Bifunctional near-infrared fluorescent probe for the selective detection of bisulfite and hypochlorous acid in food, water samples and in vivo

We report the development of a bifunctional near-infrared fluorescent probe (QZB) for selective sensing of bisulfite (HSO3-) and hypochlorous acid (HOCl). The synergistic detection of HSO3- and HOCl was achieved via a C=C bond recognition site. In comparison with the red-fluorescence QZB, two different products with non-fluorescence and paleturquoise fluorescence were produced by the recognition of QZB towards HSO3- and HOCl respectively, which can realize effectively the dual-functional detection of HSO3- and HOCl. QZB features prominent preponderances of dual-function response, near-infrared emission, reliability at physiological pH, low cytotoxicity and high sensitivity to HSO3- and HOCl. The detection of HSO3- in actual food samples has been successfully achieved using QZB. Utilization of QZB-based test strip to semi-quantitatively detect HSO3- and HOCl in real-world water samples by the "naked-eye" colorimetry are then demonstrated. Simultaneously, the determination of HSO3- and HOCl in real-world water sample has been achieved by smartphone-based standard curves. Additionally, the applications of QZB for imaging HSO3- and HOCl in vivo are successfully demonstrated. Consequently, the successful development of QZB could be promising as an efficient tool for researching the role of HSO3-/HOCl in the regulation of redox homeostasis regulation in vivo and complex signal transduction and for future food safety evaluation.