Optical properties and antibacterial photodynamic performance of Zn-doped β-Ag2WO4 nanostructures

Abstract

Metal oxide nanostructures have attracted increasing attention as inorganic photosensitiz ers for photodynamic inactivation (PDI) due to their optical stability and ability to gener ate reactive oxygen species under light irradiation. In this work, zinc-doped β-Ag2WO4 nanostructures were synthesized via a co-precipitation chemical method and systematical ly characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), pho toluminescence spectroscopy, and zeta potential analysis. The synthesized nanoparticles exhibited a hexagonal β-phase structure with particle sizes in the range of 50–80 nm. Pho toluminescence measurements revealed emission bands in the blue-violet and red-orange regions, indicating defect-related radiative transitions induced by Zn incorporation. The ability of the nanostructures to generate reactive oxygen species was evaluated indirectly using methylene blue and anthracene as chemical probes, confirming the formation of hydroxyl radicals and singlet oxygen under light irradiation. The antibacterial photody namic performance of the Zn-doped β-Ag2WO4 nanoparticles was investigated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) under white LED illumination. The results demonstrated a significant photodynamic inactivation effect against Gram-negative bacteria, which is attributed to the positive surface charge of the nanoparticles and enhanced electrostatic interaction with bacterial cell membranes. These findings suggest that Zn-doped β-Ag2WO4 nanostructures can serve as effective inorganic photosensitizers for antibacterial photodynamic applications, particularly in surface disin fection and antimicrobial treatments under visible light