A selective coumarin-based turn-on fluorescent sensor for the detection of cysteine and its applications for bioimaging

A coumarin-based compound (1) was designed and synthesized as a new turn-on fluorescent probe for the detection of cysteine. The probe exhibited higher selectivity towards the target molecule over other thiol and amino acids at pH 7.2 in aqueous media CH3CN-HEPES (0.02 mol/L, pH 7.2,1:9, v/v). The reaction mechanism is attributed to the cysteine-induced SNAr substitution-rearrangement reaction. Remarkable enhancement of up to 20-fold in fluorescence intensity was achieved in the detection of cysteine. When applied for the fluorescence imaging of cysteine, the compound 1 emitted a green fluorescence in Hi5 cell cytoplasm. The in vivo imaging of Caenorhabdiris elegans had further confirmed the cysteine detection by compound 1. (C) 2017 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.