Highly Sensitive Photoelectrochemical Immunoassay with Enhanced Amplification Using Horseradish Peroxidase Induced Biocatalytic Precipitation on a CdS Quantum Dots Multilayer Electrode

Herein we demonstrate the protocol of a biocatalytic precipitation (BCP)-based sandwich photoelectrochemical (PEC) horseradish peroxidase (HRP)-linked immunoassay on the basis of their synergy effect for the ultrasensitive detection of mouse IgG (antigen, Ag) as a model protein. The hybrid film cons...

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Bibliographic Details
Published in:Analytical chemistry (Washington) 2012-01, Vol.84 (2), p.917-923
Main Authors: Zhao, Wei-Wei, Ma, Zheng-Yuan, Yu, Pei-Pei, Dong, Xiao-Ya, Xu, Jing-Juan, Chen, Hong-Yuan
Format: Article
Language:English
Subjects:
Analytical chemistry
Animals
Antibodies, Monoclonal - immunology
Antigens
Biocatalysis
Biosensing Techniques - instrumentation
Cadmium Compounds - chemistry
Chemical precipitation
Chemistry
Electrochemistry
Electrodes
Exact sciences and technology
Gold
Horseradish Peroxidase - metabolism
Immunoassay
Immunoassay - instrumentation
Immunoglobulin G - analysis
Immunoglobulins
Limit of Detection
Mice
Miscellaneous
Photometry - instrumentation
Quantum Dots
Rodents
Sulfides - chemistry
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Summary:Herein we demonstrate the protocol of a biocatalytic precipitation (BCP)-based sandwich photoelectrochemical (PEC) horseradish peroxidase (HRP)-linked immunoassay on the basis of their synergy effect for the ultrasensitive detection of mouse IgG (antigen, Ag) as a model protein. The hybrid film consisting of oppositely charged polyelectrolytes and CdS quantum dots (QDs) is developed by the classic layer by layer (LbL) method and then employed as the photoactive antibody (Ab) immobilization matrix for the subsequent sandwich-type Ab-Ag affinity interactions. Improved sensitivity is achieved through using the bioconjugates of HRP-secondary antibodies (Ab2). In addition to the much enhanced steric hindrance compared with the original one, the presence of HRP would further stimulate the BCP onto the electrode surface for signal amplification, concomitant to a competitive nonproductive absorption that lowers the photocurrent intensity. As a result of the multisignal amplification in this HRP catalyzed BCP-based PEC immunoassay, it possesses excellent analytical performance. The antigen could be detected from 0.5 pg/mL to 5.0 ng/mL with a detection limit of 0.5 pg/mL.
ISSN:0003-2700
1520-6882
DOI:10.1021/ac203184g