A near-infrared fluorescent probe based on SNAr reaction for H2S/GSH detection in living cells and zebrafish

Hydrogen sulfide (H2S) and biothiols such as cysteine (Cys), homocysteine (Hcy) and glutathione (GSH), play critical roles in physiological and pathological processes. However, due to the challenge in sensing H2S and biothiols simultaneously, it is of great importance to solve this problem in biological processes. Herein, a near-infrared fluorescent probe (HZ-NBD) based on SNAr reactions was exploited to achieve the sensitive and selective detection of H2S and glutathione (GSH) simultaneously in the same conditions. The design strategy was employing dicyanoisophorone based fluorescent dye as the fluorophore, the NBD moiety as a response unit and a quencher of fluorophore. The probe exhibited a low limit of detection to H2S (13.2 nM) and GSH (112 nM) as well as a favourable large stokes shift (112 nm). The reaction mechanism was investigated via mass spectra. What's more, owing to the advantages of low cytotoxicity, fast response and strong anti-interference ability, the probe HZ-NBD was successfully applied to bioimage H2S and GSH in HepG2 cells and zebrafish.