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

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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 Staph-ylococcus aureus and epidermidis 3 × 103CFU/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.