Apatite-Forming Ability and Visible Light-Enhanced Antibacterial Activity of CuO-Supported TiO 2 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 (H 2 O 2 ), copper acetate (Cu(OAc) 2 ), and heat (H 2 O 2 -Cu(OAc) 2 -heat) treatments, a network structure of anatase and rutile titanium dioxide (TiO 2 ) 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 H 2 O 2 -Cu(OAc) 2 -heat-treated samples showed that hydroxyl radicals (·OH) were generated from the samples, and the concentration of ·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 ·OH from samples. These results suggest that Ti implants obtained using H 2 O 2 -Cu(OAc) 2 -heat treatments and subjected to regular or on-demand visible-light irradiation may provide a decreased risk of peri-implantitis.