Reversible Ratiometric Fluorescent Probe for Sensing Bisulfate/H₂O₂ and Its Application in Zebrafish

Herein, a novel near-infrared fluorescent probe for ratiometric detection of bisulfate was designed and developed based on a conjugation of naphthopyran-benzothiazolium system. The sensor showed excellent selectivity, high sensitivity and a rapid response toward bisulfite in aqueous solution. Upon the addition of HSO₃^-, the sensor displayed 37-fold (I₅₂₀/I₆₃₀) fluorescence intensity enhancement, accompanied by an apparent color change from violet to colorless, suggesting that the sensor can be used to detect HSO₃^- with "naked-eye". Notably, the addition product can be applied to the design of regenerative chemodosimeters based on the H₂O₂ promoted elimination of bisulfite and recovery of probe 1. Further cell and zebrafish imaging experiment demonstrated that the sensor could image the bisulfite/H₂O₂ redox cycle in biological system with ratiometric manners.