title: Novel signal amplification strategy for ultrasensitive sandwich-type electrochemical immunosensor employing Pd-Fe3O4-GS as the matrix and SiO2 as the label.
abstract: An ultrasensitive sandwich-type electrochemical immunosensor based on a novel signal amplification strategy was developed for the quantitative determination of human immunoglobulin G (IgG). Pd nanocubes functionalized magnetic graphene sheet (Pd-Fe3O4-GS) was employed as the matrix to immobilize the primary antibodies (Ab1). Owing to the synergetic effect between Pd nanocubes and magnetic graphene sheet (Fe3O4-GS), Pd-Fe3O4-GS can provide an obviously increasing electrochemical signal by electrochemical catalysis towards hydrogen peroxide (H2O2). Silicon dioxide (SiO2) was functionalized as the label to conjugate with the secondary antibodies (Ab2). Due to the larger steric hindrance of the obtained conjugate (SiO2@Ab2), the sensitive decrease of the electrochemical signal can be achieved after the specific recognition between antibodies and antigens. In this sense, this proposed immunosensor can achieve a high sensitivity, especially in the presence of low concentrations of IgG. Under optimum conditions, the proposed immunosensor offered an ultrasensitive and specific determination of IgG down to 3.2 fg/mL. This immunoassay method would open up a new promising platform to detect various tumor markers at ultralow levels for early diagnoses of different cancers.
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: Yulan
authors.initials: Y
authors.lastname: Wang
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: Hongmin
authors.initials: H
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: Xiaodong
authors.initials: X
authors.lastname: Wang
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: Xuehui
authors.initials: X
authors.lastname: Pang
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: Dan
authors.initials: D
authors.lastname: Wu
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: Bin
authors.initials: B
authors.lastname: Du
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: sdjndxwq@163.com.
authors.forename: Qin
authors.initials: Q
authors.lastname: Wei
mesh_terms: D055664:Electrochemical Techniques / Q000379:methods*; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007074:Immunoglobulin G / Q000097:blood*; D057230:Limit of Detection; D008958:Models, Molecular; D010165:Palladium / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D007074:Immunoglobulin G; D010165:Palladium; D012822:Silicon Dioxide; D006108:Graphite; D052203:Ferrosoferric Oxide
keywords: Human immunoglobulin G; Pd–Fe(3)O(4)-GS; Sandwich-type electrochemical immunosensor; SiO(2); Tumor markers