scholarly journals Superparamagnetic Fe/Au Nanoparticles and Their Feasibility for Magnetic Hyperthermia

2021 ◽  
Vol 11 (14) ◽  
pp. 6637
Author(s):  
Mohamed F. Sanad ◽  
Bianca P. Meneses-Brassea ◽  
Dawn S. Blazer ◽  
Shirin Pourmiri ◽  
George C. Hadjipanayis ◽  
...  
Keyword(s):  
Room Temperature ◽  
Hysteresis Loops ◽  
Magnetic Hyperthermia ◽  
Core Shell ◽  
Face Centered Cubic ◽  
Shell Nanoparticles ◽  
Face Centered ◽  
Shell Particles ◽  
Core Shell Nanoparticles ◽  
Alternating Magnetic Fields

Today, magnetic hyperthermia constitutes a complementary way to cancer treatment. This article reports a promising aspect of magnetic hyperthermia addressing superparamagnetic and highly Fe/Au core-shell nanoparticles. Those nanoparticles were prepared using a wet chemical approach at room temperature. We found that the as-synthesized core shells assembled with spherical morphology, including face-centered-cubic Fe cores coated and Au shells. The high-resolution transmission microscope images (HRTEM) revealed the formation of Fe/Au core/shell nanoparticles. The magnetic properties of the samples showed hysteresis loops with coercivity (HC) close to zero, revealing superparamagnetic-like behavior at room temperature. The saturation magnetization (MS) has the value of 165 emu/g for the as-synthesized sample with a Fe:Au ratio of 2:1. We also studied the feasibility of those core-shell particles for magnetic hyperthermia using different frequencies and different applied alternating magnetic fields. The Fe/Au core-shell nanoparticles achieved a specific absorption rate of 50 W/g under applied alternating magnetic field with amplitude 400 Oe and 304 kHz frequency. Based on our findings, the samples can be used as a promising candidate for magnetic hyperthermia for cancer therapy.

Synthesis and Magnetic Properties of FePt /Silica Core-Shell Nanoparticles

2010 ◽  
Vol 178 ◽  
pp. 291-295 ◽  
Author(s):  
Cui Xia Li ◽  
Zhi Hong Li ◽  
Xue Yan Du ◽  
Hai Xia Guo
Keyword(s):  
Magnetic Properties ◽  
Reverse Micelles ◽  
Core Shell ◽  
Fept Nanoparticles ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Shell Nanoparticles ◽  
Transmission Electron ◽  
Face Centered ◽  
Core Shell Nanoparticles

FePt nanoparticles (NPS), ~2nm in diameter, were synthesized and then coated with silica (SiO2) shells ~1.5nm-thick using reverse micelles as nanoreactors. The silica-coated FePt core–shell (FePt @silica) NPS were characterized by direct techniques of transmission electron microscopy (TEM). The results showed that the silica shells prevented the aggregation in liquid comparing to their bare counterparts. The as-synthesized FePt@SiO2 NPS exhibited essential characteristics of superparamagnetic behavior, as investigated by a vibrating sample magnetometer (VSM). X-ray diffraction (XRD) studies proved that the annealing at 700 °C for 30min under argon atmosphere caused the crystal structure of FePt core to transform from disordered face centered cubic (fcc) to the chemically ordered L10 FePt with face-centered tetragonal (fct) structure. This phase transition caused the change of magnetic properties of the FePt@SiO2 particles from superparamagnetism to ferromagnetism.

Enhanced Magnetic Transition of Core-Shell Cobalt-Platinum Nanoalloys

2002 ◽  
Vol 721 ◽  
Author(s):  
Jong-Il Park ◽  
aNam-Jung Kang ◽  
Sang-Min Lee ◽  
Sehun Kim ◽  
S. J. Oh ◽  
...  
Keyword(s):  
Solid Solution ◽  
Room Temperature ◽  
Magnetic Transition ◽  
Information Storage ◽  
Core Shell ◽  
Magnetic Alloys ◽  
Shell Nanoparticles ◽  
General Process ◽  
Face Centered ◽  
Core Shell Nanoparticles

AbstractSynthesis of ‘solid solution’ and ‘core-shell’ types of well defined Co-Pt based nanoalloys smaller than 10nm have been achieved by redox transmetalation reactions. This redox transmetalation are selectively observed only if the redox potential between two metals is favorable. The composition of the magnetic alloys can also be tuned by adjusting the ratio of reactants. Annealed core-shell nanoparticles transformed into mixed nanoalloys with face centered tetragonal (fct) structures, which show large coercivity and ferromagnetism at room temperature. These nanoparticles can potentially be used as an independent single magnetic bit of tera-bit information storage. Also, this kind of redox transmetalation reaction can be utilized as a general process to synthesize various types of nanoalloys with controlled composition in a selective fashion.

ZnxMn1–XFe2O4@SiO2:zNd3+ Core–Shell Nanoparticles for Low-Field Magnetic Hyperthermia and Enhanced Photothermal Therapy with the Potential for Nanothermometry

2021 ◽  
Vol 4 (2) ◽  
pp. 2190-2210
Author(s):  
Marcus Vinícius-Araújo ◽  
Navadeep Shrivastava ◽  
Ailton A. Sousa-Junior ◽  
Sebastiao A. Mendanha ◽  
Ricardo Costa De Santana ◽  
...  
Keyword(s):  
Photothermal Therapy ◽  
Magnetic Hyperthermia ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Low Field ◽  
Core Shell Nanoparticles

Identification of aggregates of magnetic nanoparticles in ferrofluids at low concentrations

2003 ◽  
Vol 36 (4) ◽  
pp. 1069-1074 ◽  
Author(s):  
D. Eberbeck ◽  
A. Lange ◽  
M. Hentschel
Keyword(s):  
Magnetic Nanoparticles ◽  
Radial Distance ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Core Diameter ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Dilute Suspensions ◽  
Shell Particles ◽  
Core Shell Nanoparticles

Different very dilute suspensions of magnetic nanoparticles (magnetite surrounded by an organic shell) in water (ferrofluids) were investigated using small-angle X-ray scattering. It is shown that the scattering originates not only from noncorrelated core–shell nanoparticles, but also from larger structures. By modelling, these structures can be identified as close-packed clusters consisting of core–shell particles (core diameter ∼10 nm). The analysis of the radial distance distribution function, obtained by Fourier transformation of the scattered intensity, reveals a lower bound of the mean cluster size of about 40 nm. The formation of clusters is persistent, even in very dilute suspensions.

Monodisperse Fe3O4/Fe Core/Shell Nanoparticles with Enhanced Magnetic Property

2011 ◽  
Vol 306-307 ◽  
pp. 410-415
Author(s):  
Li Sun ◽  
Fu Tian Liu ◽  
Qi Hui Jiang ◽  
Xiu Xiu Chen ◽  
Ping Yang
Keyword(s):  
Average Diameter ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Shell Particles ◽  
Core Shell Nanoparticles

Core/shell type nanoparticles with an average diameter of 20nm were synthesized by chemical precipitation method. Firstly, Monodisperse Fe3O4 nanoparticles were synthesized by solvethermal method. FeSO4ž7H2O and NaBH4 were respectively dissolved in distilled water, then moderated Fe3O4 particles and surfactant(PVP) were ultrasonic dispersed into the FeSO4ž7H2O solution. The resulting solution was stirred 2 h at room temperature. Fe could be deposited on the surface of monodispersed Fe3O4 nanoparticles to form core-shell particles. The particles were characterized by using various experimental techniques, such as transmission electron microscopy (TEM), X-ray diffraction (XRD), AGM and DTA. The results suggest that the saturation magnetization of the nanocomposites is 100 emu/g. The composition of the samples show monodisperse and the sides of the core/shell nanoparticles are 20-30nm. It is noted that the formation of Fe3O4/Fe nanocomposites magnetite nanoparticles possess superparamagnetic property.

scholarly journals Building effective core/shell polymer nanoparticles for epoxy composite toughening based on Hansen solubility parameters

2021 ◽  
Vol 10 (1) ◽  
pp. 1183-1196
Author(s):  
Na Ning ◽  
Yiping Qiu ◽  
Yi Wei
Keyword(s):  
Interfacial Interaction ◽  
Solubility Parameters ◽  
Core Shell ◽  
Hansen Solubility Parameters ◽  
Shell Nanoparticles ◽  
Shell Particle ◽  
Uniform Dispersion ◽  
Shell Particles ◽  
Core Shell Nanoparticles ◽  
Hansen Solubility

Abstract Particles have been demonstrated to toughen epoxy resins, especially for fiber-reinforced epoxy composites, and core/shell particles are one of them. It is known that not all particles toughen the same but most evaluations are through experimentation, and few studies have been conducted to accurately predict the particles’ toughening effect or guide the design of effective particles. In this study, efforts were made to find the control factors of core/shell particles, primarily interfacial compatibility and degree of dispersion, and how to predict them. Nanocomposites were fabricated by incorporating core/shell nanoparticles having various shell polymer compositions, especially their polarities. Their compatibility was estimated using a novel quantitative approach via adopting the theory of Hansen solubility parameters (HSP), in which the HSP of core/shell nanoparticles and the epoxy matrix were experimentally determined and compared. It was found that the HSP distance was a good predictor for particle dispersion and interfacial interaction. Particles having a small HSP distance (R a) to the epoxy resin, represented by the polybutylacrylate core/polymethyl methacrylate shell particle having the smallest R a of 0.50, indicated a uniform dispersion and strong interfacial bonding with the matrix and yielded outstanding toughening performance. In contrast, polybutylacrylate core/polyacrylonitrile shell particle having the largest HSP distance (6.56) formed aggregates and exhibited low interfacial interaction, leading to poor toughness. It was also demonstrated that HSP can provide an effective strategy to facilitate the design of effective core/shell nanoparticles for epoxy toughening.

Highly active and stable Au@CuxO core–shell nanoparticles supported on alumina for carbon monoxide oxidation at low temperature

RSC Advances ◽  
2016 ◽  
Vol 6 (79) ◽  
pp. 75126-75132 ◽  
Author(s):  
Weining Zhang ◽  
Qingguo Zhao ◽  
Xiaohong Wang ◽  
Xiaoxia Yan ◽  
Sheng Han ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Low Temperature ◽  
Co Oxidation ◽  
Room Temperature ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Highly Active ◽  
Co Conversion ◽  
Core Shell Nanoparticles

Au@CuxO core–shell nanoparticles and Au@CuxO/Al2O3 used for CO oxidation at low temperature are prepared. CO conversion on Au@CuxO/Al2O3 can reach to 38% at room temperature and the catalytic activity remains unchanged after 108 hours reaction.

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