Dual-Channel fluorescent detection of Biothiols: A novel probe for Distinguishing Cysteine, Homocysteine, Glutathione, and N-Acetylcysteine in cellular environments.

Biothiols, including cysteine (Cys), homocysteine (Hcy), glutathione (GSH), and N-acetylcysteine (NAC), possess similar chemical structures and properties but play crucial, distinct roles in biological cells and blood serum. Imbalances in the concentrations of these biothiols are associated with various diseases, highlighting the importance of precise discrimination, especially between Cys and other biothiols. Owing to the similarity of the chemical properties of Cys, Hcy, GSH, and NAC, developing an effective methodology to differentiate these thiol compounds is challenging. In this study, we designed and synthesized a novel dual-channel fluorescent probe, hereafter referred to as CNTC, by integrating coumarin and acrylonitrile. This probe enabled the simultaneous discrimination of Cys from Hcy, GSH, and NAC, producing distinct fluorescent signals: blue for Cys and green for Hcy, GSH, and NAC. CNTC exhibited rapid response kinetics (within 30 min) and impressive detection limits of 0.31, 0.11, 0.029, and 0.032 μM for Cys, Hcy, GSH, and NAC, respectively. Furthermore, CNTC was successfully applied in the fluorescence imaging of both exogenous and endogenous Cys, Hcy, GSH, and NAC in living cells. The remarkable analytical and bioimaging capabilities of CNTCin vivo establish it as a promising tool for elucidating the pathophysiological roles of biothiols, particularly Cys, Hcy, GSH, and NAC.