A fluorescent probe for simultaneous discrimination of GSH and Cys/Hcy in human serum samples via distinctly-separated emissions with independent excitations

Biothiols like Cys, Hcy and GSH play important roles in various physiological and pathological processes, and it is still challenging to simultaneously and discriminatively detect GSH and Cys/Hcy due to their similar structures and reaction activities. Hence, it would be highly desirable to design a fluorescent probe for simultaneously discriminating GSH and Cys/Hcy in biological samples with no spectral crosstalk, few interferences and rapid response. Herein, through coupling two fluorophores with biothiol-sensitive linker, we developed a fluorescent probe, which has two biothiol-responsive and distinctly-separated emissions via independent visible-light excitations, for simultaneously discriminating GSH and Cys/Hcy with near-infrared and green emissions. The probe is operable in human serum samples, thus holding promise for diagnostic-related applications. Moreover, the probe shows quite good properties. First, it exhibits a rapid response (within a few minutes) with highly selective and sensitive detection for GSH and Cys/Hcy. Second, it offers an apparent colorimetric and two fluorescence emission signals without spectral crosstalk. Third, it shows low cytotoxicity. Therefore, it would provide a useful method for further elucidating the roles of biothiols as well as for conducting pathological analysis for diseases involving biothiols.