A bioorthogonal fluorescent probe for mitochondrial hydrogen sulfide: new strategy for cancer cell labeling.

We report the application of a chemodosimeter 'turn on' fluorescent probe for detecting endogenous H2S formation in cancer cells. Mito-HS showed a bathochromic shift in the UV-vis-absorption spectrum from 355 nm to 395 nm in the presence of H2S. Furthermore, it showed an ∼43-fold fluorescence enhancement at λem = 450 nm in the presence of H2S (200 μM). The cancer cell-specific fluorescence imaging reveals that Mito-HS has the ability to distinguish cancer cells from normal cells based on the level of endogenous H2S formation. In due course, Mito-HS would be a powerful cancer biomarker based on its ability to estimate endogenous H2S formation in living cells.