Enhanced biological responses of a hydroxyapatite/TiO₂ hybrid structure when surface electric charge is controlled using radiofrequency sputtering

Abstract

We investigated whether surface roughness and control of surface electric charge of a hydroxyapatite (HA)/titanium oxide (TiO₂) hybrid coating could enhance biological responses associated with bone formation. After acid etching, a titanium surface was modified with HA and TiO₂ by the dual sputtering deposition technique using radiofrequency sputtering. These surfaces were analyzed for surface roughness and surface electric charge intensity. Rat bone marrow-derived osteoblast-like cells were cultured on HA/TiO₂ hybrid surfaces with different electric charges. The attachment and spreading behavior of these cells were significantly increased on the hybrid surface (p<0.05). In vivo experiment, the strength of bone-titanium implant integration with a hybrid surface was 3 times that of a control (p<0.05). The dual sputtering deposition technique created a HA/TiO₂ hybrid structure. Our results show that the surface electric charge on a titanium surface is an important factor for enhancing biological responses.