Bioactive AIEgens Tailored for Specific and Sensitive Theranostics of Gram-Positive Bacterial Infection

Diseases caused by bacterial infections are increasingly threatening human health. As a major part of the microbial family, Gram-positive bacteria induce severe infections in hospitals and communities. Therefore, developing antibacterial materials that can recognize bacteria and specifically kill them is significant to cope with fatal bacterial infection. To this end, we designed and prepared a series of positively charged photosensitizers with an aggregation-induced emission feature and a type I reactive oxygen species (ROS) generation ability. Based on a molecular engineering strategy, the PS abbreviated to MTTTPy that owns a superior ROS generation ability and red emission in aggregation is obtained by adjusting bridging groups. Due to the unique molecular structure, MTTTPy can sensitively and specifically recognize and light up Gram-positive bacteria through electrostatic adsorption and void permeability. In addition, it can kill 95% of the recognized bacteria at a low concentration of 0.5 μM by generating oxygen-independent ROS under white light irradiation. Both in vitro and in vivo studies verify the sensitive and specific recognition and killing effect of MTTTPy toward Gram-positive bacteria. This work provides superior material-integrated diagnosis and treatment for Gram-positive bacteria-caused infectious diseases and shows potential for addressing bacterial resistance.