Encapsulation of Langerhans' islets: Microtechnological developments for transplantation

There is an increasing trend to apply microsystems and microfluidics to solve medical and biomedical tasks. Microfluidic modules are used to modify and manipulate cells and cell clusters for therapeutic applications. Specifically, a method and technical system for encapsulation of Langerhans' islets as an option for the future treatment of diabetes mellitus is described. Type-1 diabetes patients suffer from an absolute lack of the hormone insulin caused by an autoimmune process destroying the Langerhans' islets. One way to restore glucose-dependent insulin secretion is the transplantation of human pancreatic islet cells (85% beta cells) from cadaveric donors. However, to prevent the rejection of the transplanted cells by the immune system of the host, a life long immunosuppressive medication is necessary. One possible way to prevent this rejection would be the transplantation of immunoseparated Langerhans' islets, which are encapsulated in a 3D-alginate matrix polymerized with ions like Ba2+. As has been successfully shown in animal experiments, this technique would furthermore allow the transplantation of xenograft islets and thus help to solve the problem of shortage in donor organs. We present a microfluidics-based system for encapsulation of cells in alginate.