Photocatalytic bactericidal action of fluorescent light in a titanium dioxide particle mixture: an in vitro study

Traditional titanium dioxide (TiO2) has photocatalytic bactericidal properties only under ultraviolet (UV) irradiation, which restricts its use in clinical treatment regimens. In this study, we evaluated the photocatalytic bactericidal effects of an aqueous system of TiO2 particles irradiated by fluores - cent light (FL) on Staphylococcus aureus. A TiO2 particle mixture containing 19 ppm (0.019 mg/ mL) of TiO 2 was prepared. A bacterial solution of 1 × 10 5 CFU/mL was added one drop at a time to the TiO2 mixture. The resulting product was then irradiated with FL. The bacterial survival rate decreased steadily in the TiO2 mixture group, reaching 76.7% after 30 min of FL irradiation and 10.9% after 60 min. After 60 to 180 min, the bacterial survival ratio of the TiO2 mixture group was significantly lower than that of the control group ( P < 0.05). The present study indicates that treating the surfaces of surgical devices and the surgical field with a TiO 2 particle mixture can cre- ate a nearly sterile environment that can be maintained throughout surgery, even at low luminous intensities.