A multicolor reversible fluorescent probe for detecting SO2 and H2O2: Revealing redox imbalance in ischemia-reperfusion model

The redox homeostasis between hydrogen peroxide (H2O2) and sulfur dioxide (SO2) is necessary to maintain the normal physiological function of biological system. However, Due to the lack of fluorescent probes for the reversible dual detection of SO2 and H2O2, it is not clear which of the above signaling molecules predominates to cause redox state imbalance in biological systems. Herein, we designed a new muti-color reversible fluorescence probe Mito-BHY based on ICT mechanism. The probe has three different fluorescence signals (blue, green, and red) before and after reacting to SO2 and H2O2, and it can also reversibly detect SO2 and H2O2 through changes in the green and red fluorescence signals. The probe Mito-BHY has the characteristics of favorite response to SO2 and H2O2 with fast response speed, highly selectivity and biocompatibility, and can be used to monitor SO2 and H2O2 in the living cells and mice. Using Mito-BHY, we discovered that the content of H2O2 increased during cell redox imbalance and ischemia reperfusion in the mice, while the content of SO2 remained basically unchanged. This work will contribute to the understanding of the variation of SO2 and H2O2 levels, and is expected to provide an effective tool for pathological studies of redox imbalance.