A ratiometric fluorescent probe for hydrogen sulfide in neat aqueous solution and its application in lysosome-targetable cell imaging.

[Display omitted] • A water-soluble merocyanine-based fluorescent probe has been developed. • The probe could monitor H 2 S via ratiometric fluorescent signal in neat aqueous solution. • The probe is sensitive toward H 2 S with a detection limit of 0.81 nM. • The probe has been successfully applied to imaging H 2 S in the lysosomes of zebrafish. Hydrogen sulfide (H 2 S) has been recently regarded as one of the most important gasotransmitters in the metabolic system, while abnormal H 2 S concentration is associated with various diseases. Although numerous fluorescent probes have been developed for the detection of cellular H 2 S, only a few of them can monitor lysosomal H 2 S with ratiometric fluorescent output. Here, we developed a water-soluble probe 1 toward H 2 S by introducing 2,4-dinitrophenyl ether into a novel merocyanine-based dye. As expected, H 2 S induced an obvious red-shift of the probe from 520 nm to 580 nm in neat aqueous solution, and this fluorescent ratiometric response is highly selective and sensitive (with the detection limit of 0.81 nM), rapid (within 10 s), and effective in a wide pH range (2.0–10.0). In particular, the probe was successfully applied for tracing H 2 S in the lysosomes of living cells and in zebrafish. [ABSTRACT FROM AUTHOR]