Curcumin-loaded bioadhesive silk fibroin microsphere improves islet transplantation by mitigating oxidative stress and inhibiting apoptosis.

Islet transplantation, a form of cell therapy involving the injection of healthy islet cells into the recipient's body for curative treatment of T1DM, often fails due to oxidative stress and inflammatory damage experienced by the transplanted islets. Curcumin, a naturally occurring polyphenol with potent anti-inflammatory and antioxidant properties, has been underutilized in islet protection due to challenges associated with its co-delivery and formulation. In this study, we developed bioadhesive curcumin microspheres (PDA/CUR@SF) by incorporating curcumin into a silk fibroin matrix and subsequently coating it with polydopamine to enhance islet adherence. Silk protein acts as a delivery carrier while polydopamine serves as an adhesive agent; both components synergistically provide anti-inflammatory effects. In vitro experiments demonstrated that PDA/CUR@SF enhances islet resistance against oxidative stress and inflammatory damage by improving cell viability and function. In vivo studies showed that PDA/CUR@SF prolongs stabilization of blood glucose levels in diabetic mice receiving islet transplantation while facilitating faster glucose clearance. Further analysis revealed that PDA/CUR@SF protects transplanted islets through co-grafting and promotes neovascularization. Overall, our findings suggest that PDA/CUR@SF offers a rational approach to improve outcomes in transplantation.