Novel dual-site fluorescent probe for monitoring cysteine and sulfite in living cells.

Fluorescent probes have been considered to be efficient tools for the visualization of physiological and pathological processes. Herein, a dual-site fluorescence probe denoted as LC-1 was developed for the detection of cysteine (Cys) and its metabolite SO 3 2- . The probe was shown to be highly sensitive to Cys and SO 3 2- with a turn-on mode fluorescence signal through two emission channels under excitations at wavelengths of 320 nm and 440 nm. Notably, the LC-1 probe was also observed to be satisfactorily sensitive to Cys and SO 3 2- in the presence of other amino acids and reactive oxygen species (ROS). Meanwhile, LC-1 was shown to have low cytotoxicity and was successfully applied for imaging the metabolism of Cys in living cells.