Light-driven visualization of endogenous cysteine, homocysteine, and glutathione using a near-infrared fluorescent probe

Herein, we presented a hydrosoluble triple-site and triple-excitation alternative NIR fluorescent probe for visualization of endogenous biothiols in phosphate-buffered saline (pH 7.4, 10 mM). Upon irradiation using different excitation light, probe 1 exhibited different fluorescence responses upon the addition of Cys, Hcy, and GSH: lambda(ex) = 419 nm, lambda(em) = 498 nm; lambda(ex) = 518 nm, lambda(em) = 573, 616, 727, and 783 nm; lambda(ex) = 555 nm, lambda(em) = 612 and 727 nm, respectively. Furthermore, 1 was favourably applied for bioimaging endogenous Cys, Hcy, and GSH in A375 cells through well-defined blue-green-red emission channels.