Dual-functional probes for sequential thiol and redox homeostasis sensing in live cells.

A new type of resorufin-based dual-functional fluorescent probe whose fluorescence emission features are sensitive to thiol compounds and redox homeostasis was developed. Thiols-triggered nucleophilic substitution of the probes converts the nonfluorescent probe to the highly fluorescent resorufin moiety; the released resorufin not only enables fluorescence signaling specific for thiol compounds but functions as a redox indicator with sensitive colorimetric and fluorescence emission change upon redox variation. Preliminary fluorescence imaging experiments have revealed the biocompatibility of the as-prepared probes and validated their practicability for thiol sensing and redox homeostasis mapping in living cells.