Biothiols are the main antioxidants in regulating the redox balance and resisting oxidative stress in various biological processes, but the long detection time of current fluorescent probes hinders their rapid imaging in vitro and in vivo. To reveal the influx of biothiols, we rationally develop an ortho-activation approach to accelerate the reaction between the probe and biothiols, by introducing electron-withdrawing fluorine atom into the ortho-site of the phenolic hydroxyl group in the NIR probe to generate an ortho-inductive effect. The ortho-fluorine helps to increase the chemical reactivity of the molecular structure, resulting in a significantly shorter detection time (within 5 min) as compared to previous reports (> 20 min for acrylates-based probes in aqueous solution). Based on this approach, our near-infrared probe 2F-RBX can sensitively and efficiently detect endogenous biothiols in living HepG2 cells and in vivo. These data suggest that ortho-activation is a simple and flexible approach to construct sensitive fluorescent probes for rapid imaging of biothiols, and perhaps other molecules in future, under biological circumstances.

生物硫醇是多种生物过程中调节氧化还原平衡、抵抗氧化应激的主要抗氧化剂，但目前荧光探针检测时间较长，阻碍了其在体外和体内的快速成像。为了揭示生物硫醇的流入，我们合理地开发了一种邻位激活方法来加速探针和生物硫醇之间的反应，通过将吸电子氟原子引入近红外探针中酚羟基的邻位以产生邻位-感应效应。邻氟有助于增加分子结构的化学反应性，与之前的报道相比（水溶液中基于丙烯酸酯的探针> 20分钟），检测时间显着缩短（5分钟内）。基于这种方法，我们的近红外探针2F-RBX可以灵敏、高效地检测活体HepG2细胞和体内的内源性生物硫醇。这些数据表明，邻位激活是构建敏感荧光探针的简单而灵活的方法，用于在生物环境下对生物硫醇以及未来可能的其他分子进行快速成像。