Precise Molecular Engineering of Type I Photosensitizers with Near-Infrared Aggregation-Induced Emission for Image-Guided Photodynamic Killing of Multidrug-Resistant Bacteria

Abstract

Multidrug resistance (MDR) bacteria pose a serious threat to human health. The development of alternative treatment modalities and therapeutic agents for treating MDR bacteria-caused infections remains a global challenge. Herein, a series of near-infrared (NIR) anion–π+ photosensitizers featuring aggregation-induced emission (AIE-PSs) are rationally designed and successfully developed for broad-spectrum MDR bacteria eradication. Due to the strong intramolecular charge transfer (ICT) and enhanced highly efficient intersystem crossing (ISC), these electron-rich anion–π+ AIE-PSs show boosted type I reactive oxygen species (ROS) generation capability involving hydroxyl radicals and superoxide anion radicals, and up to 99% photodynamic killing efficacy is achieved for both Methicillin-resistant Staphylococcus aureus (MRSA) and multidrug resistant Escherichia coli (MDR E. coli) under a low dose white light irradiation (16 mW cm−2). In vivo experiments confirm that one of these AIE-PSs exhibit excellent therapeutic performance in curing MRSA or MDR E. coli-infected wounds with negligible side-effects. The study would thus provide useful guidance for the rational design of high-performance type I AIE-PSs to overcome antibiotic resistance.