Dopamine-assisted immobilization of hydroxyapatite nanoparticles and RGD peptides to improve the osteoconductivity of titanium.

Hydroxyapatite (HAp) coating on orthopedic implants is a common strategy to increase osteointegration. In this work, a facile deposition method based on dopamine polymerization was developed for preparation of HAp-coated titanium substrates for orthopedic applications. Nanostructured HAp was mixed with an alkaline dopamine solution and then deposited onto titanium to form a dopamine/HAp ad-layer. The deposition of dopamine/HAp greatly enhanced the adhesion, proliferation, and mineralization of osteoblasts. Furthermore, RGD-containing peptides were immobilized to dopamine/HAp coated titanium and further enhanced cell adhesion and osteogenic differentiation. In conclusion, this facile dopamine-assisted surface modification method shows a great potential for orthopedic and dental applications.