A lysosome-targetable fluorescent probe for simultaneous detection and discrimination of Cys/Hcy and GSH by dual channels

Small molecule biothiols, such as cysteine (Cys), homocysteine (Hey) and glutathione (GSH), are important biomarkers and play vital roles in many physiological processes. Due to their similarity in structure and function, it is still a challenge to develop probes that can simultaneously distinguish Cys, Hey and GSH from each other. Lysosome is a major subcellular organelle in living cells that contains approximately 50 different degradative enzymes, and biothiols play an important role in lysosome. Herein, we developed a lysosome-targetable probe Lyso-O-NBD for simultaneous detection and discrimination of Cys/Hcy and GSH by dual channels. Under double-wavelength excitation of 400 nm and 470 nm, the probe Lyso-O-NBD showed high selectivity and sensitivity towards Cys/Hcy and GSH over other amino acids and ions. Furthermore, the probe Lyso-O-NBD could be used for simultaneous detection and discrimination of Cys/Hcy and GSH in lysosome of living cells with low cytotoxicity.