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. H-1-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 (R), over an extended frequency range (1-60 MHz). The marked increase in the transverse relaxivity r(2) at a clinical magnetic field strength (similar to 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 T-2-weighted magnetic resonance images.

Colloidal assemblies of oriented maghemite nanocrystals and their NMR relaxometric properties / A. Kostopoulou, S. Kunjipalayam Palaniswamy Velu, K. Thangavel, F. Orsini, K. Brintakis, S. Psycharakis, A. Ranella, L. Bordonali, A. Lappas, A. Lascialfari. - In: DALTON TRANSACTIONS. - ISSN 1477-9226. - 43:22(2014), pp. 8395-8404. [10.1039/c4dt00024b]

Colloidal assemblies of oriented maghemite nanocrystals and their NMR relaxometric properties

S. Kunjipalayam Palaniswamy Velu;K. Thangavel;F. Orsini;A. Lascialfari
2014

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. H-1-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 (R), over an extended frequency range (1-60 MHz). The marked increase in the transverse relaxivity r(2) at a clinical magnetic field strength (similar to 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 T-2-weighted magnetic resonance images.
Settore FIS/03 - Fisica della Materia
Settore FIS/01 - Fisica Sperimentale
Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin)
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/247307
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