A Reversible NIR Fluorescent Probe for Monitoring of SO2 and Formaldehyde in Live Cells and Zebrafish

Sulfur dioxide (SO2) and formaldehyde (FA) are primary pollutants that are discharged by factories, and they can interact with each other to form secondary organic aerosols that harm human health. In organisms, SO2 can be produced by cysteine, which is also a component of GSH. The deficiency of GSH will affect the metabolism of FA. With that in mind, we developed a fluorescent probe CB-NIR that can be used to reversibly detect the volatility of SO2 and FA in vitro and in vivo in real time. The probe CB-NIR connects benzopyrylium and coumarin with conjugate bridge to reversibly detect SO2 and FA, which can emit longer NIR wavelengths. Accordingly, CB-NIR have many optical advantages, such as, high sensitivity, excellent selectivity, fast response in forward and reverse directions, large emission shift, good reversibility and naked-eye observation. In addition, to our knowledge, CBNIR is the first reversible probe for SO2 and FA with fluorescence emission wavelength exceeding 700 nm. Furthermore, the probe can not only detect the volatility of SO2 and FA in organisms, but also monitor the time dependent SO2 and FA changes in real time.