Cell internalization of anionic maghemite nanoparticles: Quantitative effect on magnetic resonance imaging

Anionic iron oxide nanoparticles are efficiently internalized into macrophages where they concentrate within micrometric endosomes, conferring on them a high magnetic susceptibility. The uptake of anionic maghemite nanoparticles by macrophages was quantified by an electron spin resonance (ESR) exper...

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Bibliographic Details
Published in:Magnetic resonance in medicine 2003-04, Vol.49 (4), p.646-654
Main Authors: Billotey, C., Wilhelm, C., Devaud, M., Bacri, J.C., Bittoun, J., Gazeau, F.
Format: Article
Language:English
Subjects:
Animals
Biological and medical sciences
Cell Communication
Cell Culture Techniques
cell magnetic labeling
contrast agent for MRI
Contrast Media - chemistry
Contrast Media - pharmacokinetics
Electron Spin Resonance Spectroscopy
Ferric Compounds - chemistry
Ferric Compounds - pharmacokinetics
Investigative techniques, diagnostic techniques (general aspects)
iron oxide nanoparticles
Macrophages - metabolism
Magnetic Resonance Imaging
Medical sciences
Mice
Microscopy, Electron, Scanning Transmission
Miscellaneous. Technology
Phantoms, Imaging
Radiodiagnosis. Nmr imagery. Nmr spectrometry
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Summary:Anionic iron oxide nanoparticles are efficiently internalized into macrophages where they concentrate within micrometric endosomes, conferring on them a high magnetic susceptibility. The uptake of anionic maghemite nanoparticles by macrophages was quantified by an electron spin resonance (ESR) experiment. MR spin‐echo sequences were performed with various TEs and TRs. The contrast enhancement was compared between two types of agarose phantoms with the same equivalent ferrite concentrations but containing either dispersed isolated nanoparticles or magnetically labeled macrophages. It is shown that the intracellular confinement of maghemite nanoparticles within micrometric endosomes results in a significant decrease of the longitudinal relaxivity and a moderate decrease of the transverse relaxivity compared to the relaxivities of the dispersed isolated nanoparticles. As a consequence, the signature of endosomal magnetic labeling consists of a negative contrast on T1‐weighted images in the whole ferrite concentration range, whereas the presence of extracellular isolated nanoparticles can result in a positive enhancement. Magn Reson Med 49:646–654, 2003. © 2003 Wiley‐Liss, Inc.
ISSN:0740-3194
1522-2594
DOI:10.1002/mrm.10418