Ulcerative colitis (UC) is an inflammatory disease that leads to the overexpression of peroxynitrite (ONOO^–). Up to now, it has been a challenge to design a colon-targeted fluorescent probe with a large emission shift that can detect and image ONOO^– in UC mice. Here, a fluorophore (pyran-coumarin) is linked with cholic acid to develop a colon-targeted fluorescent probe (CPC) for the detection of ONOO^–. The fluorescent probe showed strong near-infrared emission at 725 nm. After reacting with ONOO^–, it can be observed that the fluorescence intensity at 725 nm decreases obviously, and the signal at 490 nm increases clearly with an obvious emission shift (235 nm). This response mechanism causes the probe to have good sensitivity and selectivity. Additionally, the probe CPC shows good targeting ability for the cells with overexpressingTGR5 receptors and displays good results for detecting exogenous and endogenous ONOO^– in the cells. More importantly, the probe CPC can be especially assembled in the colon site to distinguish normal and UC mice and provide significant information for the diagnosis of UC.

中文翻译：

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一种新型结肠靶向比率探针，具有大发射偏移，用于溃疡性结肠炎中过氧亚硝酸盐成像


溃疡性结肠炎 （UC） 是一种导致过氧亚硝酸盐 （^ONOO–） 过表达的炎症性疾病。到目前为止，设计一种具有大发射偏移的结肠靶向荧光探针，可以检测和成像 UC 小鼠中的 ONOO^– 一直是一个挑战。在这里，荧光团 （吡喃香豆素） 与胆酸连接，形成用于检测 ONOO 的结肠靶向荧光探针 （CPC^{） –}。荧光探针在 725 nm 处显示出较强的近红外发射。与 ONOO^– 反应后，可以观察到 725 nm 处的荧光强度明显降低，490 nm 处的信号明显增加，发射偏移明显 （235 nm）。这种响应机制使探针具有良好的灵敏度和选择性。此外，探针 CPC 对过表达 TGR5 受体的细胞显示出良好的靶向能力，并且在检测细胞中的外源性和内源性 ONOO^– 方面显示出良好的结果。更重要的是，探针 CPC 可以特别组装在结肠部位，以区分正常小鼠和 UC 小鼠，并为 UC 的诊断提供重要信息。