title: Graphene-palladium nanowires based electrochemical sensor using ZnFe2O4-graphene quantum dots as an effective peroxidase mimic.
abstract: We proposed an electrochemical DNA sensor by using peroxidase-like magnetic ZnFe2O4-graphene quantum dots (ZnFe2O4/GQDs) nanohybrid as a mimic enzymatic label. Aminated graphene and Pd nanowires were successively modified on glassy carbon electrode, which improved the electronic transfer rate as well as increased the amount of immobilized capture ssDNA (S1). The nanohybrid ZnFe2O4/GQDs was prepared by assembling the GQDs on the surface of ZnFe2O4 through a photo-Fenton reaction, which was not only used as a mimic enzyme but also as a carrier to label complementary ssDNA (S3). By synergistically integrating highly catalytically activity of nano-sized GQDs and ZnFe2O4, the nanohybrid possessed highly-efficient peroxidase-like catalytic activity which could produce a large current toward the reduction of H2O2 for signal amplification. Thionine was used as an excellent electron mediator. Compared with traditional enzyme labels, the mimic enzyme ZnFe2O4/GQDs exhibited many advantages such as environment friendly and better stability. Under the optimal conditions, the approach provided a wide linear range from 10(-16) to 5×10(-9) M and low detection limit of 6.2×10(-17) M. The remarkable high catalytic capability could allow the nanohybrid to replace conventional peroxidase-based assay systems. The new, robust and convenient assay systems can be widely utilized for the identification of other target molecules.
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China.
authors.forename: Weiyan
authors.initials: W
authors.lastname: Liu
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Yang
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China.
authors.forename: Chao
authors.initials: C
authors.lastname: Ma
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China.
authors.forename: Ya-nan
authors.initials: YN
authors.lastname: Ding
authors.affiliation: Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials, University of Jinan, Jinan 250022, PR China.
authors.forename: Shenguang
authors.initials: S
authors.lastname: Ge
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China.
authors.forename: Jinghua
authors.initials: J
authors.lastname: Yu
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China. Electronic address: chm_yanm@126.com.
authors.forename: Mei
authors.initials: M
authors.lastname: Yan
mesh_terms: D015374:Biosensing Techniques / Q000379:methods; D004247:DNA / Q000032:analysis* / Q000097:blood; D055664:Electrochemical Techniques / Q000379:methods; D005290:Ferric Compounds / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D057230:Limit of Detection; D059346:Magnets / Q000737:chemistry*; D053770:Nanowires / Q000737:chemistry* / Q000648:ultrastructure; D010165:Palladium / Q000737:chemistry*; D009195:Peroxidase / Q000737:chemistry; D045663:Quantum Dots / Q000737:chemistry* / Q000648:ultrastructure; D015032:Zinc / Q000737:chemistry
chemical_list: D005290:Ferric Compounds; C001215:ferrite; D010165:Palladium; D006108:Graphite; D004247:DNA; D006861:Hydrogen Peroxide; D009195:Peroxidase; D015032:Zinc
keywords: Electrochemical sensor; Mimic enzymes; Palladium nanowires; ZnFe(2)O(4)–graphene quantum dots composites