Chip-Based Measurements of Brownian Relaxation of Magnetic Beads Using a Planar Hall Effect Magnetic Field Sensor

Frederik Westergaard Østerberg, Bjarke Thomas Dalslet, Detlef Snakenborg, Christer Johansson, Mikkel Fougt Hansen

    Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

    Abstract

    We present a simple 'click-on' fluidic system with integrated electrical contacts, which is suited for electrical measurements on chips in microfluidic systems. We show that microscopic magnetic field sensors based on the planar Hall effect can be used for detecting the complex magnetic response using only the self-field arising from the bias current applied to the sensors as excitation field. We present measurements on a suspension of magnetic beads with a nominal diameter of 250 nm vs. temperature and find that the observations are consistent with the Cole-Cole model for Brownian relaxation with a constant hydrodynamic bead diameter when the temperature dependence of the viscosity of water is taken into account. These measurements demonstrate the feasibility of performing measurements of the Brownian relaxation response in a lab-on-a-chip system and constitute the first step towards an integrated biosensor based on the detection of the dynamic response of magnetic beads.
    Original languageEnglish
    Title of host publication8. INTERNATIONAL CONFERENCE ON THE SCIENTIFIC AND CLINICAL APPLICATIONS OF MAGNETIC CARRIERS
    Publication date2010
    Pages176-183
    Publication statusPublished - 2010
    Event8. International Conference on the Scientific and Clinical Applications of Magnetic Carriers - Rostock, GERMANY
    Duration: 1 Jan 2010 → …
    Conference number: 8

    Conference

    Conference8. International Conference on the Scientific and Clinical Applications of Magnetic Carriers
    Number8
    CityRostock, GERMANY
    Period01/01/2010 → …
    SeriesAip Conference Proceedings
    Number1311
    ISSN0094-243X

    Keywords

    • Magnetorelaxometry
    • Lab-on-a-chip
    • Brownian relaxation
    • Planar Hall effect

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