title: Nanogold-enhanced graphene nanosheets as multienzyme assembly for sensitive detection of low-abundance proteins.
abstract: A new electrochemical immunosensing protocol was designed for detection of carcinoembryonic antigen (CEA, as a model protein) by using graphene-carried poly(o-phenylenediamine)/gold hybrid nanosheets (GNPGs) as signal tags on the hierarchical dendritic gold microstructures (HDGMs)-modified glassy carbon electrode. To prepare the signal tags, poly(o-phenylenediamine) molecules were initially immobilized on the surface of graphene nanosheets via the π-stacking interaction. Then gold nanoparticles were assembled onto the poly(o-phenylenediamine)-modified graphene nanosheets, which were used for the labeling of anti-CEA detection antibodies and horseradish peroxidase (HRP). The as-prepared GNPGs were characterized by using atomic force microscopy (AFM), transmission electron microscopy (TEM) and UV-vis absorption spectroscopy. The assay was carried out with a sandwich-type immunoassay format in pH 5.5 acetic acid-buffered saline solutions containing 2.5 mmol L(-1) H2O2. Under optimal conditions, the electrochemical immunoassay exhibited a wide dynamic range of 0.005-80 ng mL(-1) toward CEA standards with a low detection limit of 5.0 pg mL(-1). Intra- and inter-assay coefficients of variation were less than 11.5%. No significant difference at the 0.05 significance level was encountered in the analysis of 6 clinical serum specimens and 6 spiked blank new born cattle serum specimens between the developed immunoassay and commercially available electrochemiluminescent (ECL) method for the detection of CEA.
authors: Key Laboratory of Analysis and Detection for Food Safety (Ministry of Education and Fujian Province), Department of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350108, PR China.
authors: Huafeng
authors: H
authors: Chen
authors: Zhuangqiang
authors: Z
authors: Gao
authors: Yuling
authors: Y
authors: Cui
authors: Guonan
authors: G
authors: Chen
authors: Dianping
authors: D
authors: Tang
mesh_terms: D000818:Animals; D002272:Carcinoembryonic Antigen / Q000097:blood*; D002417:Cattle; D055664:Electrochemical Techniques / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay / Q000379:methods; D057230:Limit of Detection; D049329:Nanostructures / Q000737:chemistry*; D010084:Oxidation-Reduction; D010655:Phenylenediamines / Q000737:chemistry
chemical_list: D002272:Carcinoembryonic Antigen; D010655:Phenylenediamines; C530487:poly(o-phenylenediamine); D006046:Gold; D006108:Graphite