Ternary zinc-tin-oxide nanoparticles modified by magnesium ions as a visible-light-active photocatalyst with highly strong antibacterial activity

Hospital-acquired infections (HAIs), especially nosocomial infections caused by antibiotic-resistant bacteria, are one of the most pressing health problems in all societies. Therefore, there is an urgent need to develop novel disinfection methods as alternatives to antibiotics to act against multidrug-resistant bacterial strains. Even though the photocatalytic disinfection phenomenon has been considered as a viable alternative compared to other proposed solutions, there is still a need to develop innovative functional materials for improving its efficacy under visible light to have a comparable impact to UV radiation. To boost the antibacterial efficacy under visible light, herein, we developed hydrothermally ternary zinc-tin-oxide (Zn2SnO4) nanoparticles modified with magnesium (Mg2+) ions at different doping ratios (0.5%, 1.0%, 1.5%, and 2.0%) as a photocatalytic disinfection agent and utilized it for the first time to kill Gram-negative (E. coli) and Gram-positive (S. aureus) pathogens that cause nosocomial infections. Moreover, we also explored how these materials interact with organic pollutants in the presence of visible light. Mg2+ cationic ions significantly enhanced the photocatalytic efficiency of ZTO nanoparticles under visible light to achieve 98% degradation of RhB dye in just 100 min, and rapidly produced numerous hydroxyl radicals as the main reactive oxygen species (ROS) responsible for the degradation, playing a key role in the nanoparticles impressive disinfection efficacy against these pathogenic bacteria. More importantly, Mg1.5@ZTO nanoparticles could effectively kill 99.76% of E. coli and 96.96% of S. aureus within only 1 h under visible light due to their smaller particle size, larger surface area, low recombination rate and greater ROS generation with oxygen vacancies. This research suggests that Mg-doped ZTO nanoparticles might be a viable and highly effective photocatalytic antibacterial agent candidate for future commercialization in healthcare and environmental applications.