Two-Photon Near Infrared Fluorescent Turn-On Probe Toward Cysteine and Its Imaging Applications

Two-photon excitable (850 nm) NIR fluorescent turn-on (702 nm) probe TP-NIR was synthesized for selective detection of cysteine (Cys). The probe itself shows is turned on by reaction with Cys in aqueous buffer. In addition, the probe displays greater selectivity for Cys over other thiols, including glutathione (GSH) and homocysteine (Hcy). Moreover, the large Stokes shift, NIR excitation, and NIR emission make this probe suitable for biological imaging.