Quantitative Monitoring and Visualization of Hydrogen Sulfide In Vivo Using a Luminescent Probe Based on a Ruthenium(II) Complex.

Development of novel bioanalytical methods for monitoring of H2 S is key toward understanding the physiological and pathological functions of this gasotransmitter in live organisms. A ruthenium(II)-complex-based luminescence probe, Ru-MDB (MDB: 4'-methyl-[2,2'-bipyridine]-4-yl)methyl 2-((2,4-dinitrophenyl)thio)benzoate), was developed by introducing a new H2 S responsive masking moiety to a red-emitting RuII luminophore. Cleavage of this masking group by a H2 S-triggered reaction leads to a luminescence "off-on" response. The long-lived emissions of Ru-MDB and its reaction product with H2 S allowed quantitative detection of H2 S in autofluorescence-rich human sera and adult zebrafish organs using the time-gated luminescence mode. Ru-MDB exhibits red emission, a large Stokes shift, high specificity and sensitivity for H2 S detection, and low cytotoxicity, which enables imaging and flow cytometry analysis of lysosomal H2 S generation in live inflamed cells under drug stimulation. Monitoring of H2 S in live Daphnia magna, zebrafish embryos, adult zebrafish, and mice, was conducted by in vivo imaging using Ru-MDB as a probe.