The Impact of Antibody/Epitope Affinity Strength on the Sensitivity of Electrochemical Immunosensors for Detecting Small Molecules

Anal Bioanal Chem 405 (2013) 3889–3898, 2013

10 Pages Posted: 11 Jul 2017

See all articles by Sook Mei Khor

Sook Mei Khor

University of Malaya (UM) - Department of Chemistry

Pall Thordarson

University of New South Wales (UNSW) - School of Chemistry and Australian Centre for NanoMedicine

J. Gooding

University of New South Wales (UNSW)

Date Written: February 27, 2013

Abstract

A displacement immunoassay involves having a labelled analogue of the analyte (the epitope) already bound to the antibody. The presence of the analyte causes a competition for antibodies, and some of the antibodies dissociates from the epitope so that it can bind with the analyte. Herein, the influence of the affinity of the surface-bound epitope for the antibody on the sensitivity and selectivity of a displacement immunosensor is explored both theoretically and experimentally. An electrochemical immunosensor described previously [1], where the dissociation of antibodies from an electrode surface causes an increase in current from surface-bound ferrocene species, is used for this purpose. As expected, the ease and effectiveness of the bound antibody being displaced is inversely related to the affinity of the antibody to the surface-bound epitope relative to the analyte in solution as expected. However, if the affinity constant is too low, selectivity and/or sensitivity are compromised. Experimental results are qualitatively compared with a simple mass-action model.

Keywords: Immunosensor, Displacement assay, Electrochemistry, Theory

JEL Classification: I1, I10

Suggested Citation

Khor, Sook Mei and Thordarson, Pall and Gooding, J., The Impact of Antibody/Epitope Affinity Strength on the Sensitivity of Electrochemical Immunosensors for Detecting Small Molecules (February 27, 2013). Anal Bioanal Chem 405 (2013) 3889–3898, 2013. Available at SSRN: https://ssrn.com/abstract=2712107

Sook Mei Khor (Contact Author)

University of Malaya (UM) - Department of Chemistry ( email )

Kuala Lumpur, Wilayah Persekutuan 50603
Kuala Lumpur, Wilayah Persekutuan 50603
Malaysia

Pall Thordarson

University of New South Wales (UNSW) - School of Chemistry and Australian Centre for NanoMedicine

Australia

J. Gooding

University of New South Wales (UNSW) ( email )

Kensington
High St
Sydney, NSW 2052
Australia

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