ESIPT Fluorescence Probe Based on Double-Switch Recognition Mechanism for Selective and Rapid Detection of Hydrogen Sulfide in Living Cells

[Image: see text] A novel fluorescence probe, HBTSeSe, was designed and synthesized for the detection of H(2)S with a double-switch mechanism of a broken diselenide bond followed by thiolysis of ether. Then, 2-(2′-hydroxyphenyl)benzothiazole (HBT) was released as fluorophore, which has large Stokes shift based on the excited state intramolecular proton transfer process. The probe responded selectively and rapidly to H(2)S, with the fluorescence increased by 47-fold immediately after the addition of H(2)S. HBTSeSe was able to detect H(2)S in the cytoplasm, specifically in cell imaging experiments. The results also showed that H(2)S was produced in the immune response of RAW264.7 cells activated by phorbol-12-myristate-13-acetate.