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.

SUBMITTER: Li F 

PROVIDER: S-EPMC4754691 | biostudies-literature | 2016 Feb

REPOSITORIES: biostudies-literature