Fluorescence imaging in the second near-infrared (NIR-II, 1000–1700 nm) region holds great promise for in vivo bioimaging. However, it is challenging to develop a brilliant donor–acceptor–donor (D–A–D) type NIR-II fluorophore with maximal absorption beyond 1000 nm in aqueous solution. Herein, we report a bright D–A–D type BOIMPY-based NIR-II dye (NK1143) with peak absorption/emission at 1005/1143 nm for in vivo bioimaging. Co-assembly of NK1143, SC12 (intermolecular steric hindrance modulator), and DSPE-PEG2000 effectively inhibits H-aggregation of NK1143 in aqueous solution and enhances the brightness simultaneously up to 53-fold by leveraging synergistic steric regulation strategy. Notably, this strategy allows for deep optical penetration of 8 mm and high-resolution blood vessels imaging in vivo, displaying high signal-to-background ratio of 7.8/1 under 980 nm excitation. More importantly, the BOIMPY-based nanoprobe can passively target and clearly visualize broad types of tumor xenografts, further improving intraoperative NIR-II fluorescence-guided resection of tiny metastases of less than 1 mm. This work provides an effective strategy for the development of BOIMPY-based NIR-II organic fluorophores with broad applications.

中文翻译：

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基于 BOIMPY 的 NIR-II 荧光团具有高亮度和超过 1000 nm 的长吸收，用于体内生物成像：协同空间调控策略

第二近红外（NIR-II，1000-1700 nm）区域的荧光成像为体内生物成像提供了广阔的前景。然而，开发在水溶液中最大吸收超过 1000 nm 的出色供体-受体-供体 (D-A-D) 型 NIR-II 荧光团具有挑战性。在这里，我们报告了一种明亮的 D-A-D 型基于 BOIMPY 的 NIR-II 染料 (NK1143)，在 1005/1143 nm 处具有峰值吸收/发射，用于体内生物成像。NK1143、SC12（分子间空间位阻调节剂）和 DSPE-PEG2000 的共组装有效地抑制了 NK1143 在水溶液中的 H 聚集，并通过利用协同空间调节策略将亮度同时提高了 53 倍。值得注意的是，该策略允许 8 mm 的深度光学穿透和体内高分辨率血管成像，显示出 7 的高信背景比。在 980 nm 激发下为 8/1。更重要的是，基于 BOIMPY 的纳米探针可以被动靶向并清晰地显示广泛类型的肿瘤异种移植物，进一步改善术中 NIR-II 荧光引导切除小于 1 mm 的微小转移灶。这项工作为开发具有广泛应用的基于 BOIMPY 的 NIR-II 有机荧光团提供了有效的策略。