scholarly journals Synthesis and Surface Modification of Deagglomerated Superparamagnetic Nanoparticles

1996 ◽  
Vol 432 ◽  
Author(s):  
Christoph Lesniak ◽  
Thomas Schiestel ◽  
Riüdiger Nass ◽  
Helmut Schmidt
Keyword(s):  
Surface Modification ◽  
Iron Oxide ◽  
Particle Surface ◽  
Weight Ratio ◽  
Superparamagnetic Iron Oxide ◽  
Superparamagnetic Nanoparticles ◽  
Disintegration Time ◽  
Aqueous Suspensions ◽  
Aqueous Salt Solutions ◽  
Core Particles

AbstractA method for the preparation of aminosilane coated, chemically stable, agglomerate-free superparamagnetic iron oxide nanoparticles (ferrites, e.g. Fe3O4 and γ-Fe2O3) has been developed. These nanocomposite particles posess core-shell structure. The well crystallized core particles are prepared by precipitation from aqueous salt solutions (primary particle size 10 nm). The surface modification of the weakly agglomerated core particles with aminosilane (e.g. γ-aminopropyl- triethoxysilane) leads to deagglomerated particles, covered by a thin polymerized aminosilane shell. A strong dependency of the particle/agglomerate size on the silane/iron oxideratio as well as on the disintegration time was found. A ratio of aminosilane to iron oxide of 0.8 (weight ratio) and a disintegration time of 72h result in overall particle sizes in the range of 10–15 nm. After surface modification, aminogroups are present on the particle surface (IEP of 9.5). The particles show superparamagnetic behaviour (saturation magnetization 68 EMU/g) and aqueous suspensions are stable against agglomeration. A desorption of the coating in aqueous suspensions (pH 3 to 11) is not observed.

Surface Modification of Superparamagnetic Nanoparticles for in-vivo Bio-medical Applications

2001 ◽  
Vol 704 ◽  
Author(s):  
D. K. Kim ◽  
M. Toprak ◽  
M. Mikhailova ◽  
Y. Zhang ◽  
B. Bjelke ◽  
...  
Keyword(s):  
Surface Modification ◽  
Particle Surface ◽  
Superparamagnetic Iron Oxide ◽  
Superparamagnetic Nanoparticles ◽  
Computer Assisted ◽  
Operation Conditions ◽  
Coprecipitation Process ◽  
Equilibrium Calculations ◽  
Effect Of Surface

AbstractChemical modifications of Superparamagnetic Iron Oxide Nanoparticles (SPION) surfaces by attachment of functional groups and further covalent coupling with biodegradable substances have been studied. Based on computer-assisted chemical equilibrium calculations, several optimum operation conditions for a coprecipitation process of magnetite nanoparticles were predicted. These particles were immobilized by ultra-thin films of PVA, Dextran, Dextrin, PEG and MPEG to obtain a biocompatible particle surface for further functionalization purposes. The effect of surface modification of the superparamagnetic nanoparticles in terms of chemical and physical properties of the samples was investigated with several techniques, including microelectrophoresis measurement. The feasibility of using SPION in biomedical applications was investigated by in-vivo treatment in rat brains.

scholarly journals Magnetic field-assisted assembly of iron oxide mesocrystals: a matter of nanoparticle shape and magnetic anisotropy

2019 ◽  
Vol 10 ◽  
pp. 894-900 ◽  
Author(s):  
Julian J Brunner ◽  
Marina Krumova ◽  
Helmut Cölfen ◽  
Elena V Sturm (née Rosseeva)
Keyword(s):  
Magnetic Field ◽  
Iron Oxide ◽  
Structural Difference ◽  
Superparamagnetic Iron Oxide ◽  
Directed Assembly ◽  
Homogeneous Magnetic Field ◽  
Superparamagnetic Nanoparticles ◽  
Formation Mechanisms ◽  
Nanoparticle Shape ◽  
Self Assembled

This letter describes the formation and detailed characterization of iron oxide mesocrystals produced by the directed assembly of superparamagnetic iron oxide-truncated nanocubes using the slow evaporation of the solvent within an externally applied homogeneous magnetic field. Anisotropic mesocrystals with an elongation along the direction of the magnetic field can be produced. The structure of the directed mesocrystals is compared to self-assembled mesocrystalline films, which are formed without the influence of a magnetic field. The remarkable structural difference of mesocrystals produced within the external magnetic field from those self-assembled without field indicates that the specific nanoparticle ordering within the superstructure is driven by competing of two types of anisotropic interactions caused by particle shape (i.e., faceting) and orientation of the magnetic moment (i.e., easy axes: <111>magnetite). Hence, these findings provide a fundamental understanding of formation mechanisms and structuring of mesocrystals built up from superparamagnetic nanoparticles and how a magnetic field can be used to design anisotropic mesocrystals with different structures.

scholarly journals The Local Atomic Structure of Colloidal Superparamagnetic Iron Oxide Nanoparticles for Theranostics in Oncology

Biomedicines ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 78 ◽  
Author(s):  
Elena Kuchma ◽  
Stanislav Kubrin ◽  
Alexander Soldatov
Keyword(s):  
Iron Oxide ◽  
Atomic Structure ◽  
Superparamagnetic Iron Oxide ◽  
Local Atomic Structure ◽  
Superparamagnetic Nanoparticles ◽  
Characterization Methods ◽  
X Ray ◽  
Magnetic Structures ◽  
Radiation Sources ◽  
X Ray Absorption

The paper contains an overview of modern spectroscopic methods for studying the local atomic structure of superparamagnetic nanoparticles based on iron oxide (SPIONs), which are an important class of materials promising for theranostics in oncology. Practically important properties of small and ultra small nanoparticles are determined primarily by their shape, size, and features of the local atomic, electronic, and magnetic structures, for the study of which the standard characterization methods developed for macroscopic materials are not optimal. The paper analyzes results of the studies of SPIONs local atomic structure carried out by X-ray absorption spectroscopy at synchrotron radiation sources and Mössbauer spectroscopy during the last decade.

AMF-responsive doxorubicin loaded β-cyclodextrin-decorated superparamagnetic nanoparticles

2018 ◽  
Vol 42 (1) ◽  
pp. 671-680 ◽  
Author(s):  
Evelyn C. da S. Santos ◽  
Amanda Watanabe ◽  
Maria D. Vargas ◽  
Marcelo N. Tanaka ◽  
Flavio Garcia ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Iron Oxide ◽  
Controlled Release ◽  
Iron Oxide Nanoparticles ◽  
Superparamagnetic Iron Oxide ◽  
Superparamagnetic Nanoparticles ◽  
Alternating Magnetic Field ◽  
Oxide Nanoparticles ◽  
Release System ◽  
Controlled Release System

An alternating magnetic field (AMF)-responsive controlled release system has been developed by the binding of mono-6-deoxy-6-(p-tolylsulfonyl)-β-cyclodextrin (βCD-Ts) onto amine-modified superparamagnetic iron oxide nanoparticles (MNP-NH2), resulting in a MNP-βCD nanocarrier.

scholarly journals SAXS analysis of single- and multi-core iron oxide magnetic nanoparticles

2017 ◽  
Vol 50 (2) ◽  
pp. 481-488 ◽  
Author(s):  
Wojciech Szczerba ◽  
Rocio Costo ◽  
Sabino Veintemillas-Verdaguer ◽  
Maria del Puerto Morales ◽  
Andreas F. Thünemann
Keyword(s):  
Iron Oxide ◽  
Superparamagnetic Iron Oxide ◽  
Relative Distribution ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Iron Oxide Magnetic Nanoparticles ◽  
Dense Mass ◽  
Saxs Analysis ◽  
Core Particles

This article reports on the characterization of four superparamagnetic iron oxide nanoparticles stabilized with dimercaptosuccinic acid, which are suitable candidates for reference materials for magnetic properties. Particles p1 and p2 are single-core particles, while p3 and p4 are multi-core particles. Small-angle X-ray scattering analysis reveals a lognormal type of size distribution for the iron oxide cores of the particles. Their mean radii are 6.9 nm (p1), 10.6 nm (p2), 5.5 nm (p3) and 4.1 nm (p4), with narrow relative distribution widths of 0.08, 0.13, 0.08 and 0.12. The cores are arranged as a clustered network in the form of dense mass fractals with a fractal dimension of 2.9 in the multi-core particles p3 and p4, but the cores are well separated from each other by a protecting organic shell. The radii of gyration of the mass fractals are 48 and 44 nm, and each network contains 117 and 186 primary particles, respectively. The radius distributions of the primary particle were confirmed with transmission electron microscopy. All particles contain purely maghemite, as shown by X-ray absorption fine structure spectroscopy.

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