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Issue 9, 2012
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Highly sensitive electrochemical detection of proteins using aptamer-coated gold nanoparticles and surface enzyme reactions

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Abstract

A novel electrochemical detection methodology is described for the femtomolar detection of proteins which utilizes both DNA aptamer-functionalized nanoparticles and a surface enzymatic reaction. Immunoglobulin E (IgE) was used as a model protein biomarker, which possesses two distinct epitopes for antibody (anti-IgE) and DNA aptamer binding. A surface sandwich assay format was utilized involving the specific adsorption of IgE onto a gold electrode surface that was pre-modified with a monolayer of aptamer–nanoparticle conjugates followed by the specific interaction of alkaline phosphatase (ALP) conjugated anti-IgE. To clearly demonstrate the signal enhancement associated with nanoparticle use, anodic current measurements of the ALP catalyzed oxidation of the enzyme substrate 4-aminophenylphosphate (APP) were also compared with electrode surfaces upon which the aptamer was directly attached. The detection of an unlabelled protein at concentrations as low as 5 fM is a significant improvement compared to conventional electrochemical-based immunoassay approaches and provides a foundation for the practical use and incorporation of nanoparticle-enhanced detection into electrochemical biosensing technologies.

Graphical abstract: Highly sensitive electrochemical detection of proteins using aptamer-coated gold nanoparticles and surface enzyme reactions

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Article information


Submitted
21 Oct 2011
Accepted
16 Jan 2012
First published
02 Feb 2012

Analyst, 2012,137, 2011-2016
Article type
Communication

Highly sensitive electrochemical detection of proteins using aptamer-coated gold nanoparticles and surface enzyme reactions

E. J. Nam, E. J. Kim, A. W. Wark, S. Rho, H. Kim and H. J. Lee, Analyst, 2012, 137, 2011
DOI: 10.1039/C2AN15994E

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