(406c) Zwitterionic Hydrogel for Islet Encapsulation

Authors: 
Cao, Z., Wayne State University

Islet Encapsulation using biopolymers is a promising solution for type 1 diabetes by delivering insulin independence without immunosuppressant. Transplanted islets are protected by the outer layer of polymer from being attacked by the host’s immune system and are believed to control blood glucose in a long term. Nevertheless, the major challenge is that the current encapsulation materials can well protect the islets inside, but they became the target of the host’s immune system instead. A process called foreign body reaction can virtually happen on all existing implanted materials where fibrotic tissues (a dense collagenous layer with limited blood supply) was deposited on the implants; this endangers the survival of encapsulated islets due to a lack of blood/oxygen supply and also hinders glucose/insulin transport for the implant to achieve therapeutic function. In this presentation, a novel islet encapsulation technology based on zwitterionic polymer hydrogels will be introduced. Zwitterionic polymeric materials emerged as new generation of materials with excellent non-fouling properties and biocompatibility. It has been demonstrated that their use as surface coatings can effectively resist binding from proteins, cells, and full blood. Recent research demonstrated that a hydrogel material made from zwitterionic carboxybetaine moieties can resist the formation of a fibrotic capsule for at least 3 months after subcutaneous implantation in mice, noting that no other known materials can completely prevent capsule formation. Results will be presented showing the advantage of this zwitterionic based technology over state-of-the-arts, such as alginate based islet encapsulation, in reversing diabetes on a mouse model.