Hydro-soluble NIR fluorescent probe with multiple sites and multiple excitations for distinguishing visualization of endogenous Cys/Hcy, and GSH

Small molecular biothiols (Cys, Hcy, and GSH) are intimately related to complicated metabolic process. On account of the analogous chemical construction and reactivity, it is still a challenging problem to diacritically detect biothiols, which seriously hinders people's understanding of their metabolic relationship and the reasons for biothiols-related illnesses. Therefore, a hydro-soluble NIR fluorescent probe (YF) with multiple sites and multiple excitations was designed for distinguishing biothiols. Across different excitation, YF displayed unique fluorescence signals: λex = 418 nm, λem = ∼496 nm; λex = 517 nm, λem = ∼576/733/783 nm; λex = 558 nm, λem = ∼611/733 nm, respectively. As far as we know, the different reaction mechanism that leading to different spectroscopic behaviors of YF towards biothiols were confirmed by DFT calculation for the first time. Significantly, YF was successfully applied to recognize Cys/Hcy, and GSH in A375 cells from different emission channels, and was determination of biothiols in fetal bovine serum samples and the result was in good agreement with that tested by Ellman method.