Singlet Oxygen Generation Photocatalyzed by TiO2 Particles and Its Contribution to Biomolecule Damage
The study of near-infrared emission has shown that singlet oxygen ( 1 O 2 ) is generated via superoxide by the photocatalytic reaction of titanium dioxide (TiO 2 ) dispersed in solvents. The 1 O 2 was deactivated on the TiO 2 surface and could not oxidize nicotinamide adenine dinucleotide, which has no affinity to the TiO 2 surface. The generation of photocatalytic 1 O 2 was enhanced in the phospholipid membrane, and a water soluble protein acted as an effective scavenger of the generated 1 O 2 . These findings suggest that 1 O 2 generated by TiO 2 contributes to the phototoxic effect through the oxidation of the membrane protein.