A structural optimized fluorescent probe for monitoring hydrogen sulfide in cells and zebrafish.

[Display omitted] • A benzofuranone-based fluorescent probe, Fur-SH , was developed for monitoring sulfite. • Optimization of optical properties of fluorophores by different structural modifications. • Smaller full width at half maxima, rapid response (5 min) and wide pH window. • Reliable linear range, high sensitivity, high selectivity towards sulfite. • Applied into the biological imaging of sulfite in living MCF-7 cells and in zebrafish. In this work, we reported a fluorescent probe Fur-SH , a derivative of benzofuranone, which was used to detect H 2 S in living cells and zebrafish. Based on the three structural characteristics of the probe, the effects of different structural modifications on the optical properties of the fluorophore were compared. Then, the fluorophore Fur-OH was synthesized by modifying diethylamino group with benzofuranone as the main skeleton. With 2,4-dinitrofluorobenzene as the recognition group and diethylamino as the electron donor, the push–pull electron effect occurred with nitro group, which led to fluorescence quenching, and an openable fluorescent probe Fur-SH was formed. The probe Fur-SH (λ ex = 510 nm; λ em = 570 nm) had the advantages of smaller full width at half maxima, rapid response (5 min) and wide pH window. The quantitative properties of the probe were excellent, reaching saturation at 50 equivalents of substrate. The probe Fur-SH showed high sensitivity to H 2 S, with LOD of 48.9 nM and LOQ of 50 nM. At present, the probe Fur-SH had been applied to fluorescence imaging of MCF-7 cells and zebrafish. By comparing the effects of different structures on the optical properties of fluorophores, this work was expected to be helpful to the development of fluorescent probes in the future. [ABSTRACT FROM AUTHOR]