[Effects on the antibacterial activity of TiO(2) nanotubes with different diameters from ultraviolet ray-irradiation]

To study the effects of ultraviolet ray (UV)-irradiation on the surface characteristic and antibacterial activity of TiO(2) nanotubes with different diameters.

TiO(2) nanotubes with different diameters were fabricated on polished pure titanium (PT) samples by anodization at 5, 10 and 20 V with PT as control. The samples were exposed to UV-irradiation for 24 h, then the characteristic and antibacterial activity were analyzed and evaluated. The surface topograph was observed by field emission scanning electron microscope (FE-SEM). Contract angle measurements were carried out with three liquids. Staphylococcus aureus (Sa) were used to evaluate the antibacterial activity of samples with the film contact method. The bacterial morphology was observed by FE-SEM. The bacterial adhesion and cell membrane injury were evaluated by fluorescent staining analysis under laser scanning confocal microscope (LSCM).

After the TiO(2) nanotubes with different diameters were exposed to UV-irradiation, no change was observed in its surface topograph. With the increase of the diameters of nanotubes, each contract angle of nanotubes decreased, and bacterial FIt and dead/live ratio were also increased. We found 20 V FIt was the biggest (26.550 ± 2.940) and ranks the highest ratio of death/live (0.728 ± 0.091) among the others (P < 0.05).

The UV-irradiation can decrease the contract angle of TiO(2) nanotubes and promote the Sa adhesion on nanotubes. Meanwhile, the antibacterial activity of TiO(2) nanotubes with different diameters was remarkably enhanced by UV-irradiation. Nanotubes anodized at 20 V showed the best antibacterial activity.