Near-field electrospun PCL fibers/GelMA hydrogel composite dressing with controlled deferoxamine-release ability and retiform surface for diabetic wound healing

Wound ulceration caused by diabetes is a typical chronic wound wherein healing the local tissue is difficult due to lack of blood vessels and tissue necrosis caused by the long-term accumulation of free radicals. Near-field electrospinning (NFES) is an innovative technology used to produce micro-nano-scaled, controllable sequencing fibers. In this study, we constructed a novel wound dressing based on the NFES polycaprolactone (PCL) fiber network and modified gelatin with methacrylic anhydride (GelMA) hydrogel to promote angiogenesis and the re-epithelialization of diabetic wounds. An angiogenic and antioxidant drug named deferoxamine (DFO) was encapsulated in a GelMA hydrogel to achieve a slow-release effect that is more suitable for chronic wounds. The cell adhesion experiment showed that the cells could attach to the fibers in the dressing group having a network of PCL fibers on the surface and grow along the direction of the fibers, which in turn, effectively regulates cell behavior from the physical structure. Additionally, the large pore size (∼ 500 µm) of the network allowed the cells to penetrate the pores and enter the surface of the hydrogel without being blocked out. Besides, the composite dressing had a notable effect on angiogenesis. Furthermore, antioxidation experiments confirmed that the DFO-loaded hydrogel exhibited antioxidant activity. Experimental animal models of diabetes showed that rats treated with the PCL-GelMA-DFO (PGD) hydrogel had faster ability of hemostasis, scab formation, and wound healing. In conclusion, the PGD hydrogel effectively promoted the repair of chronic wounds.