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AC susceptometry and magnetorelaxometry for magnetic nanoparticle based biomolecule detection

  • D. EberbeckEmail author
  • A. P. Astalan
  • K. Petersson
  • F. Wiekhorst
  • C. Bergemann
  • C. Johansson
  • U. Steinhoff
  • H. Richter
  • A. Krozer
  • L. Trahms
Conference paper
Part of the IFMBE Proceedings book series (IFMBE, volume 22)

Abstract

Functionalized magnetic nanoparticles are increasingly used as probes in biomolecule detection. We compared two different techniques, which provide information on the state of the magnetic particle system. The dynamics of an ensemble of magnetic nanoparticles was probed measuring the response its magnetisation both on an alternating magnetic field by AC-susceptometry and on a jump of external magnetic field by magnetorelaxometry. In order to compare both techniques, we studied the binding of streptavidin functionalized nanoparticles (fluidMAG/BC-SAV) to biotin-agarose beads and to biotinylated prostate specific antigens (PSA-10). By both techniques we observed specific changes in shape and amplitude of the characteristic signals due the binding of the particles. Therewith the signals of bound and unbound probes can be discriminated and a homogeneous assay without time-comsuming washing steps is realized. The AC susceptometry method provides a robust and sensitive measurement technology. Magnetorelaxometry, utilizing superconducting quantum interference devices (SQUIDs) as magnetic field sensors, owns a much shorter measurement time and has the potential of an even higher sensitivity, at the expense of a considerably increased technological effort.

Keywords

magnetic nanoparticles magnetic immunoassay AC susceptometry magnetorelaxometry 

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References

  1. 1.
    Alexiou C, Jurgons R, Seliger C, et al. (2006) Medical Applications of Magnetic Nanoparticles. J Nanosci Nanotech 6:2762–2768CrossRefGoogle Scholar
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    Eberbeck D, Bergemann C, Wiekhorst F, et al. (2008) Quantification of specific bindings of biomolecules by magnetorelaxometry. J Nanobiotechnology 6:4 DOI 10.1186/1477-3155-6-4CrossRefGoogle Scholar
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    Astalan AP, Ahrentorp F, Johansson C, et al. (2004) Biomolecular reactions studied using changes in Brownian rotation dynamics of magnetic particles. Biosensors and Bioelectronics 19:945–951CrossRefGoogle Scholar
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    Eberbeck D, Wiekhorst F, Steinhoff U, et al. (2006) Aggregation behaviour of magnetic nanoparticle suspensions investigated by magnetorelaxometry. J Phys: Cond Matter 18:2829–2846CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  • D. Eberbeck
    • 2
    Email author
  • A. P. Astalan
    • 1
  • K. Petersson
    • 1
  • F. Wiekhorst
    • 2
  • C. Bergemann
    • 3
  • C. Johansson
    • 1
  • U. Steinhoff
    • 2
  • H. Richter
    • 2
  • A. Krozer
    • 1
  • L. Trahms
    • 2
  1. 1.IMEGO Imego InstituteGöteborgSweden
  2. 2.Physikalisch-Technische BundesanstaltBerlinGermany
  3. 3.Chemical GmbHBerlinGermany

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