Although many types of second near-infrared (NIR-II) dyes have been developed, the NIR-II dye bearing a single reactive group, which is indispensable for specifically labeling nanomaterials or biofunctional molecules, is still lacking. In this work, a donor–acceptor–donor type NIR-II dye named IR1032 bearing an amino group was synthesized and used to covalently label cylindrical polymer brushes. The labeled polymer brushes (named brushes1032) had densely grafted poly(ethylene glycol) (PEG) chains and exhibited a wormlike morphology. In aqueous medium, brushes1032 had an emission peak at 1032 nm and a quantum yield (QY) of ∼0.13% measured with IR 26 as a reference (QY = 0.05%). We demonstrated that the dense PEG chains in brushes1032 were greatly favorable for their QY by separating the fluorophores and shielding them from the interactions with water. After being injected intravenously into tumor-bearing mice, brushes1032 showed high tumor accumulation and provided high-resolution fluorescence imaging, exhibiting great application potentials in tumor detection.

中文翻译：

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用于体内成像的 NIR-II 染料标记圆柱形聚合物刷

尽管已经开发了许多类型的第二近红外（NIR-II）染料，但是对于特异性标记纳米材料或生物功能分子必不可少的带有单个反应基团的NIR-II染料仍然缺乏。在这项工作中，合成了一种名为 IR1032 的带有氨基的供体-受体-供体型 NIR-II 染料，并用于共价标记圆柱形聚合物刷。标记的聚合物刷（名为brushes1032）具有密集接枝的聚（乙二醇）（PEG）链并表现出蠕虫状形态。在水性介质中，brushes1032 在 1032 nm 处具有发射峰，以 IR 26 作为参考（QY = 0.05%）测量的量子产率 (QY) 约为 0.13%。我们通过分离荧光团并屏蔽它们与水的相互作用，证明了画笔 1032 中密集的 PEG 链对其 QY 非常有利。经静脉注射到荷瘤小鼠体内后，brushes1032 显示出高肿瘤积累并提供高分辨率荧光成像，在肿瘤检测中显示出巨大的应用潜力。