Dual-Site Chemosensor for Monitoring ?OH-Cysteine Redox in Cells and In Vivo

The reaction between hydroxyl radical (middotOH) and cysteine (Cys) plays an important role in the redox balance of living cells. A deeper insight into this intracellular reaction modulation and process is necessary and draws great interest. A highly effective technique consists of the real-time visualization of the two bioactive species and the perception of their respective changes by using a fluorescent probe. In this study, a dual-site chemosensor SPI based on phenothiazine-cyanine was developed, which realized quantitative detection and real-time imaging of middotOH and Cys at their own fluorescence channels (middotOH: "ex = 485 nm, "em = 608 nm; Cys: "ex = 426 nm, "em = 538 nm) without spectral crosstalk. The fluorescent sensor showed excellent anti-interfer-ence and selectivity for common biological substances, apart from the successful imaging of exogenous and endogenous middotOH and Cys. We further visualized the redox dynamic reaction and explored the correlation of middotOH and Cys generated by different inhibitors (sulfasalazine and (1S, 3R)-RSL3). Notably, the chemosensor also possesses the capacity to clearly monitor middotOH and Cys in living mice and zebrafish. This study reports on the first chemosensor to investigate the process of intracellular redox modulation and control between middotOH and Cys, which show potential to further explore some metabolic and physiological mechanisms.