Tissue engineering and regenerative medicine has gradually evolved as a promising therapeutic strategy to the modern health care of aging and diseased population. In this study, we developed a novel nanofibrous scaffold and verified its application in the critical bone defect regeneration. The metformin-incorporated nano-gelatin/hydroxyapatite fibers (NGF) was produced by electrospinning, cross-linked, and then characterized by X-ray powder diffractometer and Fourier-transform infrared spectroscopy. Cytotoxicity, cell adhesion, cell differentiation, and quantitative osteogenic gene and protein expression were analyzed by bone marrow stem cells (BMSCs) from rat. Rat forearm critical bone defect model was performed for the in vivo study. The NGF were characterized by their porous structures with proper interconnectivity without significant cytotoxic effects; the adhesion of BMSCs on the NGF could be enhanced. The osteogenic gene and protein expression were upregulated. Postimplantation, the new regenerated bone in bone defect was well demonstrated in the NGF samples. We demonstrated that the metformin-incorporated NGF greatly improved healing potential on the critical-size bone defect. Although metformin-incorporated NGF had advantageous effectiveness during bone regeneration, further validation is required before it can be applied to clinical applications. Impact statement Bone is the structure that supports the rest of the human body. Critical-size bone defect hinders the regeneration of damaged bone tissues and compromises the mechanical strength of the skeletal system. Characterized by their porous structures with proper interconnectivity, the electrospinning nano-gelatin/hydroxyapatite fibrous scaffold developed in this study can greatly improve the healing potential on the critical-size bone defect. Further validation can validate its potential clinical applications.
Keywords: bone tissue regeneration; critical-size bone defect; metformin; nano-gelatin/hydroxyapatite fiber.