Mitochondria-targeted NIR fluorescent probe for reversible imaging H2O2/SO2 redox dynamics in vivo

Mitochondria are a vital organelle of eukaryotic cell which plays essential roles in many physiological processes. Sulfur dioxide (SO2) and hydrogen peroxide (H2O2), as two kinds of vital signal molecule and biomarker, can be endogenously generated by metabolism process in mitochondria of living cells. Recent studies revealed that SO2 and H2O2 was also a redox pairs, however, the biological function of these two species is elusive. Aiming to elucidate their complicated roles in regulating oxidative stress, for the first time we have successfully developed a Mitochondria-targeted NIR fluorescent probe which reversible response of H2O2/SO2 dynamics in vitro and vivo. The responsive mechanism was proved to be nucleophilic addition of SO2 derivatives to highly reactive double bonds in the probe 1. And importantly, we found that the SO2 addition adducts could be oxidized and turned into probe 1 by H2O2. Furthermore, probe 1 has been applied for imaging the SO2/H2O2 redox dynamics in living cells and mice model.