A novel fluorescent probe for rapid detection of sulfur dioxide in living cells.

Sulfur dioxide (SO2 ) is one of the reactive sulfur species, which has significant physiological functions in cells. Some physiological processes are closely related to SO2 in organisms, and the high concentration of SO2 in living cells can cause many diseases. In order to investigate the unique function of sulfur dioxide (SO2 ) in subcellular level, developing a molecular tool which could detect of SO2 within organelles is imperative. Hence, we developed a cationic dye named HQ-SO2 as a new fluorescent probe to specifically monitor SO2 , which was easy to obtain through one-step reaction. It took Michael addition reaction as the mechanism of reaction for detection of SO2 . In addition, this probe showed a series of highly favorable properties such as rapid response rate, low cytotoxicity, high selectivity, low detection limit, and good photostability, which enabled the probe to track SO2 in living cells.