A novel red-emission fluorescent probe for the detection of cysteine in vitro and in vivo.

[Display omitted] • HL-Cys showed red-emission fluorescence and its Stokes shift was more than 100 nm. • HL-Cys with hypotoxicity and low detection limit (0.58 µM) was successfully used to the imaging of Cys in vitro and in vivo. In this work, a novel red-emission fluorescent probe (HL-Cys) based on benzothiazole moiety was designed and synthesized for the detection of cysteine (Cys). HL-Cys could display specific fluorescence response toward Cys over other analytes including amino acids and GSH at 620 nm (E x = 513 nm) because of the Michael addition reaction between Cys and HL-Cys, leading to the cleavage of acryloyl group from the parent ligand (HL). Moreover, HL-Cys with hypotoxicity and low detection limit was successfully used to the imaging of Cys in vitro and in vivo. [ABSTRACT FROM AUTHOR]