Organic Nanomaterials\nBased on Aza-Boron Dipyrromethene\nwith Aggregation-Induced Emission for NIR-II Fluorescence Imaging-Guided\nPhotothermal Therapy

Advancing stable and biocompatible photothermal agents\nhas emerged\nas a pivotal focus in the field of tumor photothermal treatment. Here,\nwe synthesized two aza-boron-dipyrromethene (Aza-BODIPY) derivatives\n(NN-BP and TP-BP) with donor–acceptor–donor (D-A-D)\nstructures, which exhibited robust near-infrared (NIR) absorption.\nFollowing encapsulation within the amphiphilic polymer (DSPEG-PEG<sub>2000</sub>), both NN-BP and TP-BP underwent self-assembly into nanoparticles\n(NN-BP NPs and TP-BP NPs), which displayed emission extended to near-infrared\nII regions (1000 nm). In vitro studies revealed that the two nanoparticles\nshowed outstanding biocompatibility and a strong photothermal effect.\nThese properties allowed the NPs to successfully destroy tumor cells\nunder laser exposure. The TP-BP molecules featured typical AIE structure\ncharacteristics because of the triphenylamine group on both sides.\nAfter administration of TP-BP NP through the tail vein, NIR-II fluorescence\nimaging was realized in vivo with 4T1 tumor-bearing mice as a model.\nCompared with other treatment groups, the combination of TP-BP NPs\nand laser irradiation exhibited high tumor suppression efficiency\nwithout observable side effects. Altogether, TP-BP NPs achieved promising\nNIR-II imaging and local photothermal treatment of tumors, which opened\nan avenue for the development of phototheranostics.