Enhancement of critical-sized bone defect regeneration by magnesium oxide-reinforced 3D scaffold with improved osteogenic and angiogenic properties

•3D bio-nanocomposite scaffold which have an ideal magnesium ionic microenvironment was developed for critical-sized bony tissue repairing.•Significantly enhanced osteogenic effects were observed over the bio-nanocomposite as compare to the polycaprolactone control.•The rodent femoral and critical-sized cranial defect models were applied to characterize the osteogenesis in vivo.•Magnesium enriched scaffold exhibited remarkably increased bone volume, enhanced angiogenesis, and almost recovered critical-sized defect after an 8-week implantation.