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Issue 4, 2007
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An impedimetric immunosensor for the detection of autoantibodies directed against gliadins

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Abstract

An immunosensor has been developed for the detection of autoantibodies directed against wheat gliadin, a protein fraction of cereal gluten which is involved in celiac disease. The immunosensor is based on the immobilization of gliadins onto gold electrodes covered with a polyelectrolyte layer of poly(4-styrenesulfonic acid sodium salt). The immobilization was monitored by quartz crystal microbalance (QCM) analysis. The antigen–antibody interaction signal was amplified by an incubation step with peroxidase-labeled immunoglobulins and subsequent peroxidase-catalyzed oxidation of 3-amino-9-ethylcarbazole (AEC). Changes in the insulating properties of the electrode layer were measured by electrochemical impedance spectroscopy (EIS) in the presence of ferri/ferro-cyanide. Impedance spectra could be fitted to a Randles equivalent circuit with high accuracy. Exposing the sensor electrodes to various antigliadin antibody concentrations resulted in proportional changes in the charge transfer resistance. A calibration graph for the detection of antigliadin antibodies was established for antibody concentrations between 10−8 and 10−6 M. Finally, the sensor was used for the determination of antigliadin autoantibodies of the IgG and IgA type in several human sera.

Graphical abstract: An impedimetric immunosensor for the detection of autoantibodies directed against gliadins

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Publication details

The article was received on 10 Jul 2006, accepted on 18 Jan 2007 and first published on 09 Feb 2007


Article type: Paper
DOI: 10.1039/B609832K
Citation: Analyst, 2007,132, 314-322
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    An impedimetric immunosensor for the detection of autoantibodies directed against gliadins

    T. Balkenhohl and F. Lisdat, Analyst, 2007, 132, 314
    DOI: 10.1039/B609832K

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