A Stable Open-Shell Conjugated Diradical Polymer with Ultra-High Photothermal Conversion Efficiency for NIR-Ⅱ Photo-Immunotherapy of Metastatic Tumor

作者：Yijian Gao; Ying Liu; Xiliang Li; Hui Wang; Yuliang Yang; Yu Luo; Yingpeng Wan; Chun-sing Lee; Shengliang Li; Xiao-Hong Zhang

来源：Nano-Micro Letters, 2024, 16(2): 1-14.

DOI：10.1007/s40820-023-01219-x

• NIR-Ⅱ conjugated polymer
• Photothermal
• Radical
• Nanoparticles
• Cancer therapy

Massive efforts have been concentrated on the advance of emi-nent near-infrared(NIR)photothermal materials(PTMs)in the NIR-Ⅱ window(1000-1700 nm),especially organic PTMs because of their intrinsic biological safety compared with inorganic PTMs.However,so far,only a few NIR-Ⅱ-responsive organic PTMs was explored,and their photothermal conversion effi-ciencies(PCEs)still remain relatively low.Herein,donor-acceptor conjugated diradical polymers with open-shell characteristics are explored for synergisti-cally photothermal immunotherapy of metastatic tumors in the NIR-Ⅱ By employing side-chain regulation,the conjugated diradical polymer TTB-2 with obvious NIR-Ⅱ absorption was developed,and its nanoparticles realize a record-breaking PCE of 87.7％upon NIR-Ⅱ light illustration.In vitro and in vivo experiments demonstrate that TTB-2 nanoparticles show good tumor photoablation with navigation of photoacoustic imaging in the NIR-Ⅱ win-dow,without any side-effect.Moreover,by combining with PD-1 antibody,the pulmonary metastasis of breast cancer is high-effectively prevented by the efficient photo-immunity effect.Thus,this study explores superior PTMs for cancer metastasis theranostics in the NIR-Ⅱ window,offering a new horizon in developing radical-characteristic NIR-Ⅱphotothermal materials.