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Polydimethylsiloxane (PDMS Sylgard 184, Dow Corning Corporation) pre-polymer was combined with increasing amounts of cross-linker (5.7, 10.0, 14.3, 21.4, and 42.9 wt.%) and designated PDMS1, PDMS2, PDMS3, PDMS4, and PDMS5, respectively. These materials were processed by spin coating and subjected to common micro-fabrication, micro-machining, and biomedical(More)
Silicon micromachining provides the precise control of nanoscale features that can be fundamentally enabling for miniaturized, implantable medical devices. Concerns have been raised regarding blood biocompatibility of silicon-based materials and their application to hemodialysis and hemofiltration. A high-performance ultrathin hemofiltration membrane with(More)
Medical devices based on microelectro-mechanical systems (MEMS) platforms are currently being proposed for a wide variety of implantable applications. However, biocompatibility data for typical MEMS materials of construction and processing, obtained from standard tests currently recognized by regulatory agencies, has not been published. Likewise, the(More)
The nearly 400000 American patients on dialysis suffer high cardiovascular and infectious mortality, but there is now evidence that this morbid phenotype can be rescued by intensive dialytic therapy. Self-care dialysis at home is limited by patient fears about skill and safety. An implanted artificial kidney would provide the benefits of intensive therapy(More)
Over 300,000 Americans are dependent on hemodialysis as treatment for renal failure, and kidney transplantation is limited by scarcity of donor organs. This shortage has prompted research into tissue engineering of renal replacement therapy. Existing bioartificial kidneys are large and their use labor intensive, but they have shown improved survival(More)
The effects of pore size on the performance of ultrafiltration membranes are fairly well understood, but there is currently no information on the impact of pore geometry on the trade-off between the selectivity and permeability for membranes with pore size below 100 nm. Experimental data are presented for both commercial ultrafiltration membranes and for(More)
We have developed a bilayer microfluidic system with integrated transepithelial electrical resistance (TEER) measurement electrodes to evaluate kidney epithelial cells under physiologically relevant fluid flow conditions. The bioreactor consists of apical and basolateral fluidic chambers connected via a transparent microporous membrane. The top chamber(More)
Growth of human connective tissue progenitor cells (CTPs) was characterized on smooth and microtextured polydimethylsiloxane (PDMS) surfaces. Human bone marrow derived cells were cultured for nine days under conditions promoting osteoblastic differentiation on Smooth PDMS and PDMS Channel microtextures (11 microm high, 45 microm wide channels, and separated(More)
The influence of surface microtexture on osteogenesis was investigated in vitro by examining the proliferation and differentiation characteristics of a class of adult stem cells and their progeny, collectively known as connective tissue progenitor cells (CTPs). Human bone marrow-derived CTPs were cultured for up to 60 days on smooth polydimethylsiloxane(More)
Nanotechnology, defined as the science of material features between 10(-9) and 10(-7) of a meter, has received extensive attention in the popular press as proof-of-concept experiments in the laboratory are published. The inevitable delay between feature articles and clinical endpoints has led to unwarranted skepticism about the applicability of the(More)