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The non-β endocrine cells in pancreatic islets play an essential counterpart and regulatory role to the insulin-producing β-cells in the regulation of blood-glucose homeostasis. While significant progress has been made towards the understanding of β-cell regeneration in adults, very little is known about the regeneration of the non-β endocrine cells such as(More)
We report the synthesis of a new class of recombinant elastin-mimetic triblock copolymer capable of both physical and chemical crosslinking. These investigations were motivated by a desire to capture features unique to both physical and chemical crosslinking schemes so as to exert optimal control over a wide range of potential properties afforded by(More)
Chemical approaches to cell surface engineering have emerged as powerful tools for resurfacing the molecular landscape of cells and tissues. Here we report a new strategy for re-engineering cell surfaces through electrostatic adsorption of appropriately structured and functionalized poly(l-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) copolymers to(More)
Artificial composites designed to mimic the structure and properties of native extracellular matrix may lead to acellular materials for soft tissue repair and replacement, which display mechanical strength, stiffness, and resilience resembling native tissue. We describe the fabrication of thin lamellae consisting of continuous collagen microfiber embedded(More)
Encapsulation of cells and tissue offers a rational approach for attenuating deleterious host responses toward transplanted cells, but a need exists to develop cell encapsulation strategies that minimize transplant volume. In this report, we describe the formation of nanothin, PEG-rich conformal coatings on individual pancreatic islets via layer-by-layer(More)
Layer-by-layer assembly of polyelectrolyte multilayer (PEM) films represents a bottom-up approach for re-engineering the molecular landscape of cell surfaces with spatially continuous and molecularly uniform ultrathin films. However, fabricating PEMs on viable cells has proven challenging owing to the high cytotoxicity of polycations. Here, we report the(More)
BACKGROUND CD39 (nucleoside triphosphate diphosphohydrolase [NTPDase-1]) expressed on the luminal surface of endothelial cells rapidly metabolizes extracellular adenosine triphosphate (ATP) and adenosine diphosphate (ADP) to adenosine monophosphate (AMP), and abrogates platelet reactivity. Optimization of CD39 enzymatic activity appears dependent upon the(More)
Peptide amphiphile (PA) is a peptide-based biomaterial that can self-assemble into a nanostructured gel-like scaffold, mimicking the chemical and biological complexity of natural extracellular matrix. To evaluate the capacity of the PA scaffold to improve islet function and survival in vitro, rat islets were cultured in three different groups--(1) bare(More)
A new class of high molecular weight polysulfated PEO dendrimer-like glycopolymer has been synthesized by a combination of arm-first and core-first methodologies followed by trichloroacetimidate glycosidation as a facile bioconjugation strategy. An L-selectin antagonist was identified that exhibits 103-fold greater activity than other multivalent sLex(More)
The success rate of subcutaneous transplantation of pancreatic islets has been extremely low. Insufficient oxygen supply to the grafted islets is one possible major obstacle to the preservation of graft function. This study attempted to use basic fibroblast growth factor (bFGF) in subcutaneous transplantation to induce neovascularization and a sufficient(More)