Physicochemical analyses of alginates and alginate-poly-L-lysine-alginate microcapsules for the improvement of microcapsule biocompatibility.

摘要

The only treatment for insulin-dependent diabetes mellitus (IDDM) that can induce constant normoglycemia and insulin independence is the transplantation of a pancreas or of pancreatic cells.; By encapsulating the islet cells within a semi-permeable membrane, they can be protected from the immune system without the use of dangerous immunosuppressive medications. This approach to preventing graft rejection is termed microencapsulation. Microencapsulation consists of immobilizing the islet cells in an alginate-based gel, surrounding the gel bead with a semi-permeable layer of poly-L-lysine (PLL), and then coating the entire capsule with a biocompatible layer of alginate.; The general objective of this project was to explain the in vivo bioreactivity of the alginates and the microcapsules in terms of their physicochemical properties. The specific aims were to: (1) Identify and quantify the contaminants that are present in alginates after purification, (2) Evaluate the effect of these contaminants on the in vivo biocompatibility of the alginates, and (3) Determine the chemical composition of the microcapsule surface. (Abstract shortened by UMI.)