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

An effective approach to fabricate porous bone regenerative composite scaffolds with surface-immobilized nano-hydroxyapatite (nHA) is developed in this research. In the typical preparation process, surface-repellent stable colloidal nHA with surface carbonyl functionality was fabricated through in-situ polyvinyl pyrrolidone (PVP)-grafting synthesis without any organic solvents and potentially harmful additives. Followed by freezing and lyophilizing homogenous PVP-grafted nHA and chitosan mixtures, three dimensional nHA and chitosan composite scaffolds were then obtained. The TEM images and XPS analysis show that the discrete nHA was anchored at nano-level on the pore surface of chitosan scaffold by mediating PVP chemical-linkage. The PVP-grafting offers an efficient and safe approach to prepare nHA with the surface reactivity and is promising to be widely used in the fabrication of novel composite scaffolds for bone tissue engineering.