Rheumatoid arthritis (RA) is an extremely common inflammatory disease that can lead to joint destruction and irreversible damage. Establishing a reliable and simple analytical method is essential for the early assessment of RA. Hypochlorous acid (HClO) serves as a biomarker, and patients with inflammatory diseases often have abnormal levels of HClO. A novel mitochondria-targeted fluorescent probe ((E)-2-(2-(6-((dimethylcarbamothioyl)oxy)naphthalen-2-yl)vinyl)-1-ethyl-3,3-dimethyl-3H-indol-1-ium, Hcy-HClO) has been designed with the purpose of monitoring HClO level fluctuations in biological systems. In the presence of HOCl, intramolecular charge transfer fluorescence is triggered, and the probe exhibits a clear change in the fluorescence signal under simulated physiological conditions. The probe features a fast response (5 s), high selectivity and sensitivity, and a lower detection limit towards HOCl. In addition, the probe exhibits great biocompatibility and low cytotoxicity. More importantly, the probe can effectively aggregate mitochondria and be applied to the imaging of intracellular HClO. It is possible that the developed probe is able to act as a powerful tool to diagnose and monitor various inflammatory diseases, including RA.

中文翻译：

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用于可视化检测活细胞中次氯酸盐的线粒体靶向荧光探针

类风湿性关节炎 (RA) 是一种极为常见的炎症性疾病，可导致关节破坏和不可逆转的损伤。建立可靠且简单的分析方法对于早期评估 RA 至关重要。次氯酸 (HClO) 作为生物标志物，炎症性疾病患者的 HClO 水平通常异常。一种新型线粒体靶向荧光探针 ((E)-2-(2-(6-((dimethylcarbamothioyl)oxy)naphthalen-2-yl)vinyl)-1-ethyl-3,3-dimethyl-3H-indol-1 -ium, Hcy-HClO) 的设计目的是监测生物系统中 HClO 水平的波动。在 HOCl 存在下，触发分子内电荷转移荧光，探针在模拟生理条件下显示出荧光信号的明显变化。探头具有快速响应（5 秒），高选择性和灵敏度，以及对 HOCl 的较低检测限。此外，该探针表现出良好的生物相容性和低细胞毒性。更重要的是，该探针可以有效地聚集线粒体并应用于细胞内 HClO 的成像。开发的探针有可能成为诊断和监测包括 RA 在内的各种炎性疾病的强大工具。