A simple coumarin-based fluorescent probe for specific detection of cysteine over homocysteine and glutathione

In this work, we designed and synthesized 3-cyano-2-oxo-2H-chromen-7-yl acrylate as a simple and effective probe 1, which is capable of detecting cysteine (Cys) over other biothiols, such as homocysteine and glutathione. Remarkably, with the addition of cysteine, the 125-fold increase in fluorescence intensity of probe 1 was observed at 450 nm with excitation at 413 nm and 5 min incubation time. Furthermore, it is more important that probe 1 possesses the detection limit of 80 nM, and there is good linear relationship between fluorescence intensity and concentration of Cys from 0 to 100 μM. Thus, these made a powerful safeguard for the detection of Cys in the biological system. Simultaneously, probe 1 showed low toxicity and could be used in living cell imaging.