A single fluorescent probe for imaging ribonucleic acid and sulfur dioxide in living systems and its unique application in tumor and normal cells.

To investigate the unique interrelation of ribonucleic acid (RNA) and sulfur dioxide (SO2) in living systems, it is necessary to construct novel molecular tools that could detect RNA and SO2 in living cancer cells and animals. Herein, we have constructed a unique fluorescent probe, EPI-RS, for imaging RNA and SO2 with distinct fluorescence signals in living systems. This type of probe shows a series of advantages, such as high photostability, large Stokes shift, high selectivity and sensitivity in a pure water system. In light of these advantages, the probe EPI-RS was employed to image RNA and SO2 by "turn on" and "turn off" fluorescence signals in living cells, tissues, zebrafish and mice. Interestingly, the probe EPI-RS exhibits different in vivo imaging properties in normal and tumor cells.