Advancements in biomaterials and biofabrication for enhancing islet transplantation

Type 1 diabetes (T1D) is characterized by the degeneration of insulin-producing beta cells within pancreatic islets, resulting in impaired endogenous insulin synthesis, which necessitates exogenous insulin therapy. Although intensive insulin therapy has been effective in many patients, a subset of individuals with unstable T1D encounter challenges in maintaining optimal glycemic control through insulin injections. Pancreatic islet transplantation has emerged as a promising therapeutic alternative for such patients, offering enhanced glucose regulation, reduced risk of complications, and liberation from exogenous insulin reliance. However, impediments such as immune rejection and the need for an optimal transplantation environment limit the success of islet transplantation. Revascularization, a crucial requirement for proper islet functionality, poses a challenge in transplantation settings. Biomaterialbased biofabrication approaches have attracted considerable attention to address these challenges. Biomaterials engineered to emulate the native extracellular matrix provide a supportive environment for islet viability and functionality. This review article presents the recent advancements in biomaterials and biofabrication technologies aimed at engineering cell delivery systems to enhance the efficacy of islet transplantation. Immune protection and vascularization strategies are discussed, key biomaterials employed in islet transplantation are highlighted, and various biofabrication techniques, including electrospinning, microfabrication, and bioprinting, are explored. Furthermore, the future directions and challenges in the field of cell delivery systems for islet transplantation are discussed. The integration of appropriate biomaterials and biofabrication methods has significant potential to promote successful islet transplantation by facilitating vascularization and bolstering the immune defense mechanisms.