Rational design of a dual-reactive probe for imaging the biogenesis of both H2S and GSH from l-Cys rather than d-Cys in live cells

Abstract

Biothiols and their interconversion are involved in cellular redox homeostasis as well as many physiological processes. Here, a dual-reactive dual-quenching fluorescent probe was rationally developed based on thiolysis reactions of 7-nitrobenzoxadiazole (NBD) tertiary amine and 7-cyanobenzoxadiazole (CBD) arylether for imaging of the biothiol interconversion. We demonstrate that the NBD-CBD probe exhibits very weak background fluorescence due to the dual-quenching effects, and can be dual-activated by H₂S and GSH with an over 500-fold fluorescence increase at 525 nm. In addition, the probe shows high sensitivity, excellent selectivity, and good biocompatibility, all of which promote the simultaneous detection of both H₂S and GSH in live cells. Importantly, probe 1 was successfully employed to reveal the biogenesis of both H₂S and GSH from L-Cys rather than from D-Cys, and therefore, D-Cys would be solely converted into H₂S, which may help understand the more H₂S generation from D-Cys than from L-Cys in live cells.