Construction of an in vivo NIR fluorescent probe for revealing the correlation between inflammation and mitochondrial hydrogen sulfide and viscosity

As an indispensable part of immune response, inflammation plays a critical role in the occurring and advancing of many diseases. It is reported that the emergence of inflammation can be indicated by the change of intracellular viscosity and overexpression of the hydrogen sulfide (H2S) in mitochondria. So far, elucidating the relationship between inflammation and the above parameters remains a challenge due to the lack of validated analytical tools. Herein, a novel dual-function NIR fluorescent probe CMQT with excellent biological compatibility and mitochondrial targeting ability is designed and synthesized by using 7-diethylaminocoumarin and 4-ethylphenolate quinoline acetate through twistable vinyl bonds. With the functional probe, enhanced fluorescent signals at 570 nm and 721 nm are produced in the presence of H2S and changes of viscosity. The CMQT can be applied in living cells and zebrafish, which reveals the increases of mitochondrial H2S and viscosity generated by inflammatory response through dual-channel fluorescence imaging mode. The in vivo dual-functional probe serves as an efficient tool for imaging analysis of H2S and viscosity, and has profound implications for the early diagnosis of inflammatory diseases.