Photocatalytic inactivation of influenza virus by titanium dioxide thin film

Abstract

Titanium dioxide (TiO2) under ultraviolet (UV) light produces a strong oxidative effect and may therefore be used as a photocatalytic disinfectant. Although many studies on the photocatalytic inactivation of bacteria have been reported, few studies have addressed virus inactivation. In the present study, we demonstrated the inactivation of influenza virus through TiO2 photocatalysis using TiO2 nanoparticles immobilized on a glass plate. The influences of the UV intensity, UV irradiation time and bovine serum albumin (BSA) concentration in the viral suspensions on the inactivation kinetics were investigated. Additionally, we also determined whether the International Organization for Standardization (ISO) methodology for the evaluation of antibacterial activity of TiO2 photocatalysis could be applied to the evaluation of antiviral activity. The viral titers were dramatically reduced by the photocatalytic reaction. Even with a low intensity of UV-A (0.01 mW cm-2), a viral reduction of approximately 4-log 10 was observed within a short irradiation time. The viral inactivation kinetics were associated with the exposure time, the UV intensity and the BSA concentration in virus suspensions. These results show that TiO 2 photocatalysis could be used to inactivate the influenza virus. Furthermore, a minor modification of the ISO test method for anti-bacterial effects of TiO2 photocatalysis could be useful for the evaluation of antiviral activity. © 2012 The Royal Society of Chemistry and Owner Societies.