放射線増感剤ビスマスナノマテリアルの抗菌活性

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 Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus at doses ranging from 0.42 to 3.36 Gy. Radiocatalytic efficacy was confirmed using a ROS-sensitive knockout E. coli strain (ΔoxyR), 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.