Fig. 1
Mechanism of reactive oxygen species (ROS) generation on the surface of nanoparticles of titanium or zinc oxides (a) and the effects of ROS on infectious agents (b). On the surface of TiO2 and ZnO nanoparticles, exposed to UV radiation, ROS (•O2 −, •OH, and H2O2) are formed (a). ROS have the ability to inactivate infectious agents susceptibility of which to oxidative damages can be arranged in the following order: viruses > prions > Gram(−) bacteria > Gram(+) bacteria > yeasts > molds (b). Subsequently, organic matter and dead microbial cells are oxidized by ROS to CO2 and H2O (b)