A novel fluorescent probe with a large stokes shift for cysteine based on dicyanoisophorone

In this work, a dicyanoisophorone-based turn-on fluorescent probe, DCIP, for highly selective and sensitive detection of cysteine was designed based on nucleophilic substitution mechanism. Moreover, compared with typical cysteine probes, DCIP showed great selectivity and sensitivity for cysteine over other amino acids including the similar structured homocysteine (Hcy) and glutathione (GSH). Further, the detection limit toward cysteine was calculated to be as low as 0.70?μM. In addition, the utility of DCIP as a bioanalytical molecular tool was demonstrated by fluorescence imaging of biothiols in living cells.