A quantitative study of particle size effects in the magnetorelaxometry of magnetic nanoparticles using atomic magnetometry
- Dolgovskiy, Vladimir Physics Department, University of Fribourg, Switzerland
- Lebedev, Victor Physics Department, University of Fribourg, Switzerland
- Colombo, Simone Physics Department, University of Fribourg, Switzerland
- Weis, Antoine Physics Department, University of Fribourg, Switzerland
- Michen, Benjamin Adolphe Merkle Institute, University of Fribourg, Switzerland
- Ackermann-Hirschi, Liliane Adolphe Merkle Institute, University of Fribourg, Switzerland
- Petri-Fink, Alke Adolphe Merkle Institute, University of Fribourg, Switzerland - Chemistry Department, University of Fribourg, Switzerland
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01.04.2015
Published in:
- Journal of Magnetism and Magnetic Materials. - 2015, vol. 379, p. 137–150
Magnetorelaxometry
Superparamagnetic nanoparticles
Atomic magnetometry
Néel and Brownian relaxation
Maghemite
English
The discrimination of immobilised superparamagnetic iron oxide nanoparticles (SPIONs) against SPIONs in fluid environments via their magnetic relaxation behaviour is a powerful tool for bio-medical imaging. Here we demonstrate that a gradiometer of laser-pumped atomic magnetometers can be used to record accurate time series of the relaxing magnetic field produced by pre-polarised SPIONs. We have investigated dry in vitro maghemite nanoparticle samples with different size distributions (average radii ranging from 14 to 21 nm) and analysed their relaxation using the Néel–Brown formalism. Fitting our model function to the magnetorelaxation (MRX) data allows us to extract the anisotropy constant K and the saturation magnetisation MS of each sample. While the latter was found not to depend on the particle size, we observe that K is inversely proportional to the (time- and size-) averaged volume of the magnetised particle fraction. We have identified the range of SPION sizes that are best suited for MRX detection considering our specific experimental conditions and sample preparation technique.
- Faculty
- Faculté des sciences et de médecine
- Department
- Département de Physique, AMI - Bio-Nanomatériaux
- Language
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- English
- Classification
- Physics
- License
- License undefined
- Identifiers
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- RERO DOC 235701
- DOI 10.1016/j.jmmm.2014.12.007
- Persistent URL
- https://folia.unifr.ch/unifr/documents/304300
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