A thin disc-shaped macrocapsule for transplantation of oxygen carrier-laden alginate hydrogel-encapsulated pancreatic islets in diabetic mice

Abstract

Pancreatic islet encapsulation has long been considered as a groundbreaking solution capable of reducing dependence on lengthy immune suppression protocols while boosting the receptivity of transplanted cells. However, its efficiency is still limited by insufficient oxygenation due to the distance to access the nearest blood supply and oxygen. During the treatment period with macrocapsules, before the effectiveness results are achieved, its negative effects will be limiting; therefore, it will affect its potential applications in the future. In our efforts to overcome existing obstacles, we encapsulated pancreatic islets into alginate hydrogel enriched by perfluorooctylbromide (PFOB) as oxygen carriers within the core of a disc-shaped macrocapsule. Physicochemical properties and biocompatibility tests were done on the designed device and then macrocapsules carrying pancreatic islets were transplanted into the peritoneal cavity of streptozotocin-induced diabetic mice and monitored for five weeks. Surprisingly, the results verified normal fast blood glucose (FBG) levels, and intraperitoneal glucose tolerance testing (IP-GTT) confirmed proper transplanted islet functionality during this time after transplantation. Our findings showcased benefits realized through implementing PFOB in alginate hydrogel by significantly increasing the oxygen supply throughout encapsulated pancreatic islets and also creating a conducive immunoprotective environment along with successful vascularization for sustained survival post-implantation.