Structures, bonding strength and in vitro bioactivity and cytotoxicity of electrochemically deposited bioactive nano-brushite coating/TiO2 nanotubes composited films on titanium

The nano brushite/TiO2 nanotubes composited coating with doubled layer structure was fabricated on titanium (Ti) by the multi-step treatments including sandblasting, acid etching, anodic oxidation and electrochemical deposition. The bonding strength of the brushite coating on Ti surface was improved by pre-treatment of the sandblasting, acid etching and anodic oxidation. At the same time, the nano-brushite has a preferred orientation growth on (020) crystal planes due to the good crystallographic matching between brushite and TiO2 on special crystal plane, which probably resulted in the higher bonding strength of the brushite coating with Ti substrate, when TiO2 nanotubes formed as interlayer. In addition, the brushite/TiO2 nanotube composited coatings show super hydrophilicity. In this work, the simulated body fluid incubation and cell activity experiments indicated that the composited coating exhibits excellent apatite-formation ability and cell biocompatibility, showing a potential biomedical application.