Colloidal Ordered Assemblies in a Polymer Shell—A Novel Type of Magnetic Nanobeads for Theranostic Applications

Abstract

We present the synthesis of polymer embedded colloidal ordered assemblies, built from highly ordered superparamagnetic manganese iron oxide nanocrystals. Each assembly is wrapped into a thin polymer shell. In-depth characterization of the nanoparticles by TEM, SAXS, SQUID, and magnetophoresis indicates that these colloidal hybrids exhibit high mobilities in external magnetic fields, and that they could efficiently serve as contrast enhancers in magnetic resonance imaging.

Nanoparticle Clusters: Assembly and Control Over Internal Order, Current Capabilities, and Future Potential

“…In an interesting extension of the NPC formation mechanism, the same group [90] recently introduced a two-step collapse of the colloid. Initially the NPs were destabilized by gradual addition of acetonitrile to oleate-stabilized NPs in THF, to form colloidal close-packed (face-centered cubic (fcc)) ordered assemblies of the NPs.…”

Magnetic iron oxide nanoparticles: Recent trends in design and synthesis of magnetoresponsive nanosystems

“…Therefore, in order to assess the magnetic targeting / fixing applicability of magnetic particles, the particles' magnetic moment is more relevant than mass magnetization [45,50]. The magnetic targeting potential of multicore particles, in particular the magnetic moment and magnetic mobility were determined in recent magnetophoresis investigations [45,[50][51][52][53][54] ( Table 1).…”

“…The localization and amount of magnetic nanoparticles in the magnetic-nonmagnetic material structure, such as assembling onto the surface of a non-magnetic core [87], homogeneous distribution in a non-magnetic matrix, entrapment into a vesicle bilayer [19] or close packing into a magnetic core, which are essential for the overall magnetic response, favor the magnetic core-organic shell type nanostructures [88]. Magnetic nanoparticle clusters in a polymer shell, summing up the magnetic moments of individual nanoparticles, were obtained by in situ coprecipitation of magnetic nanoparticles in microgels as microreactors [79,80] and also by strongly polar solvent induced destabilization of a ferrofluid [53]. The controlled clusterization of magnetic nanoparticles using the well-established miniemulsion technique [91], followed M A N U S C R I P T…”

“…The dark pattern (A) results from the ordering of the closed packed assemblies within the nanobeads, while the brighter gray ring is caused by the polymer shell (lower electron density) of around 20 nm thickness. (Reprinted with permission from[53]. Copyright (2013) American Chemical Society); right -HRTEM of multi-core NP showing the continuity of the crystal lattice at the grain interfaces.…”

Magnetic microgels for drug targeting applications: Physical–chemical properties and cytotoxicity evaluation

“…The high magnetic moment of the functionalized carriers is among the most important requirements for successful applications in biomedicine, in particular for magnetic targeting [9]. Magnetic nanoparticle clusters in a polymer shell, summing up the magnetic moments of individual nanoparticles, were obtained by in situ coprecipitation of magnetic nanoparticles in microgels as microreactors [10,11] and also by strongly polar solvent induced destabilization of a ferrofluid [12]. The controlled clusterization of magnetic nanoparticles, followed by encapsulation of the densely packed magnetic core in a polymer shell proved to be a facile and reproducible procedure when using the well-established ferrofluid technology and oil-in-water miniemulsion procedure [13,14,15].…”