Fluorescein‐derived superoxide probes featuring a copper(II) complex that can be activated by superoxide to initiate ether bond cleavage and uncage a fluorescein reporter for imaging in live cells are described. Compared to other superoxide sensing moieties, this bond cleavage strategy can be modularly adapted to fluorescent reporters with different properties without compromising the superoxide reactivity and selectivity. A green‐emitting probe and its lysosome‐targeting analogue have been successfully developed. Both probes are sensitive with more than 30‐fold fluorescence enhancement towards superoxide and are highly selective with no significant response towards other reactive oxygen species. A structure–activity relationship study of the copper‐based superoxide trigger showed that the secondary coordination environment of the copper(II) center is important for the superoxide reactivity and selectivity. The probes have been applied in imaging changes in intracellular superoxide level in live HeLa and HEK293T cells upon menadione stimulation and also in a cellular inflammation model in RAW 264.7 cells.

中文翻译：

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带有模块化铜基触发器的含荧光素超氧化物探针。

描述了具有铜（II）配合物的荧光素衍生的超氧化物探针，该铜（II）配合物可被超氧化物激活以引发醚键裂解，并解开用于​​活细胞成像的荧光素报告基因。与其他超氧化物感测部分相比，该键裂解策略可以模块化地适应具有不同特性的荧光报告分子，而不会损害超氧化物的反应性和选择性。已经成功开发了一种发射绿色光的探针及其靶向溶酶体的类似物。两种探针均对超氧化物具有30倍以上的荧光增强敏感性，并且具有高度选择性，对其他活性氧种类无明显响应。对铜基超氧化物触发器的结构-活性关系研究表明，铜（II）中心的二级配位环境对超氧化物的反应性和选择性很重要。该探针已用于对甲萘醌刺激后的活HeLa和HEK293T细胞内细胞内超氧化物水平的变化进行成像，也已应用于RAW 264.7细胞的细胞炎症模型中。