A near-infrared turn on fluorescent probe for biothiols detection and its application in living cells

Cysteine (Cys), homocysteine (Hcy) and Glutathione (GSH) are small-molecular biothiols that play key roles in various biological systems. The development of fluorescent probes for thiols has attracted intense interest. Inspired by the appealing advantages of near-infrared (NIR) fluorescent detection, we herein report a novel NIR fluorescent probe for biothiols detection based on the widely-used thiol-selective 2,4-dinitro-benzenesulfonyl (DNBS) group. The probe is intrinsically nonfluorescent; however, after being reacted with thiols, the DNBS group is substituted by the -SH group, which elicits a significant NIR fluorescent turn-on response. Probe displays 160-fold fluorescence intensity enhancement at 688 nm with 2 equiv of Cys in neutral buffer. More importantly, the probe features a good linearity range and the detection limit is as low as 63 nM. In addition, the probe uses long wavelength excitation (620 nm), all of such good properties proving it to be a good sensor for the selective detection of thiols and a potential use in biological applications. (C) 2017 Elsevier B.V. All rights reserved.