Accelerated full-thickness wound healing via sustained bFGF delivery based on a PVA/chitosan/gelatin hydrogel incorporating PCL microspheres

Herein, a hybrid hydrogel/microsphere system is introduced for accelerated wound healing by sustained release of basic fibroblast growth factor (bFGF). The hydrogel is composed of a mixture of PVA, gelatin and chitosan. The double-emulsion-solvent-evaporation method was utilized to obtain microspheres composed of PCL, as the organic phase, and PVA, as the aqueous phase. Subsequently, various in-vitro and in-vivo assays were performed to characterize the system. BSA was used to optimize the release mechanism, and encapsulation efficiency in microspheres, where a combination of 3% (w/v) PCL and 1% (w/v) PVA was found to be the optimum microsphere sample. Incorporation of microspheres within the hydrogel substrate also led to a zero-order release kinetics. Results from SEM images, also represented an average porosity of 54%, and average mean pore size of 35 ± 7 μm for the hydrogel system, and the diameter of 5 ± 2 μm for the microspheres. Moreover, in vivo study including wound healing process, and histological analysis regarding re-epithelization, angiogenesis, inflammation, fibroblast genesis and collagen formation were performed using Hematoxyline-Eosin (H&E) staining, Periodic Acid-Schiff (PAS) staining and Masson's Trichrome staining. In-vivo results represented that sustained delivery of bFGF promoted by biocompatibility of PVA/chitosan/gelatin hydrogel, significantly contribute to accelerated wound healing.