Laser-Prepared ZnO-Ag Nanoparticles with High Light-Enhanced Antibacterial Activity

Recently, the urgency of combating antibiotic-resistant bacteria, viruses, and other pathogens has dramatically increased. With the development of nanotechnology, significant hopes are placed on nanoparticles with antimicrobial properties. The efficiency of such materials can be significantly enhanced through light-activated processes. In this study, we prepared composite ZnO-Ag nanoparticles and tested their ability to inhibit <i>Staphylococcus aureus</i> bacteria. The composite ZnO-Ag nanoparticles were fabricated using pulsed laser ablation of Zn and Ag targets in water using a nanosecond pulsed laser. During antibacterial tests, light-enhanced activation of the nanoparticles was achieved using low-power near UV (375 nm) and blue visible (410 nm) LED irradiation. For comparison, similar laser-fabricated ZnO nanoparticles were also tested. The combined use of nanoparticles and LED irradiation significantly increased the generation of reactive oxygen species. As a result, low nanoparticle concentrations (0.05 g/L) and low-power LED irradiation (0.17-0.22 W) significantly reduced the concentration of <i>Staphylococcus aureus</i> bacteria, including experiments with visible light irradiation. Compared to their ZnO counterparts, the use of ZnO-Ag composite particles led to an additional increase in antimicrobial activity.