Search results for "Magnetic nanoparticle"

Size-controlled magnetic nanoparticles in surfactant-rich thin films: a combined EXAFS, SAXS, AFM and MFM study

2008

Iron oxide/oleic acid magnetic nanoparticles possessing biologically active choline derivatives

2018

Abstract In recent years, synthetic magnetic nanoparticles have made a major contribution to biomedicine. Interest in iron oxide magnetic nanoparticles conditioned by the fact that they are nontoxic, and possess the unique opportunity to deliver medicines to certain organs by external magnetic field. We have developed a synthetic procedure, which is based on binding of the first biologically active substance with the magnetic core, and subsequent immobilization of another biologically active substance (ligand) on the modified surface of nanoparticles thus creating plasma membrane-like structures. Using the proposed methodology, we have obtained new nontoxic magnetic nanoparticles, functiona…

Room Temperature Magnetism in Layered Double Hydroxides due to Magnetic Nanoparticles

2013

Some recent reports claiming room temperature spontaneous magnetization in layered double hydroxides (LDHs) have been published; however, the reported materials cause serious concern as to whether this cooperative magnetic behavior comes from extrinsic sources, such as spinel iron oxide nanoparticles. The syntheses of crystalline Fe(3+)-based LDHs with and without impurities have been developed, highlighting the care that must be taken during the synthetic process in order to avoid misidentification of magnetic LDHs.

Self-assembly and rheology of dipolar colloids in simple shear studied using multi-particle collision dynamics.

2017

Magnetic nanoparticles in a colloidal solution self-assemble in various aligned structures, which has a profound influence on the flow behavior. However, the precise role of the microstructure in the development of the rheological response has not been reliably quantified. We investigate the self-assembly of dipolar colloids in simple shear using hybrid molecular dynamics and multi-particle collision dynamics simulations with explicit coarse-grained hydrodynamics, conduct simulated rheometric studies and apply micromechanical models to produce master curves, showing evidence of the universality of the structural behavior governed by the competition between the bonding (dipolar) and erosive …

Cloud point–dispersive μ-solid phase extraction of hydrophobic organic compounds onto highly hydrophobic core–shell Fe 2 O 3 @C magnetic nanoparticles

2012

Abstract A novel two-step extraction technique combining cloud point extraction (CPE) with dispersive micro-solid phase extraction (D-μ-SPE) is presented in this work for the first time. The method involves initial extraction of the target analytes by CPE in the micelles of a non-ionic surfactant medium; then highly hydrophobic polysiloxane-coated core–shell Fe 2 O 3 @C magnetic nanoparticles (MNPs) are used to retrieve the micellar phase. In that manner, the micellar phase containing the analytes is the target of the D-μ-SPE step rather than the analytes directly. MNPs are then collected by the application of an adscititious magnetic field overcoming the need for specific steps associated …

Nanoparticles at fluid interfaces.

2017

Nanoparticles at fluid interfaces are becoming a central topic in colloid science studies. Unlike in the case of colloids in suspensions, the description of the forces determining the physical behavior of colloids at interfaces still represents an outstanding problem in the modern theory of colloidal interactions. These forces regulate the formation of complex two-dimensional structures, which can be exploited in a number of applications of technological interest; optical devices, catalysis, molecular electronics or emulsions stabilization. From a fundamental viewpoint and typical for colloidal systems, nanoparticles and microparticles at interfaces are ideal experimental and theoretical mo…

New transport properties of ferrocolloids: magnetic Soret effect and thermomagnetoosmosis

2005

The paper deals with critical analysis of experiments on thermodiffusion in ferrocolloids. The observed magnetic Soret effect is significantly stronger than that predicted theoretically. It is shown that the main reason for that is the influence of a magnetic field on mass diffusion. Besides, some measurements are effected by uncontrolled thermal and solutal magnetic convection. Even in porous media, when macroscopic convection is depressed, thermodiffusion can be disturbed by microconvective mass transfer induced by particle magnetophoresis on filter grains.

Stir bar sorptive-dispersive microextraction mediated by magnetic nanoparticles-nylon 6 composite for the extraction of hydrophilic organic compounds…

2016

A new and sensitive analytical method based on the recently developed approach termed stir bar-sorptive dispersive microextraction (SBSDME) using a magnetic CoFe2O4@SiO2-nylon 6 composite as sorbent material is presented for the extraction of hydrophilic organic compounds. The simultaneous determination of four hydrophilic UV filters in environmental water samples has been chosen as a model analytical application due to the increasing awareness regarding the occurrence of sunscreen residuals in natural waters. The developed SBSDME approach combines the principles and benefits of stir bar sorptive extraction (SBSE) and dispersive solid phase extraction (DSPE) but allows for lower extraction …

Polydopamine-coated magnetic nanoparticles for the determination of nitro musks in environmental water samples by stir bar sorptive-dispersive microe…

2021

Magnetic-based microextraction approaches have gained popularity in recent years due to the magnetic properties of the extraction phases allowing to handle them easier and more efficiently. This work describes a magnetic-based analytical method for the determination of the family of nitro musks in environmental water samples. These compounds have been of great concern due to their environmental impacts and potential health effects. The method is based on stir bar sorptive-dispersive microextraction (SBSDME) as extraction approach, prior to thermal desorption coupled to gas chromatography-mass spectrometry analysis (TD-GC-MS). For this purpose, polydopamine-coated cobalt ferrite magnetic nan…

Development of stir bar sorptive-dispersive microextraction mediated by magnetic nanoparticles and its analytical application to the determination of…

2014

A novel microextraction technique combining the principles of stir bar sorptive extraction (SBSE) and dispersive micro-solid phase extraction (DμSPE) is presented. The main feature of the method is the use of a neodymium-core stirring bar physically coated with a hydrophobic magnetic nanosorbent. Depending on stirring speed, the magnetic sorbent either acts as a coating material to the stir bar, thus affording extraction alike SBSE, or as a dispersed nanosorbent medium for the collection and extraction of the target analytes, in close analogy to DμSPE. Once the stirring process is finished, the strong magnetic field of the stir bar prevails again and rapidly retrieves the dispersed MNPs. Al…