Photocatalytic TiO₂ particles confer superior antibacterial effects in a nutrition-rich environment: an in vitro study

抄録

Titanium dioxide (TiO₂) is known to confer photocatalytic bactericidal effects under ultraviolet (UV) irradiation. Few reports are available, however, on the clinical applications of TiO₂ particle mixtures. Our objective in the present research was to evaluate the in vitro bactericidal effects of a TiO₂ particle mixture in a nutrition-rich biological environment. A bacterial suspension of Staphylococcus aureus and epidermidis 3 × 10³ CFU/mL was added to a TiO₂ particle mixture (0.038 mg/mL) containing mainly sodium percarbonate and citric acid. To simulate a biological environment, 40 μL of 10% bovine serum albumin was added and the culture temperature was maintained at 37°C. The resulting product was irradiated by UV light and the bacterial survival rate was calculated for each time of UV irradiation. In the control sample treated with distilled water + UV, the bacteria survived at a high rate even after 180 min. In the TiO₂ mixture + UV sample, meanwhile, the bacterial survival rate dropped to 43.8% and 6.0% of the baseline values in S. aureus and S. epidermidis, respectively, after 60 min of UV irradiation. The photocatalytic antibacterial action of the TiO₂ particle mixture was high even in a protein-rich biological environment.