Enhanced Antibacterial Activities with Low Toxicity of Silver-Decorated Tungsten Oxide Nanoflakes Prepared via Facile Hydrothermal Method.

Metal oxide nanostructures and their derivatives have received significant attention in recent years due to their high potential in enhancing the efficacy of antimicrobial therapies. In this study, the antibacterial activity and toxicity of silver-decorated tungsten oxide (Ag@WO3) nanostructures — a derivative of tungsten oxide — were investigated. Ag@WO3 nanostructures synthesized via facile one-pot hydrothermal method have an optical bandgap of ∼ 2. 7 2 eV, nanoflake (NF) size range of 20–70 nm, a large surface area and a large pore volume. The antibacterial activity of Ag@WO3 NFs was evaluated by assessing the viability of the Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) upon exposure to Ag@WO3 NFs. Ag-decorated WO3 NFs exhibit enhanced antibacterial activity compared to the pristine WO3 NFs. Among them, the 5 wt.% Ag-decorated sample shows the highest activity against S. aureus while the 7 wt.% Ag-decorated sample shows the highest activity against E. coli. With 200 ppm of 5 wt.% Ag-decorated sample and 500 ppm of 7 wt.% Ag-decorated sample, all S. aureus and E. coli were eliminated within 2 h, respectively. Under the visible light irradiation, the antibacterial activity of Ag-decorated samples was further enhanced. With only 100 ppm of 5 wt.% and 7 wt.% Ag-decorated samples, 99.1% of S. aureus and 100% of E. coli were eliminated after 2 h, respectively. The evaluation of cytotoxicity of Ag@WO3 nanoflakes on the human hepatoma cell line (HepG2) indicated that Ag@WO3 was noncytotoxic to the cells. These results suggest the promising potential of Ag@WO3 nanocomposites for medical and environmental applications. The Ag@WO3 nanoflake, synthesized via a one-step hydrothermal method, demonstrated antibacterial activity against E. coli and S. aureus. The effects of concentration and exposure time were evaluated to identify the optimal conditions for antibacterial activity. Notably, the antibacterial efficacy was further enhanced under visible light irradiation. Furthermore, the low toxicity of Ag@WO3 toward HepG2 liver cancer cells highlights its potential for therapeutic applications. [ABSTRACT FROM AUTHOR]