Co-encapsulation of pancreatic islets and pentoxifylline in alginate-based microcapsules with enhanced immunosuppressive effects

Alginate-based scaffolds have received considerable attention for biomedical application because of their biocompatibility and ease of preparation. The application of alginate hydrogels for encapsulation of pancreatic islets is known as a potential treatment for type I diabetes. In this study, dextran–spermine coated microcapsules of alginate containing pancreatic islets were prepared, and then co-cultured with lymphocytes for 7 days. In addition, to prevent fibrosis and evaluating the effect of anti-inflammatory drugs, pentoxifylline was loaded in the inner layer of microcapsules. Intact and encapsulated islets in an external solution of pentoxifylline were taken as two separate controls in this study. Infrared and scanning electron microscope analyses showed polyelectrolyte complex formation between alginate and dextran–spermine. In vitro tests showed that interleukin-2 secretion from lymphocytes co-cultured with encapsulated islets containing pentoxifylline in the inner layer of microcapsules was 63.6 % lower than the corresponding value for encapsulated islets without the anti-inflammatory drug.