A highly selective fluorescent chemodosimeter for imaging hydrogen sulfide in living cells

A 2-formylbenzoate-caged methylfluorescein chemodosimeter (1) was designed and synthesized to detect hydrogen sulfide (H₂S) in aqueous solution and living cells. Chemodosimeter 1 could quantificationally detect H ₂S in a wide concentration range (2.5-1000 μM) by the fluorescence turn-on method. Chemodosimeter 1 showed excellent selectivity toward H ₂S owing to its inherent two electrophilic reaction sites and the dual nucleophilicity of H₂S. Additionally, chemodosimeter 1 exhibited the color changes from colorless to yellow-green upon addition of H ₂S. Thus, 1 can serve as a "naked-eye" indicator for H ₂S. Further, the recognition mechanism of chemodosimeter 1 for H ₂S was confirmed using electrospray ionization mass spectrometry. Finally, the preliminary biological imaging experiments and low cytotoxicity investigations demonstrated that our proposed chemodosimeter provided a promising method for the determination of H₂S in aqueous solution and living cells.