A ratiometric fluorescence probe with large stokes based on excited-stated intramolecular proton transfer (ESIPT) for rapid detection and imaging of biothiols in human liver cancer HepG2 cells and zebrafish

The development of biothiol fluorescent probes is of great significance in life sciences and clinical medicine. In the present study, a novel fluorescent probe, 2-(benzo[d]thiazol-2-yl)-1,4-phenylene bis(2,4-dinitrobenzenesulfonate) (BTPB), was synthesized and characterized by NMR and HRMS. BTPB can selectively detect biothiols over other analytes in a DMSO-HEPES solution, taking the advantages of low cytotoxicity, a large Stokes shift (160 nm) and a low detection limit (0.174–0.399 μM). The fluorescence response of BTPB to calf serum and the test strip provided strong evidence of the practical applicability. In addition, the probe was successfully applied in imaging of HepG2 cells and zebrafish.