title: A novel electrochemical immunosensor based on nonenzymatic Ag@Au-Fe3O4 nanoelectrocatalyst for protein biomarker detection.
abstract: A hybrid nanostructure of Fe3O4 nanospheres and Ag@Au nanorods prepared by polydopamine coating was utilized as nanoelectrocatalyst to construct a novel sandwich-type electrochemical immunosensor. Ag@Au-Fe3O4 nanohybrid modified electrode exhibited much better electrocatalytic activity toward the reduction of hydrogen peroxide than Fe3O4 nanospheres or Ag@Au nanorods due to the synergetic catalytic effect. The immunosensor was prepared by immobilizing the capture antibodies on the amine-terminated nanocomposite of carbon nanofibers-chitosan, whilst the trace tag was prepared by loading detection antibodies on the Ag@Au-Fe3O4 nanocomposite. After the parameter optimization, the amperometric signal increased linearly with human IgG concentration in the broad range of 0.1pgmL(-1) to 5μgmL(-1) with a detection limit of 50fgmL(-1). Meanwhile, the enzyme-free catalyst based immunosensor also showed acceptable selectivity, reproducibility and stability.
authors.affiliation: Ministry of Education Key Laboratory of Synthetic and Natural Functional Molecular Chemistry, College of Chemistry and Materials Science, Northwest University, Xi'an 710127, PR China. Electronic address: zhanghf@nwu.edu.cn.
authors.forename: Hongfang
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Ministry of Education Key Laboratory of Synthetic and Natural Functional Molecular Chemistry, College of Chemistry and Materials Science, Northwest University, Xi'an 710127, PR China.
authors.forename: Lina
authors.initials: L
authors.lastname: Ma
authors.affiliation: Ministry of Education Key Laboratory of Synthetic and Natural Functional Molecular Chemistry, College of Chemistry and Materials Science, Northwest University, Xi'an 710127, PR China.
authors.forename: Pengli
authors.initials: P
authors.lastname: Li
authors.affiliation: Shaanxi Provincial Key Laboratory of Electroanalytical Chemistry, Northwest University, Xi'an 710069, PR China.
authors.forename: Jianbin
authors.initials: J
authors.lastname: Zheng
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry*; D015415:Biomarkers / Q000032:analysis; D015374:Biosensing Techniques / Q000379:methods; D002384:Catalysis; D055664:Electrochemical Techniques / Q000379:methods*; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007074:Immunoglobulin G / Q000032:analysis*; D057230:Limit of Detection; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D012834:Silver / Q000737:chemistry*
chemical_list: D055910:Antibodies, Immobilized; D015415:Biomarkers; D007074:Immunoglobulin G; D012834:Silver; D006046:Gold; D052203:Ferrosoferric Oxide
keywords: Ag@Au nanorods; Electrochemical Immunosensor; Fe(3)O(4) nanospheres; Nanoelectrocatalyst