Biomimetic processing of nanocrystallite bioactive apatite coating on titanium

Biomimetic processes have attracted huge attention in recent years due to their significant applications in biomedical areas such as bone tissue engineering. In the present study, a biomimetic process was employed to form a nanocrystallite apatite coating on metal. A thin bone-like apatite layer was coated onto titanium (Ti) metals via an alkali pre-treatment. This was followed by immersion in a simulated body fluid. Analysis of the coating by thin film x-ray diffraction and scanning electron microscope has shown that the apatite layer grown in this way exhibits nanostructure and has similar stoichiometry to that of the natural bone. It is observed that the thickness of the apatite layer increases as the immersion period increases. The growth kinetics and mechanism are also discussed. A cross-sectional study has also shown that a uniform coating of carbonate-containing apatite (hydroxyapatite) is firmly adhered on the Ti metal. The adhesion of the apatite layer on the Ti substrate was further confirmed by a shear test, which has shown an average value of 9.5 MPa. The bioactivity of the coating was finally examined by cell culturing experiments. The results have shown that the nanocomposite prepared using the present method possesses good mechanical properties and bioactivity.