title: Clusters of superparamagnetic iron oxide nanoparticles encapsulated in a hydrogel: a particle architecture generating a synergistic enhancement of the T2 relaxation.
abstract: Clusters of iron oxide nanoparticles encapsulated in a pH-responsive hydrogel are synthesized and studied for their ability to alter the T(2)-relaxivity of protons. Encapsulation of the clusters with the hydrophilic coating is shown to enhance the transverse relaxation rate by up to 85% compared to clusters with no coating. With the use of pH-sensitive hydrogel, difficulties inherent in comparing particle samples are eliminated and a clear increase in relaxivity as the coating swells is demonstrated. Agreement with Monte Carlo simulations indicates that the lower diffusivity of water inside the coating and near the particle surface leads to the enhancement. This demonstration of a surface-active particle structure opens new possibilities in using similar structures for nanoparticle-based diagnostics using magnetic resonance imaging.
authors.affiliation: Steacie Institute for Molecular Sciences, National Research Council, 100 Sussex Drive, Ottawa, Ontario, Canada, K1A 0R6. chantal.paquet@nrc.ca
authors.forename: Chantal
authors.initials: C
authors.lastname: Paquet
authors.forename: Hendrick W
authors.initials: HW
authors.lastname: de Haan
authors.forename: Donald M
authors.initials: DM
authors.lastname: Leek
authors.forename: Hung-Yu
authors.initials: HY
authors.lastname: Lin
authors.forename: Bo
authors.initials: B
authors.lastname: Xiang
authors.forename: Ganghong
authors.initials: G
authors.lastname: Tian
authors.forename: Arnold
authors.initials: A
authors.lastname: Kell
authors.forename: Benoit
authors.initials: B
authors.lastname: Simard