOMEDICAL MICRODEVICES Ryu, W. H., Vyakarnam, M., Greco, R. S., Prinz, F. B., Fasching, R. J. 2007; 9 (6): 845-853

  Abstract

  A programmable and biodegradable drug delivery device is desirable when a drug needs to be administered locally. While most local drug delivery devices made of biodegradable polymers relied on the degradation of the polymers, the degradation-based release control is often limited by the property of the polymers. Thus, we propose micro-geometry as an alternative measure of controlling drug release. The proposed devices consist of three functional layers: diffusion control layer via micro-orifices, diffusion layer, and drug reservoir layers. A micro-fabrication technology was used to shape an array of micro-orifices and micro-cavities in 85/15PLGA layers. A thin layer of fast degrading 50/50PLGA was placed as the diffusion layer between the 85/15PLGA layers to prevent any burst-type release. To modulate the release of the devices, the dimension and location of the micro-orifices were varied and the responding in vitro release response of tetracycline was monitored over 2 weeks. The release response to the different micro-geometry was prominent and further analyzed by FEM simulation. Comparison of the experiments to the simulated results identified that the variation of micro-geometry influenced also the volume-dependent degradation rate and induced the osmotic pressure.

  View details for DOI 10.1007/s10544-007-9097-8

  View details for Web of Science ID 000250462200009

  View details for PubMedID 17577671

• The construction of three-dimensional micro-fluidic scaffolds of biodegradable polymers by solvent vapor based bonding of micro-molded layers BIOMATERIALS Ryu, W., Min, S. W., Hammerick, K. E., Vyakarnam, M., Greco, R. S., Prinz, F. B., Fasching, R. J. 2007; 28 (6): 1174-1184

  Abstract

  It is increasingly important to control cell growth into and within artificial scaffolds. Tissues such as skin, blood vessels, and cartilage have multi-layer structures with different cells in each layer. With the aid of micro-fabrication technology, a novel scaffolding method for biodegradable polymers such as polylactic acid (PLA), polyglycolic acid (PGA), and the copolymers poly(lactide-co-glycolide)(PLGA), was developed to construct three-dimensional multi-layer micro-fluidic tissue scaffolds. The method emphasizes micro-fluidic interconnections between layers within the scaffolds and maintenance of high-resolution geometries during the bonding process for the creation of multi-layered scaffolds. Micro-holes (10-100 microm), micro-channels, and micro-cavities were all created by micro-molding. Solvent-vapor based bonding of micro-molded layers preserved 20 microm sized structures. Sample scaffolds were constructed for purposes such as channel-directed cell growth and size-based cell sorting. Further extension of these techniques to create a micro-vascular network within or between layers is possible. Culturing of human coronary artery endothelial cells (HCAECs) on the sample scaffolds demonstrated the biocompatibility of the developed process and the strong influence of high-resolution micro-geometries on HCAEC growth.

  View details for DOI 10.1016/j.biomaterials.2006.11.002

  View details for Web of Science ID 000243219000028

  View details for PubMedID 17126395

• High-performance ultrathin solid oxide fuel cells for low-temperature operation JOURNAL OF THE ELECTROCHEMICAL SOCIETY Huang, H., Nakamura, M., Su, P., Fasching, R., Saito, Y., Prinz, F. B. 2007; 154 (1): B20-B24

  View details for DOI 10.1149/1.2372592

  View details for Web of Science ID 000242538600013

• AFM/EC nano probing of single cells and organelles 6th IEEE Sensors Conference Fasching, R., Ryu, W., Bai, S., Park, J., Fabian, T., Moseley, J., Grossman, A., Prinz, F. IEEE. 2007: 699–702

  View details for Web of Science ID 000254563600177

• Microfabrication technology of biodegradable polymers for interconnecting microstructures JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Ryu, W., Fasching, R. J., Vyakarnam, M., Greco, R. S., Prinz, F. B. 2006; 15 (6): 1457-1465

  View details for DOI 10.1109/JMEMS.2006.883566

  View details for Web of Science ID 000242983300005

• Nanoscale electrochemical probes for single cell analysis 31st International Conference on Micro- and Nano-Engineering Fasching, R. J., Bai, S., Fabian, T., Prinz, F. B. ELSEVIER SCIENCE BV. 2006: 1638–41

  View details for DOI 10.1016/j.mee.2006.01.262

  View details for Web of Science ID 000237581900246

• Nanofabrication of electrochemical planar probes for single cell analysis Conference on Micromachining and Microfabrication Process Technology XI Fasching, R. J., Bai, S., Fabian, T., Prinz, F. B. SPIE-INT SOC OPTICAL ENGINEERING. 2006

  View details for DOI 10.1117/12.648950

  View details for Web of Science ID 000237146500002

• Cantilever tip probe arrays for simultaneous SECM and AFM analysis 10th International Meeting on Chemical Sensors Fasching, R. J., Tao, Y., Prinz, F. B. ELSEVIER SCIENCE SA. 2005: 964–72

  View details for DOI 10.1016/j.snb.2004.10.058

  View details for Web of Science ID 000230330300158

• Ultra-sharp high-aspect-ratio probe array for SECM and AFM analysis Smart Structures and Materials 2004 Conference Tao, Y., Fasching, R. J., Primz, F. B. SPIE-INT SOC OPTICAL ENGINEERING. 2004: 431–442

  View details for DOI 10.1117/12.547655

  View details for Web of Science ID 000223715800046

• Fabrication of an electrochemical tip-probe system embedded in SiNx-cantilevers for simultaneous SECM and AFM analysis Conference on Micromachining and Microfabrication Process Technology IX Fasching, R. J., Tao, Y., Prinz, F. B. SPIE-INT SOC OPTICAL ENGINEERING. 2004: 53–64

  View details for Web of Science ID 000189447200008

• A miniaturized amperometric CO2 sensor based on dissociation of copper complexes 9th International Meeting on Chemical Sensors Fasching, R., Kohl, F., Urban, G. ELSEVIER SCIENCE SA. 2003: 197–204

  View details for DOI 10.1016/S0925-4005(03)00176-X

  View details for Web of Science ID 000184265500028

• High-density multi-layer connection technology for MEMS and CMOS applications Conference on Smart Sensors, Actuators, and MEMS Bai, S. J., Fasching, R. J., Prinz, F. B. SPIE-INT SOC OPTICAL ENGINEERING. 2003: 536–542

  View details for Web of Science ID 000184053200061

• A pencil probe system for electrochemical analysis and modification in nanometer dimensions Conference on Smart Sensors, Actuators, and MEMS Fasching, R. J., Tao, Y., Hammerick, K., Prinz, F. B. SPIE-INT SOC OPTICAL ENGINEERING. 2003: 128–135

  View details for Web of Science ID 000184053200016