Recent molecular design strategies for efficient photodynamic therapy and its synergistic therapy based on AIE photosensitizers

Cancer seriously endangers human life and health. Recently, the development of AIEgens with aggregation-induced emission (AIE) effect as a new generation of photosensitizers (PSs) to circumvent aggregation-induced fluorescence quenching and reduction of ROS generation has received extensive attention in photodynamic therapy (PDT), a non-invasive anticancer therapy. Rational molecular design can enhance the photosensitization of AIE PSs to achieve effective PDT and can realize the construction of functionalized AIE PSs and synergistic therapy based on AIE PSs. To improve the efficacy of AIE PSs for cancer treatment, many groups have conducted molecular design studies and produced exciting results. This review summarizes the molecular design strategies of three types of AIE PSs for effective photodynamic therapy, focusing on the design strategies of pure organic small molecule type AIE PSs, and reviews the existing design strategies of metal complexes and conjugated polymers. Subsequently, the design strategy to achieve synergistic treatment of AIE PSs from molecular modifications is summarized. The challenges and prospects of the AIE PSs research field are further discussed.