Construction of novel coumarin-carbazole-based fluorescent probe for tracking of endogenous and exogenous H2S in vivo with yellow-emission and large Stokes shift

Recent medical studies have confirmed that endogenous H2S serves as the third gas-messenger besides nitric oxide (NO) and carbon monoxide (CO), which is produced by enzyme-catalyzed metabolism of cysteine and takes part in multiple physiological processes. The abnormal levels induced by H2S overproduction in mammals can destroy tissues and organ systems, which lead to certain serious diseases, such as neurodegenerative diseases, cardiovascular diseases, and various cancers. In this work, we developed a novel coumarin-carbazole fluorescent probe COZ-DNB with yellow emission and a large Stokes shift for H2S detection. In probe COZ-DNB, the newly dye COZ-OH as a luminophore and the 2,4-dinitrophenyl ether moiety was chosen as a trigger group for H2S. Probe COZ-DNB itself displayed nearly non-fluorescent. However, COZ-DNB gave the remarkable fluorescence with an 83-fold enhancement in the yellow region after interaction with H2S. The sensing mechanism of COZ-DNB toward H2S was checked by means of UHPLC, HRMS and DFT/TD-DFT calculations. What's more, probe COZ-DNB also exhibited fast response (2.0 min), high sensitivity (65.0 nM), a large Stokes shift (161.0 nm), high stability and excellent selectivity. Furthermore, COZ-DNB was applied for imaging of exogenous and endogenous H2S in living HeLa cells and zebrafish with satisfactory performances. We anticipate COZ-DNB would be served as a potential tool for investigating the biological functions of H2S in pathological processes.