A Dual-Response Fluorescent Probe for the Detection of Viscosity and H2S and Its Application in Studying Their Cross-Talk Influence in Mitochondria

Intracellular viscosity is an essential microenvironmental parameter and H2S is a critical gaseous signaling molecule, which are both related to various physiological processes. It is reported that the change of viscosity and an imbalance of H2S production in the mitochondria are both associated with overexpression of amyloid betapeptide (Aβ), which is thought to play a central role in the pathogenesis of Alzheimer’s disease (AD). However, to our best knowledge, no fluorescent probe is found for dual detection of mitochondrial viscosity and H2S. Herein, a dual-response fluorescent probe (Mito-VS) is designed and synthesized to monitor the level of viscosity and H2S, respectively. Mito-VS itself is nonfluorescent due to a free intramolecular rotation between dimethylaniline and pyridine. After the increase of viscosity, the rotation is prohibited and an intense red fluorescence is released. Upon the addition of H2S, the probe can react with H2S to form compound 3 and a strong green fluorescence can be obse...