title: An ultrasensitive label-free electrochemical immunosensor based on signal amplification strategy of multifunctional magnetic graphene loaded with cadmium ions.
abstract: Herein, a novel and ultrasensitive label-free electrochemical immunosensor was proposed for quantitative detection of human Immunoglobulin G (IgG). The amino functionalized magnetic graphenes nanocomposites (NH2-GS-Fe3O4) were prepared to bond gold and silver core-shell nanoparticles (Au@Ag NPs) by constructing stable Au-N and Ag-N bond between Au@Ag NPs and -NH2. Subsequently, the Au@Ag/GS-Fe3O4 was applied to absorb cadmium ion (Cd(2+)) due to the large surface area, high conductivity and exceptional adsorption capability. The functional nanocomposites of gold and silver core-shell magnetic graphene loaded with cadmium ion (Au@Ag/GS-Fe3O4/Cd(2+)) can not only increase the electrocatalytic activity towards hydrogen peroxide (H2O2) but also improve the effective immobilization of antibodies because of synergistic effect presented in Au@Ag/GS-Fe3O4/Cd(2+), which greatly extended the scope of detection. Under the optimal conditions, the proposed immunosensor was used for the detection of IgG with good linear relation in the range from 5 fg/mL to 50 ng/mL with a low detection limit of 2 fg/mL (S/N = 3). Furthermore, the proposed immunosensor showed high sensitivity, special selectivity and long-term stability, which had promising application in bioassay analysis.
authors.affiliation: School of Chemical Engineering, Shandong University of Technology, Zibo, 255049, P.R. China.
authors.forename: Faying
authors.initials: F
authors.lastname: Li
authors.affiliation: School of Chemical Engineering, Shandong University of Technology, Zibo, 255049, P.R. China.|Key Laboratory of Chemical Sensing &Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan, 250022, P.R. China.
authors.forename: Yueyun
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Chemical Engineering, Shandong University of Technology, Zibo, 255049, P.R. China.
authors.forename: Yunhui
authors.initials: Y
authors.lastname: Dong
authors.affiliation: School of Chemical Engineering, Shandong University of Technology, Zibo, 255049, P.R. China.
authors.forename: Liping
authors.initials: L
authors.lastname: Jiang
authors.affiliation: School of Chemical Engineering, Shandong University of Technology, Zibo, 255049, P.R. China.
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.affiliation: School of Chemical Engineering, Shandong University of Technology, Zibo, 255049, P.R. China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Liu
authors.affiliation: School of Chemical Engineering, Shandong University of Technology, Zibo, 255049, P.R. China.
authors.forename: Hui
authors.initials: H
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, P.R. China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Wei
mesh_terms: D055910:Antibodies, Immobilized; D015374:Biosensing Techniques; D002104:Cadmium / Q000737:chemistry; D055664:Electrochemical Techniques; D006108:Graphite / Q000737:chemistry; D007074:Immunoglobulin G; D007477:Ions; D058185:Magnetite Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D015203:Reproducibility of Results
chemical_list: D055910:Antibodies, Immobilized; D007074:Immunoglobulin G; D007477:Ions; D058185:Magnetite Nanoparticles; D002104:Cadmium; D006108:Graphite