Ulcerative colitis is a prevalent inflammatory disease caused by the intestinal bacterial infection. And it is related to the hypoxic degrees in the colon microenvironment. Hypoxia, a condition of imbalance in O₂ supply and consumption, is accompanied by the overexpressed level of nitroreductase (NTR). Therefore, the NTR detection has been widely applied for the diagnosis of hypoxia-related diseases. In this study, we developed a novel near-infrared fluorescent probe (IW-1) for NTR. Upon reaction with NTR, IW-1 exhibited a significant fluorescence off-on response at 740 nm with a low detection limit of 0.043 μg/mL. Confocal fluorescence imaging verified its ability to detect the overexpression of NTR in cancer cells. More significantly, IW-1 was applied for in vivo hypoxia imaging in tumors and dextran sulphate sodium (DSS)-induced ulcerative colitis mouse model. We expect that the probe may present a new tool for better understanding the biological functions of NTR as well as revealing essential information about hypoxia-related pathological processes, including cancer and ulcerative colitis.

溃疡性结肠炎是一种由肠道细菌感染引起的常见炎症性疾病。并且与结肠微环境的缺氧程度有关。_{缺氧是一种 O 2}供应和消耗失衡的情况，伴随着硝基还原酶 (NTR) 的过表达水平。因此，NTR检测已广泛应用于缺氧相关疾病的诊断。在这项研究中，我们开发了一种用于 NTR的新型近红外荧光探针 ( IW-1 )。与 NTR 反应后，IW-1在 740 nm 处表现出显着的荧光关断响应，检测限低至 0.043 μg/mL。共聚焦荧光成像验证了其检测癌细胞中 NTR 过表达的能力。更重要的是，IW-1应用于肿瘤和葡聚糖硫酸钠（DSS）诱导的溃疡性结肠炎小鼠模型中的体内缺氧成像。我们预计该探针可能会提供一种新工具，以更好地了解 NTR 的生物学功能，并揭示与缺氧相关的病理过程（包括癌症和溃疡性结肠炎）的基本信息。