Bactericidal performance of photocatalytic titanium dioxide particle mixture under ultraviolet and fluorescent light: an in vitro study

When ultraviolet (UV) light comes into contact with titanium dioxide (TiO2), a variety of free radicals are released to provide a potent oxidizing power. Few reports are available, however, evaluating the bactericidal effects of TiO2 particle under UV light and fluorescent light (FL) in the same line of research for clinical applications. In the present study, we set out to evaluate the in vitro photocatalytic bactericidal effects on Staphylococcus aureus, which is one of the most common pathogens of infectious disease, in an aqueous system of TiO2 particles irradiated by UV and FL. A TiO2 particle mixture containing 0.019 mg/ml of TiO2 was prepared. A bacterial solution was added dropwise to the mixture, and the resulting product was irradiated by UV or FL light. The colony-forming units were counted and the bacterial survival rate was calculated. Control samples maintained a relatively high bacterial survival rate. In the TiO2 mixture group, however, the bacterial survival rate decreased steadily, reaching 9.4% after 60 min of exposure to UV light and 10.9% after 60 min of FL irradiation. Distributing the TiO2 particles in a water mixture produces highly efficient light absorption and enables greater and more frequent adhesion with bacteria, allowing a high degree of photocatalytic antibacterial action. Although the quantity was inferior to UV, our TiO2 particles were able to show effective bactericidal activity even under FL. The TiO2 particle mixture is expected to prove effective in preventing postoperative infection. Copyright © 2009 John Wiley & Sons, Ltd.