Construction of a mitochondria-targeted near-infrared fluorescence turn-on fluorescent probe for H2S detection and imaging in living cells and drug-induced mice inflammatory models

The mechanism of the interaction between the signaling molecule hydrogen sulfide (H2S) and mitochondria and its related diseases is difficult to elusive. Thus it is urgent to develop effective methods and tools to visualize H2S in mitochondria and in vivo. In this work, a robust mitochondrial-targeting NIR fluorescence "turn-on" fluorescent probe, NIR1, was reported, by adopting a Changsha-OH near-infrared (NIR) dye as the NIR fluorophore, a 2,4-dinitrophenyl (DNB) moiety as both the responsive site of the H2S and the fluorescence quenching group of the NIR fluorophore, and an oxygen onium ion site as the mitochondria-targeting group, for the detection and analysis of H2S in living Raw 264.7 cells and drug-induced inflammatory mice models. NIR1 exhibited a much smaller background fluorescence signal in lack of H2S, whereas strong enhanced NIR fluorescence "turn-on" was detected in the presence of H2S, these results showed a low detection limit (30.2 nM) for quantitative detection of H2S in aqueous solutions with concentrations ranging from 0 to 1 μM H2S. These characteristics were beneficial to direct detection and imaging analysis of H2S in complicated biosystems. Therefore, first, NIR1 was applied for the NIR detection of mitochondrial H2S in living inflammatory cells with satisfactory results. Finally, NIR1 was applied to detect H2S in drug-induced inflammatory mice models with agreeable results, demonstrating that NIR1 as a molecular tool has an excellent practical application in the study of the interaction between inflammatory and H2S.