A NBD-S-rhodamine dyad for dual-color discriminative imaging of biothiols and Cys/Hcy

Abstract

Biothiols are essential biomolecules in sustaining intracellular redox homeostasis. Abnormal levels of Cys, Hcy, GSH and H₂S are linked to different diseases, respectively. Although many fluorescent probes are successfully applied in the detection of these biothiols in living biological samples, probes with high selectivity to discriminatively detect biothiols are underdeveloped. Herein, we designed and synthesized a new dual-color NBD-S-rhodamine fluorescent probe based on fast thiolysis of NBD thioether, a non-thiol-consuming receptor. This probe could react with GSH/H₂S to give red fluorescence, and with Cys/Hcy to give both green and red fluorescence for discriminative detection of biothiols and Cys/Hcy. The results revealed that this probe exhibited good selectivity and high sensitivity toward biothiols, and could be used in bioimaging. Based on the probe tool, we could selectively detect Cys/Hcy in the presence of GSH in living mammalian cells.