Thrombin-mediated ratiometric two-photon fluorescent probe for selective imaging of endogenous ultratrace glutathione in platelet

Ultratrace change of reduced glutathione (GSH) can weaken coagulation function of platelet (PLT). Thus, rapid and sensitive imaging of GSH specific in PLT is beneficial for monitoring coagulation function of PLT. Many fluorescent probes for GSH have been reported, but ratio fluorescent probe with excellent two-photon property for screening PLT from peripheral blood and quantitative imaging of GSH are scarce. In this work, a thrombin-mediated two-photon GSH-specific fluorescent probe (IQDC-L) was reported. Sulfuric diamide, a key group as linker, was introduced into IQDC-L, which resulted in not only specific selectivity for GSH, but also FRET occurring in probe. When IQDC-L encountered GSH, “S-N” in sulfonamide group was cut off, and FRET was inhibited. Furthermore, fluorescence intensities at 520 and 595 nm presented linear change on ratio mode in the range of GSH (2.0-65 nM). The lowest detection for GSH was as low as 0.083 nM. Intriguingly, IQDC-L under thrombin-mediated was able to screen PLT from peripheral blood without any interference. Thus, IQDC-L could be used to screen PLT from peripheral blood, and simultaneously, to in situ image ultratrace GSH.