Biomimetic growth of apatite on electrolytic TiO2 coatings in simulated body fluid

Titanium and titanium alloys for implants have been widely applied to the orthopaedic and dental fields, due to their excellent corrosion resistance, good mechanical properties and biocompatibility. However, the near bioinert and metallic ions release are still the major problems in the clinical failure. For these reasons, modification of biomaterials surface properties, which support bioactivity and corrosion resistance, should be one of the key objectives in the design of the next generation of orthopaedic/dental implants. Cathodic electrolytic deposition of anatase TiO₂ coating has been successfully deposited on pure titanium substrate. After annealed at 300 °C for 1 h, the coating were further condensed into anatase TiO₂, and gradually transformed into rutile TiO₂ at 500 °C. The dynamic cyclic polarization tests indicated that dense and nanocrystalline anatase TiO₂ coated effectively improved corrosion resistance to avoid aggression of fluoride ion. For immersion tests, the matching structure of anatase TiO₂ and apatite may play an important role in the apatite formation ability. Moreover, the cell culture results also indicated that nanocrystalline anatase TiO₂ not only promoted cells differentiation, but also appeared more bioactive while maintaining non-toxicity. Obviously, the materials characteristics such as crystal structure, surface morphology and corrosion resistance may play an important role in the osteointegration.