A Direct Competitive Homogeneous Immunoassay for Progesterone – the Redox Quenching Immunoassay |
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Authors: | Julia Ettlinger Jörg A Schenk Burkhard Micheel Eva Ehrentreich‐Förster Nenad Gajovic‐Eichelmann |
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Institution: | 1. Fraunhofer Institute for Biomedical Engineering, Am Muhlenberg 13, 14476 Potsdam, Germany;2. Hybrotec GmbH, Am Muhlenberg 11, 14476 Potsdam, Germany;3. University of Potsdam, Karl‐Liebknecht Str. 25, 14476 Potsdam, Germany |
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Abstract: | A direct competitive amperometric immunoassay format for the detection of haptens and proteins was developed. The method is based on the quenching of electroactivity of ferrocenium, which is coupled to the antigen and used as the primary reporter, upon binding to a monoclonal anti‐ferrocenium antibody, which is coupled to the detection antibody and used as a secondary reporter. A separation‐free progesterone immunoassay with a lower detection limit of 1 ng mL?1 (3.18 nmol L?1) in 1 : 2 diluted blood serum was realised by combining two bifunctional conjugates, a ferrocenium‐PEG‐progesterone tracer and a bioconjugate of one anti‐progesterone and one anti‐ferrocenium antibody. The immune complex is formed within 30 s upon addition of progesterone, resulting in a total analysis time of 1.5 min. |
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Keywords: | Immunoassay Amperometry Ferrocene Progesterone |
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