Efficient and toxicity-free surface immobilization of nano-hydroxyapatite for bone-regenerative composite scaffolds by grafting polyvinyl pyrrolidone

► nHA with surface carbonyl functionality was synthesized safely through PVP-grafting synthesis. ► PVP-grafting provides nHA with effective colloidal stability and surface reactivity. ► Nano-level uniform dispersing and chemical-linkage immobilization of nHA on the surfaces of composite scaffolds was realized.