The rapid photoresponsive bacteria-killing of Cu-doped MoS₂

Bacterial infection is a serious public health issue because this may cause bacterial pneumonia and bacteria-infected sepsis. The conventional antibiotic therapy can cause bacterial resistance and other adverse effects. Herein, we designed a novel photoresponsive hybrid, in which MoS₂ nanosheets were doped with copper ions (MoS₂@Cu²⁺). This system can effectively kill bacteria under 660 nm visible light irradiation due to enhanced photocatalytic and photothermal performances. The underlying mechanism is that when doping copper ions in MoS₂, the photogenerated electrons can be rapidly transferred from the conduction band of MoS₂ to copper ions, consequently reducing the electron-hole recombination, thereby enhancing the yield of radical oxygen species (ROS). Besides the intrinsic photothermal performance of MoS₂, the Cu²⁺ ion can absorb photons and transfer the photoenergy into heat due to the d-d transition of electrons, resulting in enhanced photothermal properties of MoS₂@Cu²⁺ compared with pristine MoS₂. Therefore, owing to the synergistic action of hyperthermia, ROS and released Cu²⁺, this system exhibited highly effective antibacterial efficacy when exposed to 660 nm light for 20 min, i.e., 99.64% against Staphylococcus aureus. The cytotoxicity test showed that the synthesized MoS₂@Cu²⁺ had good biocompatibility. This system will be a potential platform for environmental disinfection, healing of bacteria-infected wounds and other rapid bacteria-killing fields.