Apatite-Forming Ability and Visible Light-Enhanced Antibacterial Activity of CuO-Supported TiO2 Formed on Titanium by Chemical and Thermal Treatments

Titanium with apatite-forming ability as well as antibacterial activity is useful as a component of antibacterial dental implants. When Ti was subjected to hydrogen peroxide (H2O2), copper acetate (Cu(OAc)(2)), and heat (H2O2-Cu(OAc)(2)-heat) treatments, a network structure of anatase and rutile titanium dioxide (TiO2) and fine copper oxide (CuO) particles was formed on the Ti surface. The resulting samples accumulated a dense and uniform apatite layer on the surface when incubated in simulated body fluid and showed enhanced antibacterial activity against Escherichia coli and Staphylococcus aureus under visible-light irradiation. Electron spin resonance spectra of H2O2-Cu(OAc)(2)-heat-treated samples showed that hydroxyl radicals (<middle dot>OH) were generated from the samples, and the concentration of <middle dot>OH increased with increasing Cu concentration of the Cu(OAc)(2) solution. The enhanced antibacterial activity of these samples under visible-light irradiation may be attributable to the generation of <middle dot>OH from samples. These results suggest that Ti implants obtained using H2O2-Cu(OAc)(2)-heat treatments and subjected to regular or on-demand visible-light irradiation may provide a decreased risk of peri-implantitis.