A novel ratiometric fluorescent probe for differential detection of HSO3− and ClO− and application in cell imaging and tumor recognition

By connecting 1,8-naphthalimide and indole sulfonate, a ratio fluorescent probe capable of differential detection of hydrogen sulfite and hypochlorite was synthesized for the first time. It was able to achieve the qualitative detection of HSO3− and ClO− with high sensitivity and selectivity, respectively. It provides a multi-purpose probe and is based on different emission channels without mutual interference. The probe has the advantages of larger Stokes shift (ClO−: 115 nm, HSO3−: 88 nm), longer λem (ClO−: 515 nm, HSO3−: 548 nm) and better water solubility (DMF/PBS = 1:99, v/v). In addition, the probe is a ratio fluorescence probe, which can detect fluorescence intensity with two different emission waves. It provides internal self-calibration, reduces interference from the background and increases detection accuracy. In vitro cytotoxicity and imaging experiments show that the probe can effectively perform the detection of exogenous HSO3− and ClO− in cells. It can also achieve the detection of HSO3− and ClO− in the plasma environment. Because the probe can detect endogenous ClO−, it also has a good prospect for biological application in identifying tumor cells. Graphical abstract