ABSTRACT
Several different types of systems employing selectively permeable membranes and matrix supports for cells have been successfully tested in animals. Results in diabetic animals indicate that these systems can function for periods of several months to several years without the use of any of immunosuppression. This approach has the potential not only to allow the transplantation of islets across wide species barriers but that it can be achieved using injectable microreactors fabricated from biodegradable polymers. A new prototype of minimal volume alginate/polyaminoacidic microcapsules which retain immunoisolatory, biocompatibility and functional properties that seem to match those of conventional-size microcapsules was developed. Since coherent microcapsules tightly envelop each islet, any redundant space between membrane and islet is virtually eliminated. Consequently, these microcapsules occupy an extremely this space, thus addressing a major problem associated with conventional size microspheres.
