Nanometer-Scale Iron Oxide Magnetic Particles: Synthesis and Magnetic Properties

1990 ◽  
Vol 206 ◽  
Author(s):  
John K. Vassiliou ◽  
Vivek Mehrotra ◽  
Michael W. Russell ◽  
Emmanuel P. Giannelis
Keyword(s):  
Magnetic Susceptibility ◽  
Iron Oxide ◽  
Magnetic Particles ◽  
Average Diameter ◽  
Nanometer Scale ◽  
Iron Oxide Particles ◽  
Porous Network ◽  
Synthesis Conditions ◽  
Oxide Particles ◽  
The Magnetic Field

ABSTRACTNanometer-scale iron oxide magnetic particles have been formed in the porous network of a cross-linked polymer matrix by ion exchange and subsequent hydrolysis. The oxide particles are uniform, well-dispersed and spherical with a diameter ranging between 30 and 1200 Å depending on the synthesis conditions. The DC magnetic susceptibility, measured between 4 and 300 K, continuously increases with decreasing temperature and tends to saturate at low temperatures. Composites containing iron oxide particles with an average diameter of 80 Å exhibit superparamagnetism while those on the order of 1000 Å undergo an antiferromagnetic-type transition at 33 K. The magnetic susceptibility is critically dependent upon the particle size and the strength of the magnetic field.

scholarly journals Magnetic Particles: Their Applications from Sample Preparations to Biosensing Platforms

Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 302 ◽  
Author(s):  
Seong-Eun Kim ◽  
My Van Tieu ◽  
Sei Young Hwang ◽  
Min-Ho Lee
Keyword(s):  
Iron Oxide ◽  
Magnetic Materials ◽  
Magnetic Particles ◽  
Ease Of Use ◽  
Iron Oxide Particles ◽  
Scientific Publications ◽  
Magnetic Iron Oxide ◽  
Automation Systems ◽  
Target Molecules ◽  
Oxide Particles

The growing interest in magnetic materials as a universal tool has been shown by an increasing number of scientific publications regarding magnetic materials and its various applications. Substantial progress has been recently made on the synthesis of magnetic iron oxide particles in terms of size, chemical composition, and surface chemistry. In addition, surface layers of polymers, silica, biomolecules, etc., on magnetic particles, can be modified to obtain affinity to target molecules. The developed magnetic iron oxide particles have been significantly utilized for diagnostic applications, such as sample preparations and biosensing platforms, leading to the selectivity and sensitivity against target molecules and the ease of use in the sensing systems. For the process of sample preparations, the magnetic particles do assist in target isolation from biological environments, having non-specific molecules and undesired molecules. Moreover, the magnetic particles can be easily applied for various methods of biosensing devices, such as optical, electrochemical, and magnetic phenomena-based methods, and also any methods combined with microfluidic systems. Here we review the utilization of magnetic materials in the isolation/preconcentration of various molecules and cells, and their use in various techniques for diagnostic biosensors that may greatly contribute to future innovation in point-of-care and high-throughput automation systems.

Encapsulation of ferromagnetic iron oxide particles by polyester resin

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
H. Baharvand
Keyword(s):  
Iron Oxide ◽  
Magnetic Particles ◽  
Polyester Resin ◽  
Thermo Gravimetric Analysis ◽  
Oxide Content ◽  
Gravimetric Analysis ◽  
Distribution Analysis ◽  
Polymer Phase ◽  
Iron Oxide Particles ◽  
Oxide Particles

AbstractMagnetic iron oxide (maghemite, Fe3O4) particles were encapsulated with polyester resin. The resulting magnetic powders were characterized by Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), Fritsch particle sizer, scanning electron microscopy (SEM), X-ray diffractometer (XRD) and vibrating sample magnetometer (VSM) measurements. FTIR and XRD confirmed the presence of iron oxide in polymer phase. The TGA and DSC measurements indicated the magnetic polymer particles have more than 50% iron oxide content and high thermal stability. SEM revealed that all maghemite particles were embedded in the polymer phase. The size distribution analysis of prepared magnetic particles has shown that the mean diameter of the bare iron oxide particles slightly increased with encapsulation. According to our magnetometry data, shape of the loops evidences the ferromagnetic character of the material and no evidence of superparamagnetism was seen.

scholarly journals Magnetic microparticle concentration and collection using a mechatronic magnetic ratcheting system

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246124
Author(s):  
Oladunni B. Adeyiga ◽  
Coleman Murray ◽  
Hector E. Muñoz ◽  
Alberto Escobar ◽  
Dino Di Carlo
Keyword(s):  
Magnetic Field ◽  
Iron Oxide ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Concentration Factor ◽  
Magnetic Particles ◽  
Superparamagnetic Iron Oxide ◽  
Iron Oxide Particles ◽  
Superparamagnetic Iron Oxide Particles ◽  
Oxide Particles

Magnetic ratcheting cytometry is a promising approach to separate magnetically-labeled cells and magnetic particles based on the quantity of magnetic material. We have previously reported on the ability of this technique to separate magnetically-labeled cells. Here, with a new chip design, containing high aspect ratio permalloy micropillar arrays, we demonstrate the ability of this technique to rapidly concentrate and collect superparamagnetic iron oxide particles. The platform consists of a mechatronic wheel used to generate and control a cycling external magnetic field that impinges on a “ratcheting chip.” The ratcheting chip is created by electroplating a 2D array of high aspect ratio permalloy micropillars onto a glass slide, which is embedded in a thin polymer layer to create a planar surface above the micropillars. By varying magnetic field frequency and direction through wheel rotation rate and angle, we direct particle movement on chip. We explore the operating conditions for this system, identifying the effects of varying ratcheting frequency, along with time, on the dynamics and resulting concentration of these magnetic particles. We also demonstrate the ability of the system to rapidly direct the movement of superparamagnetic iron oxide particles of varying sizes. Using this technique, 2.8 μm, 500 nm, and 100 nm diameter superparamagnetic iron oxide particles, suspended within an aqueous fluid, were concentrated. We further define the ability of the system to concentrate 2.8 μm superparamagnetic iron oxide particles, present in a liquid suspension, into a small chip surface area footprint, achieving a 100-fold surface area concentration, and achieving a concentration factor greater than 200%. The achieved concentration factor of greater than 200% could be greatly increased by reducing the amount of liquid extracted at the chip outlet, which would increase the ability of achieving highly sensitive downstream analytical techniques. Magnetic ratcheting-based enrichment may be useful in isolating and concentrating subsets of magnetically-labeled cells for diagnostic automation.

The Magnetic Field of Magnetic Resonance Imaging Systems Does Not Affect Cells Labeled with Micrometer-Sized Iron Oxide Particles

2017 ◽  
Vol 23 (7) ◽  
pp. 412-421 ◽  
Author(s):  
Martin Kluge ◽  
Annekatrin Leder ◽  
Karl H. Hillebrandt ◽  
Benjamin Struecker ◽  
Dominik Geisel ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Field ◽  
Iron Oxide ◽  
Magnetic Resonance ◽  
Imaging Systems ◽  
Resonance Imaging ◽  
Iron Oxide Particles ◽  
Oxide Particles ◽  
The Magnetic Field

Magnetic Particles Retaining on Open and Closed Systems

2019 ◽  
Vol 826 ◽  
pp. 25-29
Author(s):  
George Banis ◽  
Emmanouela Mangiorou ◽  
Panagiota Tselou ◽  
Angelo Ferraro ◽  
Evangelos Hristoforou
Keyword(s):  
Iron Oxide ◽  
Magnetic Particles ◽  
Cost Effective ◽  
Biofuel Production ◽  
Main Stream ◽  
Iron Oxide Particles ◽  
Magnetic Elements ◽  
Closed Type ◽  
Oxide Particles ◽  
Good Productivity

In recent decades the application of magnetic iron oxide micro-and nanoparticles has been established in various technological fields, such as magnetic separation of biomolecules and ions, biosensors, biofuel production and others [1-4]. Working with iron oxide particles is becoming main stream subject thanks to the facility that this kind of materials can be functionalized with a variety of chemical groups which confer them specific selective or catalytic properties [5]. Furthermore, iron oxide nanoparticles present magnetic properties, and in particular super-paramagnetism, which allows to remotely control them making their manipulation easy and cost-effective [6]. In addition, a new method of synthesis has been recently proposed, which can guarantee a cost-effective production of magnetic particles that may further reduce the running cost of separation methods based on magnetism [7]. Nevertheless, biotechnological applications of iron oxide particles are still confined to research level (lab scale devices) or for low throughput clinical applications [8,9]. Indeed, most systems based on the use of magnetic elements are design to work with microfluid dynamic or are able to process samples in bath-based fashion, therefore discontinuously. The need of robust and high-productive methods is demanded especially in bioscience where, independently from the reaction or process involving magnetic particles, once such composite materials are mixed or added to a given solution, inevitably at the end of workflow they must be separated/harvested from the reaction vessel. Therefore, it is vital for a good productivity and processivity of reactions involving magnetic particles to ensure that large volumes of solution can be treated, and magnetic particles withdrew in the most fast and accurate way. The purpose of this paper is to compare an open and a closed type magnetic trapping system regarding their efficiency using two different types of magnetic sources.

scholarly journals Multimodal imaging of micron-sized iron oxide particles followingin vitroandin vivouptake by stem cells: down to the nanometer scale

2014 ◽  
Vol 9 (6) ◽  
pp. 400-408 ◽  
Author(s):  
Dimitri Roose ◽  
Frederic Leroux ◽  
Nathalie De Vocht ◽  
Caroline Guglielmetti ◽  
Isabel Pintelon ◽  
...  
Keyword(s):  
Stem Cells ◽  
Iron Oxide ◽  
Multimodal Imaging ◽  
Nanometer Scale ◽  
Iron Oxide Particles ◽  
Oxide Particles

scholarly journals Preparation and characterization of hydroxyapatite-coated iron oxide particles by spray-drying technique

2009 ◽  
Vol 81 (2) ◽  
pp. 179-186 ◽  
Author(s):  
karina Donadel ◽  
Marcos D.V. Felisberto ◽  
Mauro C.M. Laranjeira
Keyword(s):  
Iron Oxide ◽  
Spray Drying ◽  
Magnetic Particles ◽  
Absorption Spectrometry ◽  
Spherical Particles ◽  
Iron Oxide Particles ◽  
X Ray ◽  
Flame Atomic Absorption ◽  
Oxide Particles

Magnetic particles of iron oxide have been increasingly used in medical diagnosis by magnetic resonance imaging and in cancer therapies involving targeted drug delivery and magnetic hyperthermia. In this study we report the preparation and characterization of iron oxide particles coated with bioceramic hydroxyapatite by spray-drying. The iron oxide magnetic particles (IOMP) were coated with hydroxyapatite (HAp) by spray-drying using two IOMP/HAp ratios (0.7 and 3.2). The magnetic particles were characterized by way of scanning electronic microscopy, energy dispersive X-ray, X-ray diffraction, Fourier transformed infrared spectroscopy, flame atomic absorption spectrometry,vibrating sample magnetometry and particle size distribution (laser diffraction). The surface morphology of the coated samples is different from that of the iron oxide due to formation of hydroxyapatite coating. From an EDX analysis, it was verified that the surface of the coated magnetic particles is composed only of HAp, while the interior containsiron oxide and a few layers of HAp as expected. The results showed that spray-drying technique is an efficient and relatively inexpensive method for forming spherical particles with a core/shell structure.

scholarly journals Aqueous one-pot synthesis of well-defined zwitterionic diblock copolymers by RAFT polymerization: an efficient and environmentally-friendly route to a useful dispersant for aqueous pigments

2021 ◽  
Vol 23 (3) ◽  
pp. 1248-1258
Author(s):  
Shannon M. North ◽  
Steven P. Armes
Keyword(s):  
Iron Oxide ◽  
Diblock Copolymers ◽  
Raft Polymerization ◽  
Environmentally Friendly ◽  
Iron Oxide Particles ◽  
One Pot ◽  
One Pot Synthesis ◽  
Highly Effective ◽  
Oxide Particles

An atom-efficient, wholly aqueous one-pot synthesis of zwitterionic diblock copolymers has been devised. Such copolymers can serve as highly effective aqueous dispersants for nano-sized transparent yellow iron oxide particles.

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