An ultrasensitive label-free electrochemical immunosensor based on signal amplification strategy of multifunctional magnetic graphene loaded with cadmium ions

作者：Li, Faying; Li, Yueyun^*; Dong, Yunhui; Jiang, Liping; Wang, Ping; Liu, Qing; Liu, Hui; Wei, Qin^*

来源：Scientific Reports, 2016, 6(1): 21281.

DOI：10.1038/srep21281

• AU NANOPARTICLES
• IMMUNOGLOBULIN-G
• IMMUNOASSAY
• ELECTROCHEMILUMINESCENCE
• COMPOSITE
• SPECTROSCOPY
• NANOCHAINS
• CATALYSIS
• PLATFORM
• MATRIX

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 (Cd2+) 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/Cd2+) 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/Cd2+, 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.

• 出版日期2016-2-16
• 单位山东理工大学; 山东大学; 济南大学