(123g) Synthesis and Characterization of Elastin-Like Polypeptide and Polyelectrolyte Conjugates for Tissue Engineering

Steatohepatitis and other metabolic disorders are a growing problem across the United States, contributing to a wide range of pathologies such as stroke, atherosclerosis, and progressive liver failure. Attempts to construct an adequate in vitro model simulating metabolic dysfunction have been inadequate due to brief survival of explanted hepatic and adipose cells and lack of physiologically-relevant behavior believed to be related to lack of appropriate cellular organization. It is hypothesized that cells arranged into three-dimensional spheroids will show enhanced activity and survival versus those grown on conventional two-dimensional cultures. In the current study, elastin-like polypeptide (ELP) was used as a substrate material due to its biocompatibility, tailored physiochemical properties, and ease of chemical modification. Polyelectrolytes including polyethyleneimine (PEI), poly-L-lysine, and poly-L-arginine were covalently bound to ELP by amide coupling reactions and characterized using a variety of qualitative and quantitative techniques such as DSC, FT-IR, HPLC, SDS-PAGE, and ninhydrin assay. Tissue culture polystyrene plates were coated with the ELP-PEs and seeded with 3T3-L1 and H35 rat hepatoma cells to assess the cell response to the modified surfaces. Modifying the charge of the ELP molecules via conjugated polyelectrolytes was found to induce cultured hepatic and adipose cells to form three-dimensional spheroids relative to the histological organization found in vivo.