Construction of a ratiometric fluorescent probe for discriminative detection of SO2 derivatives and Cys and its bio-imaging application

Endogenous sulfur dioxide (SO2) and cysteine (Cys) are important species and interacted with each other. However, due to the reactivity of these species, it is difficult to differentiated detection them. Thus, it is necessary to develop new fluorescent probe for discriminative detect these reactive sulfur species in biological environment. Herein, A new hemicyanine derivative Mito-AE with dual recognition sites for SO2 derivatives and Cys detection was constructed and applied in biological detection. Mito-AE exhibited ratiometric fluorescence change (F470/F610) of over 90-fold when interacted with SO2, and a dramatic fluorescence turn-on at 610 nm when interacted with Cys. The probe can monitor both SO2 derivatives and Cys with fast response rate (within 1 min), high sensitivity and selectivity. As proved by biological experiments, Mito-AE was able to successfully detect exogenous and endogenous SO2 in living cells as well as in mitochondria area. More importantly, the detection of SO2 derivatives and Cys in zebrafish model suggesting a potential application for studying the multiple interaction of biological sulfurous species in live organism.