Ag Nanoparticles Connected to the Surface of TiO₂ Electrostatically for Antibacterial Photoinactivation Studies

Supported silver nanoparticles (Ag NPs) were prepared by chemical reduction method with a sol-gel method. The structure, morphology, and interconnectivity of Ag/TiO₂ nanocomposites (NCs) were analyzed using different instrumental techniques. Transmission electron microscopy reveals the Ag NPs have uniformly distributed and anchored on the surface of TiO₂ . The reduction in electron-hole recombination was measured by Photoluminescence measurements lead, to an increased photocatalytic inactivation of bacteria. Increase in the amount of Ag NPs on TiO₂ resulted in a slight decrease in optical band gap energy of TiO₂ . The effect of Ag NPs content on the photocatalytic properties of TiO₂ for inhibition of bacteria in visible light irradiation was studied. Furthermore, the antibacterial activity of Ag/TiO₂ NCs in the presence of UVA light was studied against gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacterial strain by plate count method. Lower values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the catalysts were observed and used to determine the tolerance factor which is shown bactericidal nature of the NCs. Subsequently, time-killing assay of Ag/TiO₂ NCs was shown dynamics of antimicrobial activity. These multifold antibacterial studies exhibited potent antibacterial nature of the NCs and employed in the wider range of biomedical fields.