Synergistic Effects of Graphene Oxide and Vascular Endothelial Growth Factor Immobilized in Polycaprolactone Nanofiber as a Candidate for Diabetic Wound Healing

   Background & Objective: The combination of two or more therapeutic agents and their synergetic impacts can be therapeutically effective against multifactorial diseases, such as diabetic foot ulcers. This study demonstrates the application of a nanofiber-based drug delivery system with a controlled release of the growth factor. Various studies have shown that vascular endothelial growth factor (VEGF) stimulates angiogenesis via the VEGF signaling pathway and graphene oxide (GO) has been reported to possess antibacterial property. Therefore, VEGF and GO are hypothesized to have wound-healing effects when used synergistically.  Materials & Methods:  In this study, VEGF was purified and verified by western blotting. GO and polycaprolactone (PCL) were prepared by electrospinning and were characterized by scanning electron microscope. Next, VEGF was immobilized by EDC/NHS linker in PCL-GO. Staphylococcus aureus and Escherichia coli were used to evaluate the antibacterial property of GO. Biodegradation and other release properties of the nanofibers were assessed. Moreover, the nanofibers were studied for cell viability and gene expression using human umbilical vein endothelial cells.  Results:  The re-analysis of the protein-protein interaction network from the GO database confirmed the centrality of the nitric oxide synthase 3 (eNOS) showing its effects on the expression of other proteins. In addition, the PCL-GO nanofiber loaded with VEGF was studied for the expression of the eNOS gene in the VEGF signaling pathway. It was observed that PCL-GO-VEGF led to an increased expression of the eNOS gene in two weeks.  Conclusion:   Based on the observed antibacterial property and angiogenesis influence, PCL-GO-VEGF can be considered as a candidate to promote diabetic wound healing.