Relaxometric Studies of gamma-Fe2O3@SiO2 Core Shell Nanoparticles: When the Coating Matters
authors Pinho, SLC; Laurent, S; Rocha, J; Roch, A; Delville, MH; Mornet, S; Carlos, LD; Vander Elst, L; Muller, RN; Geraldes, CFGC
nationality International
journal JOURNAL OF PHYSICAL CHEMISTRY C
keywords IRON-OXIDE NANOPARTICLES; SEMICONDUCTOR QUANTUM DOTS; MAGNETIC NANOPARTICLES; BIOMEDICAL APPLICATIONS; SILICA SPHERES; NANOCRYSTALS; RELAXATION; MRI; PARTICLES; AGENTS
abstract Iron oxide nanoparticles with a constant superparamagnetic core coated with a silica shell with a thickness ranging from 0.6 to 71 nm were prepared by a fast and facile soft chemistry approach. The increase of the coating thickness of the gamma-Fe2O3@SiO2 nanoparticles causes a significant decrease of the r(1) and r(2) relaxivities of their aqueous suspensions. The sizes of the nanoparticles obtained by relaxometry are significantly lower than those measured by electron microscopy. Their magnetizations measured by relaxometry also decrease relative to the values obtained by magnetometry, which correspond to the core. However, this "magnetic dilution" is smaller than expected if the entire silica shell was water impermeable. Both results indicate that a significant part of the silica coating is permeable to water. The adequate silica shell thickness may, thus, be tuned to allow for both a sufficiently high response as contrast agent and an adequate grafting of targeted biomolecules.
publisher AMER CHEMICAL SOC
issn 1932-7447
year published 2012
volume 116
issue 3
beginning page 2285
ending page 2291
digital object identifier (doi) 10.1021/jp2086413
web of science category Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary
subject category Chemistry; Science & Technology - Other Topics; Materials Science
unique article identifier WOS:000299584400032
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5 year journal impact factor (jcr 2016): 4.796
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