Preparation and bioactivity of TiO2 nanotubes exposed with highly active facets

TiO2 nanotubes arrays with dominant (001) facets were fabricated by multi-anodic oxidation technology. The influence factor of the electrolyte composition on the ratio of different facets for anatase TiO2 and the bioactivity were investigated. Besides, the characterization of the surface morphologies and crystal structures were analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD),etc. Finally, the bioactivity was estimated by the CaP salt deposition vis biomineralization process and protein adsorption experiment. The results show that the relative proportions of different facets in the TiO2 nanotubes can be adjusted by changing the content of H2O in the electrolyte. The (004) facet texture coefficient of TiO2 nanotubes arrays prepared in 2%H2O (volume fraction) electrolyte reaches up to 4.76. The TiO2 nanotubes with dominant (001) facets can accelerate the deposition of hydroxyapatite and raise the amount of protein adsorption in the humanoid environment by providing more active sites for biomineralization and protein adsorption. The TiO2 nanotubes with a higher proportion of (001) facets have the more excellent biological activity.