Reversible and Dynamic Fluorescence Imaging of Cellular Redox Self-Regulation Using Fast-Responsive Near-Infrared Ge-Pyronines

• Published in: ACS applied materials & interfaces 2016-04, Vol.8 (14), p.8991-8997
• Main Authors: Nie, Hailiang, Jing, Jing, Tian, Yong, Yang, Wen, Zhang, Rubo, Zhang, Xiaoling
• Format: Article
• Language: English
• Subjects: Antioxidants - administration & dosage; Antioxidants - chemistry; Cell Line; Cell Membrane Permeability - drug effects; Fluorescence; Glutathione - administration & dosage; Glutathione - chemistry; Humans; Optical Imaging - methods; Oxidation-Reduction - drug effects; Oxidative Stress - drug effects; Pyronine - administration & dosage; Pyronine - chemistry; Reactive Oxygen Species - metabolism; Sulfhydryl Compounds - chemistry
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.6b01348

Cellular self-regulation of reactive oxygen species (ROS) stress via glutathione (GSH) antioxidant repair plays a crucial role in maintaining redox balance, which affects various physiological and pathological pathways. In this work, we developed a simple yet effective strategy for reversible, dynamic, and real-time fluorescence imaging of ROS stress and GSH repair, based on novel Ge-pyronine dyes (GePs). Unlike the current O-pyronine (OP) dye, the fluorescence of GePs can be quenched in GSH reduction and then greatly restored by ROS (e.g., ClO–, ONOO–, and HO•) oxidation because of their unique affinity toward thiols. The “on–off” and “off–on” fluorescence switch can complete in 10 and 20 s, respectively, and exhibit excellent reversibility in vitro and in cells. GePs also show excitation in the long wavelength from the deep-red to near-infrared (NIR) (621–662 nm) region, high fluorescence quantum yield (Φfl = 0.32–0.44) in aqueous media, and excellent cell permeability. Our results demonstrated that GePs can be used for real-time monitoring of the reversible and dynamic interconversion between ROS oxidation and GSH reduction in living cells. GePs might be a useful tool for investigating various redox-related physiological and pathological pathways.