High UV-Vis-NIR Light-Induced Antibacterial Activity by Heterostructured TiO(2)-FeS(2) Nanocomposites

PURPOSE: Antibiotic resistance issues associated with microbial pathogenesis are considered to be one of the most serious current threats to health. Fortunately, TiO(2), a photoactive semiconductor, was proven to have antibacterial activity and is being widely utilized. However, its use is limited to the short range of absorption wavelength. METHODS: In this work, heterostructured TiO(2)-FeS(2) nanocomposites (NCs) were successfully prepared by a facile solution approach to enhance light-induced antibacterial activity over a broader absorption range. RESULTS: In TiO(2)-FeS(2) NCs, FeS(2) NPs, as light harvesters, can effectively increase light absorption from the visible (Vis) to near-infrared (NIR). Results of light-induced antibacterial activities indicated that TiO(2)-FeS(2) NCs had better antibacterial activity than that of only TiO(2) nanoparticles (NPs) or only FeS(2) NPs. Reactive oxygen species (ROS) measurements also showed that TiO(2)-FeS(2) NCs produced the highest relative ROS levels. Unlike TiO(2) NPs, TiO(2)-FeS(2) NCs, under light irradiation with a 515-nm filter, could absorb light wavelengths longer than 515 nm to generate ROS. In the mechanistic study, we found that TiO(2) NPs in TiO(2)-FeS(2) NCs could absorb ultraviolet (UV) light to generate photoinduced electrons and holes for ROS generation, including ⋅O(2)(−) and ⋅OH; FeS(2) NPs efficiently harvested Vis to NIR light to generate photoinduced electrons, which then were transferred to TiO(2) NPs to facilitate ROS generation. CONCLUSION: TiO(2)-FeS(2) NCs with superior light-induced antibacterial activity could be a promising antibacterial agent against bacterial infections.