Microencapsulation of islets with living cells using polyDNA-PEG-lipid conjugate.

Microencapsulation of islets with a semipermeable membrane, i.e., bioartificial pancreas, is a promising way to transplant islets without the need for immunosuppressive therapy for insulin-dependent diabetes mellitus (type I diabetes). However, materials composing a bioartificial pancreas are not ideal and might activate defense reactions against foreign materials. In this study, we propose an original method for microencapsulation of islets with living cells using an amphiphilic poly(ethylene glyocol)-conjugated phospholipid derivative (PEG-lipid) and DNA hybridization. PolyA and polyT were introduced onto the surfaces of the islets and HEK 293 cells, respectively, using amphiphilic PEG-lipid derivatives. PolyA20 modified HEK cells were immobilized onto the islet surface where polyT20-PEG-lipid was incorporated. The cells spread and proliferated on the islet surface, and the islet surface was completely encapsulated with a cell layer after culture. The encapsulated islets retained the ability to control insulin release in response to glucose concentration changes.