Antimicrobial Mechanism and Biosafety Evaluation of PdO Modified WO3

Abstract

In this study, PdO loaded WO3 composite was synthesized by precipitation method, followed by calcination. The as-synthesized composite was characterized and the photocatalytic disinfection of Escherichia coli was tested under visible light-irradiation. The characterization results showed that the PdO nanoparticles decorated on the surface of the WO3. The antibacterial test demonstrated that the as-synthesized material with 100:1 mole ratio of W:Pd and calcined at 200°C have the highest efficiency. After visible light irradiation of a short time, about 25 min, almost all of the tested E. coli cells were inactivated. Antimicrobial mechanism, revealed by scavengers of reactive oxygen species, demonstrated that the antibacterial activity was primarily due to the oxidation of photo-generated hole. And the oxidation-reduction reaction of superoxide radical and hydroxyl free radicals were assisted for the photo-disinfection of bacteria. Furthermore, the biosafety of the PdO/WO3 composite was evaluated by analysing the viability of Chinese hamster lung (V79) cells using Cell Counting Kit-8 (CCK-8).