Application of impedance spectroscopy for monitoring colloid Au-enhanced antibody immobilization and antibody–antigen reactions

We used colloidal Au to enhance the amount of antibody immobilized on a gold electrode and ultimately monitored the interaction of antigen–antibody by impedance measurement. Self-assembly of 6 nm (diameter) colloidal Au onto the self-assembled monolayers (SAMs) of 4-aminothiophenol modified gold ele...

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Bibliographic Details
Published in:Biosensors & bioelectronics 2004-01, Vol.19 (6), p.575-582
Main Authors: Wang, Meijia, Wang, Lianying, Wang, Gang, Ji, Xiaohui, Bai, Yubai, Li, Tiejin, Gong, Shaoyun, Li, Jinghong
Format: Article
Language:English
Subjects:
Adsorption
Animals
Antibodies - analysis
Antibodies - immunology
Antibodies, Monoclonal - analysis
Antibodies, Monoclonal - immunology
Antibody
Antigen
Antigen-Antibody Complex - analysis
Antigen-Antibody Complex - immunology
Antigen-Antibody Reactions - immunology
Biological and medical sciences
Biosensing Techniques - instrumentation
Biosensing Techniques - methods
Biosensors
Biotechnology
Coated Materials, Biocompatible - chemical synthesis
Colloidal Au
Electric Impedance
Electrochemistry - instrumentation
Electrochemistry - methods
Equipment Design
Equipment Failure Analysis
Fundamental and applied biological sciences. Psychology
Gold Colloid
Hepatitis B Antibodies - analysis
Hepatitis B Antibodies - immunology
Hepatitis B virus
Immunoassay - instrumentation
Immunoassay - methods
Impedance spectroscopy
Methods. Procedures. Technologies
Mice
Reproducibility of Results
Self-assembly
Sensitivity and Specificity
Spectrum Analysis - instrumentation
Spectrum Analysis - methods
Various methods and equipments
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Summary:We used colloidal Au to enhance the amount of antibody immobilized on a gold electrode and ultimately monitored the interaction of antigen–antibody by impedance measurement. Self-assembly of 6 nm (diameter) colloidal Au onto the self-assembled monolayers (SAMs) of 4-aminothiophenol modified gold electrode resulted in an easier attachment of antibody. The redox reactions of [Fe(CN) 6] 4−/[Fe(CN) 6] 3− on the gold surface were blocked due to the procedures of self-assembly of 4-aminothiophenol and antibody immobilization, which were investigated by cyclic voltammetry and impedance spectroscopy. The interaction of antigen with grafted antibody recognition layers was carried out by soaking the modified electrode into a phosphate buffer at pH 7.4 with various concentrations of antigen at 37 °C for 30 min. The antibody recognition layers and their interactions with various concentrations of antigen could be detected by measurements of the impedance change. The results show that this method has good correlation for detection of Hepatitis B virus surface antigen in the range of 0.5–200 μg/l and a detection limit of about 50 ng/l.
ISSN:0956-5663
1873-4235
DOI:10.1016/S0956-5663(03)00252-5