Making the Best Use of Excited-State Energy: Multimodality Theranostic Systems Based on Second Near-Infrared (NIR-II) Aggregation-Induced Emission Luminogens (AIEgens)

A single-component multimodal theranostic platform that takes advantage of multiple imaging and therapy techniques may offer improved diagnostic monitoring capabilities and therapeutic efficacies. In this study, through structural tuning, a novel theranostic agent (TSSAM) with aggregation-induced emission (AIE) characteristics, bright second near-infrared (NIR-II) emission, high reactive oxygen species (ROS) generation capability, and excellent photothermal conversion efficiency (40.1%) was developed. TSSAM makes the best use of its excited-state energy and keeps perfect equilibrium between radiative and nonradiative transition to satisfy the needs of both NIR-II fluorescence imaging (FLI)/photoacoustic imaging (PAI)/photothermal imaging (PTI) trimodal imaging and photodynamic therapy (PDT)/photothermal therapy (PTT) synergistic therapy. Further experiments validated the superior imaging quality and tumoricidal activity of TSSAM, in which tumor tissues were completely eradicated and tumor metastasis was effectively inhibited by merely single injection and one-time laser irradiation. Therefore, this research presents a smart multifunctional material holding great promise in both basic research and clinical practice.