Bioartificial pancreas: Challenges and progress

The principle of the bioartificial pancreas is based on immunoisolation of insulin-producing cells in immunoprotective but semipermeable capsules that protect cells from the host immune system. Three concepts are currently being developed into clinically applicable devices: intravascular macrocapsules, extravascular macrocapsules, and microcapsules. These approaches are critically reviewed in the view of future clinical application. Much progress has been made in the development of suitable biomaterials for this field of application. Emerging developments are the application of antibiofouling polymers as well as application of polymer brushes and immunomodulatory biomaterials that elicit minimal or no tissue responses. Challenges that remain are finding means to support the longevity of tissues in the capsules. Conceivable approaches to support this are inclusion of cell-death inhibitors as well as extracellular matrix molecules. A replenishable cell source is needed to start efficacy studies in humans.