C. Kohn

University of Freiburg, Freiburg, Baden-Württemberg, Germany

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Publications (2)0 Total impact

  • I. Moser · B. Enderle · C. Kohn · G. Jobst · G. Urban
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    ABSTRACT: A foil-based BioMEMS for electrochemical capillary immunoassay for hepatitis serology is presented. Immobilization of the hepatitis antigen utilizing capillary forces and special stopping barriers in foil based microsystems and the application of it in fast immunoassays will be shown. The measurement starts with the addition of the antibody containing human serum sample. Subsequently the signal antibody labelled with glucose oxidase binds to the hepatitis B antibody and converts glucose to hydrogen peroxide, which is oxidized at the electrode in the measurement cell. The assay is very sensitive and designed to differentiate between hepatitis B negative (below 10 U/l) and positive serum. The present limit of detection of immunoassays in the BioMEMS is 20 atto-moles.
    No preview · Conference Paper · Jul 2005
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    ABSTRACT: For the first time, we present a simple and robust optical concept to enable precise and sensitive read-out of colorimetric assays in flat lab-on-a-chip devices. The optical guidance of the probe beam through an incorporated measurement chamber to the detector is based on the total internal reflection at V-grooves in the polymer chip. This way, the optical path length through the flat measurement chamber and thus the performance of the measurements are massively enhanced compared to direct (perpendicular) beam incidence. This is demonstrated by a chip-based, colorimetric glucose-assay on serum. Outstanding features are an excellent reproducibility (CV= 1.91 %), a competitive lower limit of detection (c<sub>min</sub> = 124 μM), and a high degree of linearity (R<sup>2</sup> = 0.998) within a working range extending over nearly three orders of magnitude.
    Full-text · Conference Paper · Jan 2005