Antibacterial Activity of Radiosensitizer Bismuth Nanomaterials

Antimicrobial resistance presents a growing global threat, necessitating the development of therapeutic approaches. Traditional antibiotics often act on a single molecular target, making them susceptible to the development of resistance. In contrast, metal-based nanomaterials exhibit multifactorial antibacterial mechanisms, offering a promising alternative. This study integrates the antibacterial and radiosensitizing properties of bismuth-based nanomaterials, specifically, bismuth vanadate (BiVO₄) and bismuth tungstate (Bi₂WO₆), to demonstrate the radiocatalytic antibacterial activity. We synthesized BiVO₄ and Bi₂WO₆ nanomaterials via hydrothermal methods and characterized their morphology, crystallinity, and electronic structure using electron microscopy, photoluminescence, and X-ray absorption spectroscopy (XAS and XANES). These materials exhibited robust generation of reactive oxygen species (ROS) upon exposure to low-dose X-ray radiation (0.042 Gy/min; 50 kV, 0.3 mA), resulting in significant bacterial inactivation of <i>Escherichia coli</i><i>,</i> <i>Pseudomonas aeruginosa</i>, and <i>Staphylococcus aureus</i> at doses ranging from 0.42 to 3.36 Gy. Radiocatalytic efficacy was confirmed using a ROS-sensitive knockout <i>E. coli</i> strain (Δ<i>oxyR</i>), underscoring that ROS are the primary bactericidal agents. The findings demonstrate that these nanomaterials enhance radiation dose deposition due to their high atomic number and bandgap-tuned ROS generation. This platform could potentially be used for diverse applications, such as biofilm eradication in industrial pipelines, metal surface sterilization in marine environments, and space-based microbial decontamination.