The combination of S-doped ZIF-8 with graphene oxide for enhanced near-infrared light photocatalytic and photothermal sterilization

The problem of bacterial resistance caused by the overuse of antibiotics was a constant threat to human health. Photocatalytic therapy was an important tool to address this problem but was limited by its photocatalytic properties and biocompatibility. Herein ZIF-8 was doped by sulfur (S) and then combined with graphene oxide (GO) to form a heterojunction (S-ZIF-8/GO). The photocatalytic performance of the composite was significantly enhanced compared to that of the single component. The underlying mechanism is as following factors. On the one hand, S doping induced the formation of the Zn-S bond in ZIF-8, thus improving NIR light absorption and the yields of photogenerated electron-hole pairs. On the other hand, the interface between S-ZIF-8 and GO accelerated the transfer of photogenerated electrons from S-ZIF-8 to GO. In addition, the S-ZIF-8/GO has even better photothermal performance. Further experiments revealed the bacteria-killing mechanism of S-ZIF-8/GO, i.e., the bacterial cell membrane was destroyed with increased permeability by hyperthermia caused by the photothermal effect, allowing the leakage of inside protein and the entrance of ROS into the bacteria to destroy the inside substances. In vivo animal tests showed that the composite was beneficial for wound healing due to the slow release of Zn2+ ions from S-ZIF-8/GO.