title: A near-infrared ratiometric fluorescent probe for cysteine detection over glutathione indicating mitochondrial oxidative stress in vivo.
abstract: We establish a near-infrared (NIR) ratiometric fluorescent probe Cy-NB for the selective detection of cysteine (Cys) over glutathione (GSH) and homocysteine (Hcy) in mitochondria to indicate oxidative stress. Heptamethine cyanine dye is chosen as the fluorophore of Cy-NB whose emission locates in NIR region. And p-nitrobenzoyl is employed as the fluorescent modulator due to its capability of selective-Cys response. Once triggered by Cys, the uncaged p-nitrobenzoyl rearranges the polymethine π-electron system of the fluorophore, which leads to a remarkable spectrum shifts in absorption and emission profiles. Taking advantage of these spectroscopic properties, we construct a ratiometric fluorescent signal for the detection of Cys with a detection limit of 0.2 µM within 5 min. Our probe Cy-NB can sensitively detect the mitochondrial Cys pool changes under different oxidative stress status in HepG2 cells. We also successfully employ Cy-NB to imaging Cys level changes in living mice. It suggests that mitochondrial Cys can be used as an oxidative stress biomarker with simple potential clinical applications. And our probe Cy-NB is of great potential for further utilizing in exploring the physiological function of Cys in biological systems.
authors.affiliation: Key Laboratory of Coastal Environmental Processes and Ecological Remediation; The Research Center for Coastal Environmental Engineering and Technology, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Yin
authors.affiliation: Key Laboratory of Coastal Environmental Processes and Ecological Remediation; The Research Center for Coastal Environmental Engineering and Technology, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China. Electronic address: fbyu@yic.ac.cn.
authors.forename: Fabiao
authors.initials: F
authors.lastname: Yu
authors.affiliation: Key Laboratory of Coastal Environmental Processes and Ecological Remediation; The Research Center for Coastal Environmental Engineering and Technology, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; School of Marine Sciences, Ningbo University, Ningbo 315211, China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Coastal Environmental Processes and Ecological Remediation; The Research Center for Coastal Environmental Engineering and Technology, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China. Electronic address: lxchen@yic.ac.cn.
authors.forename: Lingxin
authors.initials: L
authors.lastname: Chen
mesh_terms: D000818:Animals; D015374:Biosensing Techniques; D003545:Cysteine / Q000032:analysis*; D005456:Fluorescent Dyes / Q000737:chemistry*; D005978:Glutathione / Q000032:analysis*; D056945:Hep G2 Cells; D006801:Humans; D057230:Limit of Detection; D008807:Mice, Inbred BALB C; D008928:Mitochondria / Q000737:chemistry*; D061848:Optical Imaging; D018384:Oxidative Stress; D013050:Spectrometry, Fluorescence
chemical_list: D005456:Fluorescent Dyes; D005978:Glutathione; D003545:Cysteine
keywords: Cysteine; Image analysis; Mitochondria; Oxidative stress; Ratiometric fluorescence