Gallium Oxide Nanoparticles With Controllable Morphologies as Effective Photocatalytic Antimicrobial Agents

Antibiotic abuse has led to the emergence of drug-resistant bacteria, which have become the leading cause of death worldwide. Therefore, the search for effective antimicrobial reagents has become particularly important. In this study, gallium oxide nanoparticles (Ga₂O₃ NPs) with controllable morphologies were successfully synthesized using a high-temperature thermal decomposition method. The synthesized Ga₂O₃ NPs with different modifications exhibited good biocompatibility and photocatalytic antimicrobial activity. Notably, small-sized spherical Ga₂O₃ NPs exhibited the best photocatalytic antibacterial properties, achieving over 99% bacterial inhibition at a 200 μg/mL concentration. Moreover, the antimicrobial mechanism of Ga₂O₃ nanoparticles has been systematically studied. Ga₂O₃ nanoparticles with a positive charge have strong absorption with bacteria, and they can impede biofilm formation, disrupt the bacterial cell membrane, induce nucleic acid leakage, and provoke an elevation in reactive oxygen species (ROS) under a xenon lamp light. The antibacterial process was related to protein binding, RNA degradation, and biofilm formation pathways. Ga₂O₃ NPs combined with PCAT were first used as an effective antibacterial method, overcoming the low catalytic efficiency of traditional photocatalysts under visible light and demonstrating broader application potential, which will provide an essential reference for developing novel photocatalytic antimicrobial agents.