Electrochemical immunosensor for human chorionic gonadotropin based on horseradish peroxidase–functionalized Prussian blue–carbon nanotubes/gold nanocomposites as labels for signal amplification

• Published in: Electrochimica acta Vol. 56; no. 5; pp. 1973 - 1980
• Main Authors: Yang, Hongchuan, Yuan, Ruo, Chai, Yaqin, Su, Huilan, Zhuo, Ying, Jiang, Wen, Song, Zhongju
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.02.2011; Elsevier
• Subjects: Amplification; Antibodies; Biological and medical sciences; Biosensors; Biotechnology; Carbon nanotubes; Electrochemical immunosensor; Enzyme amplification; Fundamental and applied biological sciences. Psychology; Gold; Human; Human chorionic gonadotropin; Investigative techniques, diagnostic techniques (general aspects); Labels; Medical sciences; Methods. Procedures. Technologies; Miscellaneous. Technology; Nanocomposites; Nanotubes; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Prussian blue; Titanium dioxide; Various methods and equipments; Carbon nanotubes; Electrochemical immunosensor; Prussian blue; Human chorionic gonadotropin; Enzyme amplification; Titanium IV Oxides; Biological fluid; Chemical analysis; Immobilization; Immunosensor; Composite material; Blood; Electrodes; Electrochemicalimmunosensor; Protein hormone; Clinical biology; Chorionic gonadotrophin; Nanocomposite; Peroxidase; Iron III Hexacyanoferrates; Quantitative analysis; Modified material; Human; Urine; Gold; Enzyme; Antibody; Transition metal; Nanostructure; Carbon; Peroxidases; Biosensor; Oxidoreductases; Chitosan; Hydrogel; Blood serum; Polysaccharide; Glassy state
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2010.12.003

A new strategy for the sensitive detection of biomarker using Prussian blue–carbon nanotubes/gold nanocomposites (GNPs–PB–CNTs) as labels and horseradish peroxidase (HRP) as an enhancer is presented herein. Chitosan hydrogel and TiO2 nanocomposites were first coated onto a glassy carbon electrode (GCE) surface, which provided a biocompatible interface with abundant –NH2 groups for the immobilization of primary antibodies (Ab1). The detectable signal was recorded and amplified based on a sandwich-type immunoassay by the employment of HRP-labeled secondary antibodies (HRP-Ab2) and GNPs–PB–CNTs bioconjugates according to the electrocatalytic reduction of H2O2 by bound HRP in the presence of PB. Using human chorionic gonadotropin (HCG) as a model analyte, experimental results showed that the prepared HRP-Ab2–GNPs–PB–CNTs bioconjugates exhibited satisfactory redox activity and high efficiency of enzyme catalysis. Under optimized conditions, the immunosensor showed a low detection limit of 0.023mIU/mL HCG, with a linear range from 0.05 to 150mIU/mL. The proposed method exhibited high sensitivity, acceptable stability and reproducibility, and could be extended to detect other protein targets.