Magnetic properties of novel superparamagnetic MRI contrast agents based on colloidal nanocrystals
Articolo
Data di Pubblicazione:
2008
Citazione:
Magnetic properties of novel superparamagnetic MRI contrast agents based on colloidal nanocrystals / M. Corti, A. Lascialfari, E. Micotti, A. Castellano, M. Donativi, A. Quarta, P.D. Cozzoli, L. Manna, T. Pellegrino, C. Sangregorio. - In: JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS. - ISSN 0304-8853. - 320:14(2008), pp. E320-E323.
Abstract:
Novel systems based on colloidal magnetic nanocrystals (NCs), potentially useful as superparamagnetic (SP) contrast agents for magnetic resonance imaging (MRI) have been investigated. The NCs we have studied comprise organic-capped single-crystalline maghemite (γ-Fe2O3) cores possessing controlled sizes and shapes. We have comparatively examined spherical and tetrapod-like NCs, the latter being branched particles possessing four arms which depart out at tetrahedral angles from a central point. The as-synthesized NCs are passivated by hydrophobic surfactant molecules and thus are fully dispersible in nonpolar media only. The NCs have been made soluble in aqueous solution by applying a procedure based on the surface intercalation and coating with an amphiphilic polymer shell. NMR relaxivities R1 and R2 were compared with ENDOREM®, one of the standard commercial SP-MRI contrast agent. We found that the spherical NCs exhibit R1 and R2 relaxivities slightly lower than those of ENDOREM®, over the whole frequency range; on the contrary, tetrapods show relaxivities about one order of magnitude lower. The physical origin of such difference in relaxivities between tetrapod- and spheres-based nanostructures is under investigation and it is possibly related to different sources of the magnetic anisotropy.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Colloidal nanocrystal; Contrast agent; Magnetic properties and NMR; Magnetic resonance imaging
Elenco autori:
M. Corti, A. Lascialfari, E. Micotti, A. Castellano, M. Donativi, A. Quarta, P.D. Cozzoli, L. Manna, T. Pellegrino, C. Sangregorio
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