TiO2 photocatalysis causes DNA damage via fenton reaction-generated hydroxyl radicals during the recovery period.

Here, we show that resistance of Escherichia coli to TiO2 photocatalysis involves defenses against reactive oxygen species. Results support the idea that TiO2 photocatalysis generates damage which later becomes deleterious during recovery. We found this to be partly due to DNA attack via hydroxyl radicals generated by the Fenton reaction during recovery.

The bactericidal effect of TiO2 photocatalysis involves adsorption onto catalyst and the loss of membrane integrity.

The bactericidal effect of photocatalysis with TiO2 is well recognized, although its mode of action is still poorly characterized. It may involve oxidation, as illuminated TiO2 generates reactive oxygen species. Here we analyze the bactericidal effect of illuminated TiO2 in NaCl-KCl or sodium phosphate solutions.