title: Carbon quantum dots directly generated from electrochemical oxidation of graphite electrodes in alkaline alcohols and the applications for specific ferric ion detection and cell imaging.
abstract: Carbon quantum dots (CQDs) are attracting tremendous interest owing to their low toxicity, water dispersibility, biocompatibility, optical properties and wide applicability. Herein, CQDs with an average diameter of (4.0 ± 0.2) nm and high crystallinity were produced simply from the electrochemical oxidation of a graphite electrode in alkaline alcohols. The as-formed CQDs dispersion was colourless but the dispersion gradually changed to bright yellow when stored in ambient conditions. Based on UV-Vis absorption, fluorescence spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and high-resolution transmission electron microscopy (HRTEM), this colour change appeared to be due to oxygenation of surface species over time. Furthermore, the CQDs were used in specific and sensitive detection of ferric ion (Fe(3+)) with broad linear ranges of 10-200 μM with a low limit of detection of 1.8 μM (S/N = 3). The application of the CQDs for Fe(3+) detection in tap water was demonstrated and the possible mechanism was also discussed. Finally, based on their good characteristics of low cytotoxicity and excellent biocompatibility, the CQDs were successfully applied to cell imaging.
authors.affiliation: College of Materials Science and Engineering; Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory; Collaborative Innovation Center for Marine Biomass Fibers, Materials and Textiles of Shandong Province; Qingdao University, Qingdao 266071, China. jliu@qdu.edu.cn.
authors.forename: Mengli
authors.initials: M
authors.lastname: Liu
authors.affiliation: College of Materials Science and Engineering; Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory; Collaborative Innovation Center for Marine Biomass Fibers, Materials and Textiles of Shandong Province; Qingdao University, Qingdao 266071, China. jliu@qdu.edu.cn.
authors.forename: Yuanhong
authors.initials: Y
authors.lastname: Xu
authors.affiliation: College of Materials Science and Engineering; Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory; Collaborative Innovation Center for Marine Biomass Fibers, Materials and Textiles of Shandong Province; Qingdao University, Qingdao 266071, China. jliu@qdu.edu.cn.
authors.forename: Fushuang
authors.initials: F
authors.lastname: Niu
authors.affiliation: School of Chemistry, Australian Centre for NanoMedicineand ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of New South Wales, Sydney, NSW 2052, Australia. justin.gooding@unsw.edu.au.
authors.forename: J Justin
authors.initials: JJ
authors.lastname: Gooding
authors.affiliation: College of Materials Science and Engineering; Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory; Collaborative Innovation Center for Marine Biomass Fibers, Materials and Textiles of Shandong Province; Qingdao University, Qingdao 266071, China. jliu@qdu.edu.cn.
authors.forename: Jingquan
authors.initials: J
authors.lastname: Liu
mesh_terms: D000438:Alcohols / Q000737:chemistry*; D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D004563:Electrochemistry; D004566:Electrodes; D006108:Graphite / Q000737:chemistry*; D007501:Iron / Q000032:analysis*; D051379:Mice; D057054:Molecular Imaging / Q000379:methods*; D010084:Oxidation-Reduction; D045663:Quantum Dots / Q000737:chemistry* / Q000633:toxicity
chemical_list: D000438:Alcohols; D006108:Graphite; D007501:Iron