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Issue 22, 2014
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Colloidal assemblies of oriented maghemite nanocrystals and their NMR relaxometric properties

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Abstract

An elevated-temperature polyol-based colloidal-chemistry approach allows for the development of size-tunable (50 and 86 nm) assemblies of maghemite iso-oriented nanocrystals, with enhanced magnetization. 1H-nuclear magnetic resonance (NMR) relaxometric experiments show that the ferrimagnetic cluster-like colloidal entities exhibit a remarkable enhancement (4–5 times) in transverse relaxivity when compared to that of the superparamagnetic contrast agent Endorem®, over an extended frequency range (1–60 MHz). The marked increase in the transverse relaxivity r2 at a clinical magnetic field strength (∼1.41 T), which is 405.1 and 508.3 mM−1 s−1 for small and large assemblies, respectively, makes it possible to relate the observed response to the raised intra-aggregate magnetic material volume fraction. Furthermore, cell tests with a murine fibroblast culture medium confirmed cell viability in the presence of the clusters. We discuss the NMR dispersion profiles on the basis of relaxivity models to highlight the magneto-structural characteristics of the materials for improved T2-weighted magnetic resonance images.

Graphical abstract: Colloidal assemblies of oriented maghemite nanocrystals and their NMR relaxometric properties

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Publication details

The article was received on 04 Jan 2014, accepted on 24 Feb 2014 and first published on 16 Apr 2014


Article type: Paper
DOI: 10.1039/C4DT00024B
Author version available: Download Author version (PDF)
Citation: Dalton Trans., 2014,43, 8395-8404
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    Colloidal assemblies of oriented maghemite nanocrystals and their NMR relaxometric properties

    A. Kostopoulou, S. K. P. Velu, K. Thangavel, F. Orsini, K. Brintakis, S. Psycharakis, A. Ranella, L. Bordonali, A. Lappas and A. Lascialfari, Dalton Trans., 2014, 43, 8395
    DOI: 10.1039/C4DT00024B

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