Thiophene π‐Bridge Manipulation of NIR‐II AIEgens for Multimodal Tumor Phototheranostics

Abstract The fabrication of a multimodal phototheranostic platform on the basis of single‐component theranostic agent to afford both imaging and therapy simultaneously, is attractive yet full of challenges. The emergence of aggregation‐induced emission luminogens (AIEgens), particularly those emit fluorescence in the second near‐infrared window (NIR‐II), provides a powerful tool for cancer treatment by virtue of adjustable pathway for radiative/non‐radiative energy consumption, deeper penetration depth and aggregation‐enhanced theranostic performance. Although bulky thiophene π‐bridges such as ortho ‐alkylated thiophene, 3,4‐ethoxylene dioxythiophene and benzo[ c ]thiophene are commonly adopted to construct NIR‐II AIEgens, the subtle differentiation on their theranostic behaviours has yet to be comprehensively investigated. In this work, systematical investigations discovered that AIEgen BT‐NS bearing benzo[ c ]thiophene possesses acceptable NIR‐II fluorescence emission intensity, efficient reactive oxygen species generation, and high photothermal conversion efficiency. Eventually, by using of BT‐NS nanoparticles, unprecedented performance on NIR‐II fluorescence/photoacoustic/photothermal imaging‐guided synergistic photodynamic/photothermal elimination of tumors was demonstrated. This study thus offers useful insights into developing versatile phototheranostic systems for clinical trials.