Self-assembled NIR-II Fluorophores with Ultralong Blood Circulation for Cancer Imaging and Image-guided Surgery

Yang Li, Jianfeng Gao, Shuping Wang, Mingxia Du, Xiaowen Hou, Tian Tian, Xue Qiao, Zhiquan Tian, Peter J. Stang*, Shijun Li*, Xuechuan Hong*, and Yuling Xiao*

Journal of Medicinal Chemistry 2022, 65, 3, 2078–2090

https://pubs.acs.org/doi/10.1021/acs.jmedchem.1c01615

Abstract

Complete excision of the last remaining 1–2% of tumor tissue without collateral damage remains particularly challenging. Herein, we report thiophenthiadiazole (TTD)-derived fluorophores L6-PEGnk (n = 1, 2, 5) as new-generation NIR-II (1000–1700 nm) probes with exceptional nonfouling performance and significantly high fluorescence quantum yields in water. L6-PEG2k can self-assemble into vesicular micelles and exhibited minimal immunogenicity, low binding affinities, ultralong blood circulation (t1/2 = 59.5 h), and a supercontrast ratio in vivo. Most importantly, L6-PEG2k achieved excellent in vivo CT-26 and U87MG tumor targeting and accumulation (>20 d) through intraperitoneal or intravenous injection. A subcutaneous U87MG tumor and orthotopic brain glioma were successfully resected under NIR-II FIGS in our animal model via intraperitoneal injection in an extended time window (48–144 h). This study highlights the potential of using L6-PEG2K as self-assembling molecular probes with long-circulation persistence for routine preoperative tumor assessment and precise intraoperative image-guided resection.