title: Electrochemical antioxidant detection technique based on guanine-bonded graphene and magnetic nanoparticles composite materials.
abstract: An antioxidant (AO) amperometric technique based on guanine attached to graphene and Fe(3)O(4) nanoparticles (NPs) magnetic materials was developed. Guanine molecules acted as an antioxidant competitor were bonded with graphene nanosheets, onto which magnetic Fe(3)O(4) NPs were attached and the as-prepared magnetic composite can be attracted to the electrode surface by an external magnetic field. When applied with negative potentials, the dissolved oxygen was reduced to H(2)O(2) at the electrode surface, and then reacted with the EDTA-Fe(ii) complex via a Fenton-like reaction to produce OH radicals. After oxidation damage by OH radicals, the electrochemical oxidation of guanine gave a decreased current. In the presence of AOs, the reactive oxygen species (ROS, e.g. OH radicals and H(2)O(2)) were scavenged by AOs and fewer guanine probe molecules were oxidized, thus inducing a higher electrochemical oxidation current of guanine. So AOs competed with the guanine probe molecules toward oxidation by ROS. The current signals of the guanine probe molecules were proportional to the concentrations of AOs. A kinetic model was proposed to quantify the ROS scavenging capacities of the AOs. Using guanine as an oxidizable probe and OH radicals and H(2)O(2) as endogenous ROS, this kind of AO detection technique mimicks the antioxidant protection mechanism by small AO molecules in the human body.
authors.affiliation: Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, Department of Chemistry, Liaocheng University, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Jingjing
authors.initials: J
authors.lastname: Zhao
authors.forename: Fanjun
authors.initials: F
authors.lastname: Meng
authors.forename: Qiaoli
authors.initials: Q
authors.lastname: Yue
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Haibo
authors.initials: H
authors.lastname: Li
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Gu
authors.forename: Shuqiu
authors.initials: S
authors.lastname: Zhang
authors.forename: Jifeng
authors.initials: J
authors.lastname: Liu
mesh_terms: D000975:Antioxidants / Q000032:analysis* / Q000737:chemistry; D015374:Biosensing Techniques; D055664:Electrochemical Techniques; D005290:Ferric Compounds; D006108:Graphite / Q000737:chemistry*; D006147:Guanine / Q000737:chemistry*; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry; D060526:Magnetic Fields; D053768:Metal Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry
chemical_list: D000975:Antioxidants; D005290:Ferric Compounds; C000499:ferric oxide; D017665:Hydroxyl Radical; D006147:Guanine; D006108:Graphite; D006861:Hydrogen Peroxide; D010100:Oxygen