Cyanine-coumarin composite NIR dye based instantaneous-response probe for biothiols detection and oxidative stress assessment of mitochondria

Developing near-infrared (NIR) dye based functional fluorescent probes to analysis the bioactive substances contributes to the understanding of cellular physiopathology. Although there are many fluorescent probes have been developed, the probes can instantaneous response to biothiols is still lacking. In this study, we have designed and synthesized a novel composite NIR dye (Hcyc), which was composed by cyanine and coumarin. Hcyc was further applied to construct a biothiols responsive probe (Hcyc-NO) to assess the oxidative stress status of mitochondria in living cells. The optical properties showed that Hcyc has long absorption and emission wavelength in different solvent system (>720 nm). Interestingly, Hcyc-NO could respond to GSH, Cys, Hcy rapidly (<5 s), the absorption peak of red shifted from 556 nm to 723 nm and fluorescence intensity instantaneously enhanced at 751 nm after adding biothiols. In addition, Hcyc-NO prossesses others excellent sensing properties such as high selectivity and sensitivity. Confocal imaging revealed that Hcyc-NO (1 mu M) could target mitochondria and selective image biothiols (GSH, Cys and Hcy) in vitro. Furthermore, the probe could rapidly reflect oxidative stress induced by lipopolysaccharide (LPS) or phorbol myristate acetate (PMA) in vitro and in vivo. These results indicate that Hcyc is an excellent NIR dye, and the probe Hcyc-NO may be an effective tool for instantaneous detection of biothiols and real-time assessing the oxidative stress of cells.