Hradetzky, David

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Hradetzky
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David
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Hradetzky, David

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2001 - 20098
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Enddatum: 2009 × Anfangsdatum: 2001 ×

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  • Vorschaubild nicht verfügbar
    Publikation
    Capacitive on-line hematocrit sensor design based on impedance spectroscopy for use in hemodialysis machines
    (IEEE, 2009) Trebbels, D.; Hradetzky, David; Zengerle, R. [in: 2009 annual international conference of the IEEE engineering in medicine and biology society]
    This paper presents a new design for an on-line and in-line hematocrit (HCT) sensor. Special feature of the sensor is the capability to measure the hematocrit of a blood sample inside standard plastic tubing widely used in medical equipment. No blood sample has to be extracted out of existing extracorporeal blood circulation systems such as hemodialysis machines or heart-lung machines. The sensor principle is based on electrical impedance spectroscopy. Dielectric properties of the blood and the plastic tubing are measured at various frequencies. In order to optimize the sensitivity, a unique electrode configuration is developed and optimized by Finite Element Simulation. The new electrode design optimizes the overall sensitivity of the sensor towards a change in dielectric properties of the blood caused by the HCT value and therefore decreases the sensitivity to side effects caused by temperature drift and component tolerances. As a result of the optimized overall sensor performance the complexity of a sensor readout circuitry can be reduced to a minimum which leads to an unmatched price-performance ratio for a complete measurement system.
    04B - Beitrag Konferenzschrift
  • Vorschaubild nicht verfügbar
    Publikation
    Hematocrit measurement - a high precision on-line measurement system based on impedance spectroscopy for use in hemodialysis machines
    (2009) Trebbels, Dennis; Zengerle, Roland; Hradetzky, David [in: IFMBE Proceedings]
    This paper presents a unique technical approach to measure the proportion of blood volume occupied by red blood cells, the hematocrit value (HCT) on-line and in-line. A practical method has been developed to measure without the need for extracting blood samples out of an existing extracorporeal blood circulation system. The new sensor is based on Impedance Spectroscopy and measures electrical properties of the blood at various frequencies. In order to achieve the required precision resolution the sensor geometry has been optimized by Finite Element Analysis. For sensor readout a digital measurement circuitry based on cheap standard components is developed and allows practical implementation of HCT-sensor devices for the first time. Special care has been taken in order to compensate for the temperature effects.
    04B - Beitrag Konferenzschrift
  • Vorschaubild nicht verfügbar
    Publikation
    Eye-Cam: Sprachgesteuerte Miniaturkamera integriert in einer Brille
    (2007) Hradetzky, David; Kliche, Kurt; Ehrbrecht, Bernd; Anka, Laszlo; Wölfle, Matthias; Zengerle, Roland [in: VDE: Proceedings]
    04B - Beitrag Konferenzschrift
  • Vorschaubild nicht verfügbar
    Publikation
    Interferometric label-free biomolecular detection system
    (IOP Publishing Ltd, 2006) Hradetzky, David; Mueller, Claas; Reinecke, Holger [in: Journal of Optics A: Pure and Applied Optics]
    This work presents a simple evanescent wave sensing system based on an interferometric approach, suitable to meet the requirements of label-free sensor systems for detecting biomolecular interactions. It represents a basic concept towards label-free detection systems in various applications. The basic objectives of transducers for evanescent wave sensing are discussed. An optical detection system based on a interferometric approach using Young's double slit configuration is discussed, set-up and characterized. With refractometric measurements of various sucrose dilutions, the performance of the pure optical set-up is evaluated.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild nicht verfügbar
    Publikation
    Interferometric sensor platform for biomolecular interaction analysis
    (VDE, 2005) Hradetzky, David; Müller, Claas; Reinecke, Holger [in: Mikrosystemtechnik-Kongress 2005]
    04B - Beitrag Konferenzschrift
  • Vorschaubild nicht verfügbar
    Publikation
    02 - Monographie
  • Vorschaubild nicht verfügbar
    Publikation
    Label free detection of biomolecular interactions
    (IEEE, 2005) Hradetzky, David; Müller, Claas; Reinecke, Holger [in: IEEE/LEOS International Conference on Optical MEMS and Their Applications Conference, 2005.]
    This work presents a simple evanescent wave sensing system based on an interferometric approach suitable to meet the demands on label free sensor systems for the detection of biomolecular interactions especially. It is representing a basic concept towards high throughput application. The system performance and reproducibility was evaluated with refractometric measurements of sucrose dilutions. A mean resolution of the effective refractive index of 3sigma(Deltamacrnmacr eff )=0.9middot10 -6 without averaging and a reproducibility below sigma r =0.1middot10 -6 were achieved. The suitability for the detection of biomolecular interactions was validated with the detection of a DNA hybridization
    04B - Beitrag Konferenzschrift
  • Vorschaubild nicht verfügbar
    Publikation
    Interferometrisches Biosensor System
    (2001) Wikerstål, Andreas; Brandenburg, Albrecht; Hradetzky, David; Krauter, Ralf; Künzel, Christa; Schulte, Heinrich; Stefan, Monika
    04B - Beitrag Konferenzschrift