title: Au@Ag nanorods based electrochemical immunoassay for immunoglobulin G with signal enhancement using carbon nanofibers-polyamidoamine dendrimer nanocomposite.
abstract: Au@Ag nanorods (Au@AgNRs) was utilized to construct a novel sandwich-type electrochemical immunosensor for the detection of immunoglobulin G (IgG). The sensor was prepared by immoblizing capture antibodies on the amine-terminated nanocomposite of carbon nanofibers-polyamidoamine dendrimer (CNFs-PAMAM), whilst the trace tag was prepared by loading anti-human IgG on Au@AgNRs. The "built-in" Ag layer on Au nanorods was characterized by UV-vis extinction spectra, transmission electron microscopy and energy dispersive spectroscopy. The results of cyclic voltammetry indicated that modifying CNFs-PAMAM nanocomposite on glassy carbon electrode enabled 177 times of peak current increase of Ag in the bimetallic nanorods. The peak current was quantitatively related with the concentration of the target protein IgG via the formation of immunocomplex. After the parameter optimization, the oxidative peak current of silver was proportional to the concentration of IgG in a wide linear range of six orders of magnitude with a low detection limit of 0.5 fg mL(-1). Besides, this sensor showed acceptable reproducibility and stability, and thus the strategy reported here has great promise for extension to the other disease biomarkers.
authors.affiliation: Ministry of Education Key Laboratory of Synthetic and Natural Functional Molecular Chemistry, College of Chemistry and Materials Science, Northwest University, Xi'an 710069, 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 710069, PR China.
authors.forename: Danlei
authors.initials: D
authors.lastname: Ning
authors.affiliation: Ministry of Education Key Laboratory of Synthetic and Natural Functional Molecular Chemistry, College of Chemistry and Materials Science, Northwest University, Xi'an 710069, PR China. Electronic address: zhanghf@nwu.edu.cn.
authors.forename: Hongfang
authors.initials: H
authors.lastname: Zhang
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: D015374:Biosensing Techniques; D002244:Carbon / Q000737:chemistry; D050091:Dendrimers / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry / Q000302:isolation & purification*; D053768:Metal Nanoparticles / Q000737:chemistry*; D057139:Nanofibers / Q000737:chemistry; D043942:Nanotubes / Q000737:chemistry; D012834:Silver / Q000737:chemistry
chemical_list: D050091:Dendrimers; D007074:Immunoglobulin G; D012834:Silver; D002244:Carbon; D006046:Gold
keywords: Au@Ag nanorods; Carbon nanofibers; Dendrimer; Electrochemical immunosensor; Human immunoglobulin G