Colorectal cancer (CRC) is one of the major causes of cancer-related mortality worldwide. Most near-infrared (NIR) agents used in clinical CRC treatment are at NIR-I (700–900 nm) window, which has limitations on deep tissue, and fluorescent probes in the second NIR (1,000–1,700 nm) allow high-resolution bioimaging with deep tissue penetration. However, existing NIR-II fluorophores used in clinical are still rare. Herein, based on shielding-donor-acceptor-donor-shielding (S-D-A-D-S) scaffold, we developed an organic small-molecule fluorophore IR-BTGP with NIR-II emission for imaging-guided photothermal therapy (PTT) in CRC mice model. Amphiphilic IR-BTGP can be self-assembled into spherical nano-micelles, which presents reliable water solubility and photothermal conversion efficiency (30.2%). In vitro experiments indicate that cancer cells treated with IR-BTGP were significantly killed upon 808 nm light irradiation. Furthermore, in vivo NIR-II fluorescence imaging confirms that IR-BTGP accumulates in the tumor region. Remarkably, a significant tumor inhibition rate (78.5%) was observed in tumor-bearing mice when treated with IR-BTGP plus 808 nm irradiation. Therefore, this work shows that IR-BTGP holds great promise as an NIR-II fluorescence imaging-guided PTT platform for CRC in the future.

结直肠癌（CRC）是全球癌症相关死亡的主要原因之一。临床 CRC 治疗中使用的大多数近红外 (NIR) 试剂均处于 NIR-I (700–900 nm) 窗口，该窗口对深层组织有限制，而第二个 NIR (1,000–1,700 nm) 中的荧光探针可实现高分辨率具有深层组织穿透力的生物成像。然而，现有应用于临床的NIR-II荧光团还很少。在此，基于屏蔽-供体-受体-供体-屏蔽（S-D-A-D-S）支架，我们开发了一种具有NIR-II发射功能的有机小分子荧光团IR-BTGP，用于CRC小鼠模型中的成像引导光热治疗（PTT）。两亲性IR-BTGP可以自组装成球形纳米胶束，具有可靠的水溶性和光热转换效率（30.2%）。体外实验表明，经过 IR-BTGP 处理的癌细胞在 808 nm 光照射下被显着杀死。此外，体内 NIR-II 荧光成像证实 IR-BTGP 在肿瘤区域积聚。值得注意的是，当用 IR-BTGP 加 808 nm 照射治疗时，在荷瘤小鼠中观察到显着的肿瘤抑制率 (78.5%)。因此，这项工作表明 IR-BTGP 作为未来 NIR-II 荧光成像引导的 CRC PTT 平台具有广阔的前景。