Near-Infrared II Agent with Excellent Overall Performance for Imaging-Guided Photothermal Thrombolysis

Near-infrared II (NIR-II) imaging and photothermal therapy hold tremendous potential in precision diagnosis and treatment within biological organisms. However, a significant challenge is the shortage of NIR-II fluorescent probes with both high photothermal conversion coefficient (PCE) and fluorescence quantum yield (Φ_F). Herein, we address this issue by integrating a large conjugated electron-withdrawing core, multiple rotors, and multiple alkyl chains into a molecule to successfully generate a NIR-II agent 4THTPB with excellent PCE (87.6%) and high Φ_F (3.2%). 4THTPB shows a maximum emission peak at 1058 nm, and the emission tail could extend to as long as 1700 nm. These characteristics make its nanoparticles (NPs) perform well in NIR-II high-resolution angiography, thereby allowing for precise diagnosis of thrombus through NIR-II imaging and enabling efficient photothermal thrombolysis. This work not only furnishes a NIR-II agent with excellent overall performance but also provides valuable guidance for the design of high-performance NIR-II agents.