Cysteine (Cys) is an important endogenous amino acid and plays critical physiological roles in living systems. Herein, an endoplasmic reticulum (ER)-targeting fluorescent probe (FER-Cys) was designed and prepared for imaging of Cys in living cells. The probe FER-Cys consists of a fluorescein framework as the fluorescent platform, acrylate group as the response site for the selective recognition of Cys, and ER-specific p-toluenesulfonamide fragment. After the response of probe FER-Cys to Cys, a turn-on fluorescence signal at 546 nm could be detected obviously. The probe FER-Cys further shows desirable selectivity to Cys. Finally, the probe FER-Cys was proven to selectively detect Cys in live cells and successfully image the changes of Cys level in the cell models of H₂O₂-induced redox imbalance.

半胱氨酸（Cys）是重要的内源氨基酸，在生命系统中起着至关重要的生理作用。在此，设计并准备了靶向内质网（ER）的荧光探针（FER-Cys）以对活细胞中的Cys成像。探针FER-Cys由荧光素框架作为荧光平台，丙烯酸酯基作为选择性识别Cys的反应位点和ER特异性对甲苯磺酰胺片段组成。探针FER-Cys对Cys响应后，可以明显检测到546 nm处的开启荧光信号。探针FER-Cys进一步显示出对Cys的理想选择性。最后，探针FER-Cys被证明可以选择性地检测活细胞中的Cys，并成功地在H ₂ O ₂引起的氧化还原失衡的细胞模型中成像Cys水平的变化。