Critical comparison of aerogel TiO2 and P25 nanopowders: Cytotoxic properties, photocatalytic activity and photoinduced antimicrobial/ antibiofilm performance

Abstract

A critical comparison of two TiO2 nanopowders is herein presented. TiO2 aerogel powder synthesized via lyophilization (TiAP) and commercially available TiO2 Evonik (P25) are thoroughly investigated for their toxicity, photoinduced antimicrobial and antibiofilm properties, and photocatalytic activity. Time- and concentration-dependent A549 cell viability inhibition was characterized using estimating the mitochondrial dehydrogenase activity and glutathione levels. Both materials showed low toxicity in the pulmonary A549 cells. Photocatalytic activity of TiAP and P25 in the degradation of methylene blue and caffeine was determined, and TiAP was more efficient than P25 by 1.2-2.8 times. That is due to the 2D morphology of TiAP, along with an increased generation of hydroxyl radicals compared to a system containing 0D P25. Photoinduced antimicrobial and antibiofilm performance of TiAP and P25 on inactivation of gram-negative E. coli and gram-positive E. faecalis showed a complete log 6 reduction in the amount of bacteria after 60 min UV-A irradiation.