Efficient type Ⅰ and type Ⅱ ROS generated aggregation-induced emission photosensitizer for mitochondria targeted photodynamic therapy

Fluorescence imaging-guided photodynamic therapy (PDT) is considered as an ideal alternative strategy to treat tumors. However, insufficient supply of oxygen in solid tumor tissue, aggregation-caused quenching (ACQ) of photosensitizers (PSs), poor targeting-specificity of cancer cells and short wavelengths of emission are representative obstacles for effective PDT. In this paper, three D-π-A structured PSs TSB-OH, TSBPy-OH, TSBPy-DNT with aggregation induced emission (AIE) properties and integrated type I and type II ROS generation were synthesized by modulating distinct acceptor units. Among them, TSBPy-OH is optimal with multiple advantages including near-infrared emission, good biocompatibility, remarkably intracellular ROS production ability, mitochondria targeting capability inducing cell apoptosis and enhancing PDT, and long-term tumor retention ability for imaging-guided photodynamic therapy. More importantly, efficient in vitro cancer cells damage, in vivo tumor ablation and ignorable damage in major organs during PDT are demonstrated, suggesting potential capability of TSBPy-OH in safe and effective fluorescence imaging-guided PDT. This successful example of AIE theranostics design would provide a reference for the modification of D-π-A structure organic AIEgens.