Assessment of bone morphogenic protein and hydroxyapatite–titanium dioxide composites for bone implant materials

• HAp–TiO2 coating was synthesized by one step micro-arc-oxidation.
• BMP-2 promotes cell activities in cell adhesion, proliferation and differentiation.
• HAp–TiO2/BMP-2 composite further enhances in-vitro cell activity.

The HAp–TiO2 coating, made by micro-arc oxidation (MAO), is successfully grown on the Ti surface in one step; BMP-2 growth factor is physically immobilized on the HAp–TiO2 coating. The BMP-2/HAp–TiO2 hybrid system outperforms systems of pure Ti, BMP-2/Ti, and HAp–TiO2 by promoting cell adhesion increasing filopodia and polygonal lamellipodia extension, and increasing cell viability. Additionally, cell proliferation and alkaline phosphatase (ALP) activity both indicate that the BMP-2/HAp–TiO2 hybrid system is more successful. According to the characteristics of mechanical support from HAp–TiO2, the BMP-2/HAp–TiO2 hybrid system can maintain a stable release rate of BMP-2 to promote bone cell growth and rapidly heal the bone–implant interface. The new BMP-2/HAp–TiO2 hybrid system developed in this study can be expected to contribute in the application of orthopedic and dental implants.