A simple strategy for the efficient design of mitochondria-targeting NIR-II phototheranostics.

The pursuit of phototheranostic agents with near-infrared II (NIR-II) emission, high photothermal conversion efficiency (PCE) and the robust generation of reactive oxygen species (ROS) in the aggregated state is always in high demand but remains a big challenge. Herein, we report a simple strategy to endow molecules with NIR-II imaging and photothermal therapy (PTT)/photodynamic therapy (PDT) abilities by equipping NIR-II aggregation-induced emission luminogens (AIEgens) with the cationic trimethylammonium unit, named as TDTN. The resultant TDTN species can self-assemble into nanoparticles, which exhibit a maximum emission at ∼1052 nm, a high PCE (66.7%), type I and type II ROS generation and a mitochondria-targeting ability, simultaneously. The TDTN can realize brain imaging with bright fluorescence and an effective tumor killing effect. Overall, this work presents an innovative design strategy to develop multimodality phototheranostic agents.