Antibacterial activity of photocatalytic TIO2 spherical particles with 100–200 nm sizes synthesized by the peroxo method

Background. The development of photocatalysts with antibacterial properties seems to be relevant for combating multiresistant microorganisms in medical institutions. Recently, the peroxo method has been used to synthesize semiconducting metal dioxide TiO 2 in the form of spherical particles (SPs) with size of 100–200 nm; its antibacterial properties have not been studied. The aim is evaluation of the survival and morphology of Escherichia coli and Staphylococcus aureus after exposure of the TiO 2 SPs, and estimation their toxicity in bioluminescence test. Methods. TiO 2 at 0.5–2 g/L concentrations after 10-120 min UV irradiation were added to E. coli or S. aureus suspension. Survival, microscopic examination (SEM, ASM), and toxicity bioluminescence test were made after 60–90 min contact. R esults. T he antibacterial effect of TiO 2 SP s w as maintained after UV irradiation was stopped. TiO 2 at 0.5–2 g/L with UV pre-irradiation (120 min) decreased the viability of both E. coli and S. aureus. According to the bioluminescence test, EC50 for TiO 2 SP s w as 7.46, 2.61, 1.87 g/L after 10, 60, 120 min UV pre-irradiation, respectively. The electron microscopic observations suggested that TiO 2 SP s have adhesion and adherence to E. coli and S. aureus cells after UV pre-irradiation. Conclusion. Understanding TiO 2 SP s int er action with bacteria allows development of new photocatalysts with antibacterial properties.