Hypoxia-Mimicking Cobalt-Doped Borosilicate Bioactive Glass Scaffolds with Enhanced Angiogenic and Osteogenic Capacity for Bone Regeneration.

The osteogenic capacity of synthetic bone substitutes is will be highly stimulated by a well-established functional vascularized network. Cobalt (Co) ions are known that can generate a hypoxia-like response and stimulates the production of kinds of angiogenic factors. Herein, we investigated the mechanism of cobalt-doped bioactive borosilicate (36BO, 22CaO, 18SiO, 8MgO, 8KO, 6NaO, 2PO; mol%) glass scaffolds for bone tissues repairing and blood vessel formation in the critical-sized cranial defect site of rats and their effects on the hBMSCs were researched. The scaffolds can control release Co ions and convert into hydroxyapatite soaking in simulative body fluids (SBF). The fabircated scaffolds without cytotoxic strongly improves HIF-1α generation, VEGF protein secretion, ALP activity and upregulates the expression of osteoblast and angiogenic relative genes in hBMSCs. Eight weeks after implantation, the bioactive glass scaffolds with 3wt % CoO remarkablely enhance bone regeneration and blood vascularized network at the defective site. In conclusion, as a graft material for bone defects, low-oxygen simulated cobalt-doped bioactive glass scaffold is promising.