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 (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 (·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 H₂O₂-Cu(OAc)₂-heat treatments and subjected to regular or on-demand visible-light irradiation may provide a decreased risk of peri-implantitis. [ABSTRACT FROM AUTHOR]