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@WO 3 ) nanostructures — a derivative of tungsten oxide — were investigated. Ag@WO 3 nanostructures synthesized via facile one-pot hydrothermal method have an optical bandgap of [Formula: see text][Formula: see text]eV, nanoflake (NF) size range of 20–70[Formula: see text]nm, a large surface area and a large pore volume. The antibacterial activity of Ag@WO 3 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@WO 3 NFs. Ag-decorated WO 3 NFs exhibit enhanced antibacterial activity compared to the pristine WO 3 NFs. Among them, the 5[Formula: see text]wt.% Ag-decorated sample shows the highest activity against S. aureus while the 7[Formula: see text]wt.% Ag-decorated sample shows the highest activity against E. coli. With 200[Formula: see text]ppm of 5[Formula: see text]wt.% Ag-decorated sample and 500[Formula: see text]ppm of 7[Formula: see text]wt.% Ag-decorated sample, all S. aureus and E. coli were eliminated within 2[Formula: see text]h, respectively. Under the visible light irradiation, the antibacterial activity of Ag-decorated samples was further enhanced. With only 100[Formula: see text]ppm of 5[Formula: see text]wt.% and 7[Formula: see text]wt.% Ag-decorated samples, 99.1% of S. aureus and 100% of E. coli were eliminated after 2[Formula: see text]h, respectively. The evaluation of cytotoxicity of Ag@WO 3 nanoflakes on the human hepatoma cell line (HepG2) indicated that Ag@WO 3 was noncytotoxic to the cells. These results suggest the promising potential of Ag@WO 3 nanocomposites for medical and environmental applications.