Lysosome‐Targeted Aggregation‐Induced Emission Photosensitizer with Donor–Acceptor Structure for Imaging and Enhanced Photodynamic Therapy

The development of photosensitizers (PSs) with extended triplet‐state lifetimes, efficient reactive oxygen species (ROS) generation, organelle‐specific targeting, good water solubility, and high photostability, is essential for advancing photodynamic therapy (PDT). Although molecular aggregation holds promise for designing organic nano‐PSs with enhanced therapeutic effects, controlling dye aggregation remains a significant challenge. In this study, we present a simple yet robust synthetic strategy for developing heavy‐atom‐free PSs with intramolecular charge transfer (ICT)‐coupled aggregation‐induced emission (AIE) properties. These PSs feature donor–acceptor (D–A) structures, namely Lyso‐Naphth‐AIE and Butyl‐Naphth‐AIE, which exhibit high photostability and negligible dark toxicity. Upon light irradiation, these AIE systems efficiently generate ROS via both Type I and II mechanisms. By incorporating p‐methoxytriphenylamine (MeO‐TPA) as a rotor unit, we enhanced AIE and promoted twisted intramolecular charge transfer (TICT), resulting in improved near‐infrared luminescence in the aggregated state. Notably, the Lyso‐Naphth‐AIE nano‐PSs demonstrated effective lysosome‐targeting and light‐triggered intracellular ROS production, leading to apoptosis, in cancer cells. This work establishes a new approach for designing multifunctional AIE PSs that enable imaging‐guided PDT.