Clusters of magnetic nanoparticles as contrast agents for MRI: effect of aggregation on transverse relaxivity

0450596 - FZÚ 2017 RIV US eng J - Journal Article
Dědourková, T. - Kaman, Ondřej - Veverka, Pavel - Koktan, Jakub - Veverka, Miroslav - Kuličková, Jarmila - Jirák, Zdeněk - Herynek, V.
Clusters of magnetic nanoparticles as contrast agents for MRI: effect of aggregation on transverse relaxivity.
IEEE Transactions on Magnetics. Roč. 51, č. 11 (2015), s. 5300804. ISSN 0018-9464. E-ISSN 1941-0069
R&D Projects: GA ČR GA15-10088S; GA MPO FR-TI3/521
Institutional support: RVO:68378271
Keywords : contrast agents * magnetic resonance imaging * magnetic nanoparticles * manganites * transverse relaxivity
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 1.277, year: 2015

The effect of aggregation of magnetic nanoparticles on the transverse relaxivity (r2) is analyzed with respect to the size of clusters. The nanoparticles employed are based on La0.75Sr0.25MnO3 phase with the mean size of crystallites dXRD = 26 nm. Silica coating provides colloidally stable particles whose magnetic cores are mostly composed of clusters of manganite crystallites. The product is subjected to differential centrifugation and several size fractions, possessing the same dXRD but differing in the effective size of magnetic cores, are isolated. Thorough analyses of their size distributions by TEM and DLS are carried out together with SQUID magnetometry. The concentration of particles is accurately determined by AAS and a detailed study of r2 at the magnetic field B0 = 0.5 T is performed. The highest r2 values are clearly observed for mid-sized clusters and the temperature dependence of r2 resembles the evolution of magnetization with temperature.
Permanent Link: http://hdl.handle.net/11104/0251868