A long-wavelength fluorescent probe with a large Stokes shift for lysosome-targeted imaging of Cys and GSH

A long-wavelength fluorescent probe with a large Stokes shift for lysosome-targeted imaging of Cys and GSH. [Display omitted] •Near-Infrared fluorescent probe with a large Stokes shift (180 nm).•High selectivity, low detection limit and rapid response for Cys and GSH.•Low toxicity and precise locating at lysosomes in HepG2 cells.•Aromatic morpholine as the lysosome-targeting agent. Biothiols including cysteine (Cys) and glutathione (GSH) are biological signaling molecules responsible for cell detoxification, cell metabolism and neutralization of reactive oxygen species. Here, we synthesized a long-wavelength fluorescent probe, DCIMA, for lysosome-targeted imaging of Cys and GSH in living cells. DCIMA is consisted of a dicyanoisophorone core modified with an acrylate group for biothiol detection through the Michael addition reaction and a morpholine group as the lysosome-targeting agent. The presence of the electron-donating morpholine group also enhances the intramolecular charge transfer mechanism of the probe, thereby enabling its long-wavelength fluorescence emission (670 nm) and large Stokes shift (180 nm). In concentration range of 0–30 μM, the probe was determined to react quickly with both Cys and GSH with low detection limits (