Abstract P-8:Fe2O3-SiO2-Au Core-Shell Nanoparticles for Theranostics

Background: Core-shell nanoparticles (NPs) Fe3O4-SiO2 covered with Au grains due to their unique magnetic, biological, optical and mechanical properties are promising nanostructured material especially in biomedical field. Magnetic core allows controlling the position of NPs, SiO2 shell makes them biocompatible and decrease magnetostatic interactions between them, and Au NPs on the surface allow creating additional matrix around them and using such systems as controlled nanocontainers in tasks of drug delivery, magnetic resonance imaging and target cancer cell therapy. Methods: Inner magnetic core of the NPs was synthesized using polyol method, a 3-step process which resulting in magnetite NPs with hydrophilic surface. Shell was made by covering Fe3O4 particles in surfactant and growing SiO2 on top of them by sol-gel method. Covering core-shell NPs with 3.5 nm Au seed grains using monosilane and their further growth to control diameter. Structural properties were studied using TEM and Dual Beam SEM. Magnetic properties were investigated using LakeShore VSM 7400 magnetometer. Results: Two samples with different concentration of Au NPs were investigated. SEM observations show that core-shell Fe3O4-SiO2 are spherical with average diameter of 200 nm and Au NPs with diameter of 15 nm are evenly dispersed on their surface. Magnetic measurements showed that different concentration of Au NPs results in different coercive forces of the sample. Decreasing the temperature to 77 K showed up to 6 times increase of coercive force and slight increase in magnetization. Conclusion: Biocompatible magnetic nanoparticles are critical advances in biomedical applications. In this work, we studied the morphology of the samples, demonstrated the change of coercive force of NPs with different Au concentration and investigated their magnetic properties in low temperatures.

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Synthesis and Magnetic Properties of FePt Nanoparticles with Hard Nonmagnetic Shells

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2007.18034 ◽

2007 ◽

Vol 7 (1) ◽

pp. 350-355 ◽

Cited By ~ 3

Author(s):

Shishou Kang ◽

Shifan Shi ◽

G. X. Miao ◽

Zhiyong Jia ◽

David E. Nikles ◽

...

Keyword(s):

Magnetic Properties ◽

Crystallographic Orientation ◽

Sol Gel ◽

Molar Ratio ◽

Core Shell ◽

Fept Nanoparticles ◽

Shell Nanoparticles ◽

Spherical Core ◽

Size And Morphology ◽

Core Shell Nanoparticles

Chemically synthesized FePt nanoparticles were coated with nonmagnetic SiO2 and MnO shells by sol–gel and polyol processes. TEM images show that the FePt/SiO2 nanoparticles exhibit a thick spherical shell. The size and morphology of the MnO shell can be controlled by changing the reaction temperature, the molar ratio of surfactants/Mn(acac)2, and/or the concentration of precursor. The morphology of the MnO shell can be either spherical-like or cubic-like, depending on whether the molar ratio of surfactants/Mn(acac)2 is less than or larger than 2. From XRD measurements, the spherical core/shell nanoparticles exhibit 3D random crystallographic orientation, while the cubic core/shell nanoparticles prefer (200) texture. The magnetic moment of FePt particles can be enhanced by coating with SiO2 and MnO shells. Furthermore, the agglomeration of FePt particles upon the thermal annealing can be significantly inhibited with SiO2 and MnO shells.

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Enhanced magnetic properties and MRI performance of bi-magnetic core–shell nanoparticles

RSC Advances ◽

10.1039/c6ra14265f ◽

2016 ◽

Vol 6 (81) ◽

pp. 77558-77568 ◽

Cited By ~ 16

Author(s):

Fernando Arteaga Cardona ◽

Esmeralda Santillán Urquiza ◽

Patricia de la Presa ◽

Silvia Hidalgo Tobón ◽

Umapada Pal ◽

...

Keyword(s):

Magnetic Properties ◽

Magnetic Nanoparticles ◽

Contrast Agents ◽

Magnetic Core ◽

Mri Contrast Agents ◽

Core Shell ◽

Shell Nanoparticles ◽

Mri Contrast ◽

Core Shell Nanoparticles

Two sets of bi-magnetic, biocompatible Zn0.5Mn0.5Fe2O4@Fe3O4 core–shell nanoparticles with enhanced magnetic properties were prepared. These bi-magnetic nanoparticles have a vast potential as MRI contrast agents.

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Structural and Magnetic Properties of Well-Ordered Inverted Core-Shell α-Cr2O3/ α-MxCr2-xO3 (M=Co, Ni, Mn, Fe) Nanoparticles

MRS Advances ◽

10.1557/adv.2016.324 ◽

2016 ◽

Vol 1 (34) ◽

pp. 2387-2392 ◽

Cited By ~ 7

Author(s):

M.D. Hossain ◽

S. Dey ◽

R. A. Mayanovic ◽

M. Benamara

Keyword(s):

Magnetic Properties ◽

Oxygen Vacancy ◽

Magnetic Measurements ◽

Hysteresis Loops ◽

Core Shell ◽

Magnetic Polaron ◽

Zero Field ◽

Shell Nanoparticles ◽

Structural And Magnetic Properties ◽

Core Shell Nanoparticles

ABSTRACTMagnetic core shell nanoparticles (NPs) have potential for applications in magnetic random access memory, spintronic devices, and drug delivery systems. Our investigations are focused on the synthesis of inverted core shell nanoparticles and characterization of their structural and magnetic properties. By using our hydrothermal nanophase epitaxy technique, we are able to synthesize well-ordered α-Cr2O3@α-MxCr2-xO3 (M = Co, Ni, Mn, Fe) inverted core-shell nanoparticles. This typically results in the formation of novel phases of MxCr2-xO3 shells having ferromagnetic/ferrimagnetic (FM/FiM) spin ordering and an antiferromagnetic (AFM) Cr2O3 core structure. The combined results from XRD and high-resolution TEM (HRTEM) provide evidence of the presence of corundum phase both in the shell and in the core regions. HRTEM results also show a sharp interface exhibiting epitaxial atomic registry of shell atoms over highly ordered core atoms whereas TEM-EDX analyses show that the M atoms reside predominantly in the shell regions. The XPS analyses of the NPs indicate the M transition metals incorporated in the shell are in the +2 oxidation state. Magnetic measurements show well developed hysteresis loops: The field cooled hysteresis loops reveal horizontal shifts in the applied field axis and vertical shifts in the magnetization axis, relative to the zero-field cooled hysteresis loops. This provides direct evidence for the exchange bias effect between the AFM α-Cr2O3 core and the FM/FiM α-MxCr2-xO3 shell. The XPS data are consistent with oxygen vacancy formation in order to maintain charge neutrality upon substitution of the M2+ ion for the Cr3+ ion in the α-MxCr2-xO3 shell. The FM/FiM ordering in the shell may at least partially result from the F-center exchange coupling between the oxygen-vacancy induced bound magnetic polaron and nearby cations.

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Synthesis and Characterization of Novel Inverted NiO@NixMn1-xO Core-Shell Nanoparticles

MRS Advances ◽

10.1557/adv.2017.445 ◽

2017 ◽

Vol 2 (56) ◽

pp. 3465-3470

Author(s):

Samiul Hasan ◽

R.A. Mayanovic ◽

Mourad Benamara

Keyword(s):

Magnetic Measurements ◽

Magnetic Core ◽

Primary Objective ◽

Core Shell ◽

Zero Field ◽

Nio Nanoparticles ◽

Bias Effect ◽

Shell Nanoparticles ◽

Exchange Bias Effect ◽

Core Shell Nanoparticles

ABSTRACTMagnetic core-shell nanoparticles have the potential for numerous applications, such as in magnetic recording media, magnetic resonance imaging, drug delivery or hyperthermia, and spin valves. Inverse core-shell nanoparticles, comprised of an antiferromagnetic (AFM) core covered by a ferromagnetic (FM) or ferrimagnetic (FiM) shell, are of current interest due to the tunability of their magnetic properties. NiO is typically antiferromagnetic in nature and has a Néel temperature of 523 K. Our primary objective in this project is to synthesize and characterize inverted core-shell nanoparticles (CSNs) comprised of a NiO (AFM) core and a shell consisting of a NixMn1-xO (FM/FiM) compound. The synthesis of the CSNs was made using a two-step process. The NiO nanoparticles were synthesized using a chemical reaction method. Subsequently, the NiO nanoparticles were used to grow the NiO@NixMn1-xO CSNs using our hydrothermal nano-phase epitaxy method. XRD structural characterization shows that the NiO@NixMn1-xO CSNs have the rock salt cubic crystal structure throughout. SEM-EDS data indicates the presence of Mn in the CSNs. SQUID magnetic measurements show that the CSNs exhibit AFM/FM or AFM/FiM characteristics with a coercivity field of 425 Oe at 5 K. The field cooled vs zero field cooled hysteresis loop measurements show a significant exchange bias effect between the AFM NiO core and FM/FiM NixMn1-xO shell of the CSNs. The results of additional TEM and magnetic characterization are discussed.

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Synthesis, thermal stability, magnetic properties, and microwave absorption applications of CoNi-C core-shell nanoparticles with tunable Co/Ni molar ratio

Results in Physics ◽

10.1016/j.rinp.2021.103893 ◽

2021 ◽

Vol 22 ◽

pp. 103893

Author(s):

Lizhen Hou ◽

Xing Zhen ◽

Linlin Liu ◽

Daitao Kuang ◽

Yangyang Gao ◽

...

Keyword(s):

Thermal Stability ◽

Magnetic Properties ◽

Microwave Absorption ◽

Molar Ratio ◽

Core Shell ◽

Shell Nanoparticles ◽

Core Shell Nanoparticles

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Magnetic properties of FeCo-iron oxide core–shell nanoparticles investigated through first order reversal studies

Applied Physics A ◽

10.1007/s00339-020-04176-z ◽

2021 ◽

Vol 127 (1) ◽

Author(s):

G. Antilen Jacob ◽

R. Justin Joseyphus

Keyword(s):

Magnetic Properties ◽

Iron Oxide ◽

Core Shell ◽

Shell Nanoparticles ◽

First Order ◽

Iron Oxide Core ◽

Core Shell Nanoparticles

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Fabrication of copper(II)-coated magnetic core-shell nanoparticles Fe3O4@SiO2-2-aminobenzohydrazide and investigation of its catalytic application in the synthesis of 1,2,3-triazole compounds

Scientific Reports ◽

10.1038/s41598-021-81632-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

H. Rajabi-Moghaddam ◽

M. R. Naimi-Jamal ◽

M. Tajbakhsh

Keyword(s):

High Efficiency ◽

Click Reaction ◽

Magnetic Core ◽

Core Shell ◽

Isatoic Anhydride ◽

Shell Nanoparticles ◽

Triazole Derivatives ◽

Catalytic Application ◽

Ft Ir ◽

Core Shell Nanoparticles

AbstractIn the present work, an attempt has been made to synthesize the 1,2,3-triazole derivatives resulting from the click reaction, in a mild and green environment using the new copper(II)-coated magnetic core–shell nanoparticles Fe3O4@SiO2 modified by isatoic anhydride. The structure of the catalyst has been determined by XRD, FE-SEM, TGA, VSM, EDS, and FT-IR analyzes. The high efficiency and the ability to be recovered and reused for at least up to 6 consecutive runs are some superior properties of the catalyst.

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Magnetic-field-induced self-assembly of FeCo/CoFe2O4 core/shell nanoparticles with tunable collective magnetic properties

Nanoscale ◽

10.1039/d1nr00136a ◽

2021 ◽

Vol 13 (8) ◽

pp. 4519-4529

Author(s):

J. Mohapatra ◽

J. Elkins ◽

M. Xing ◽

D. Guragain ◽

Sanjay R. Mishra ◽

...

Keyword(s):

Magnetic Field ◽

Magnetic Properties ◽

Physical Properties ◽

Self Assembly ◽

Core Shell ◽

Shell Nanoparticles ◽

Novel Approach ◽

Core Shell Nanoparticles

Self-assembly of nanoparticles into ordered patterns is a novel approach to build up new consolidated materials with desired collective physical properties.

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Multifunktionale bakterielle Nanomagnete für Biotechnologie und Medizin

BIOspektrum ◽

10.1007/s12268-021-1593-5 ◽

2021 ◽

Vol 27 (4) ◽

pp. 442-444

Author(s):

Frank Mickoleit ◽

Sabine Rosenfeldt ◽

Anna S. Schenk ◽

Dirk Schüler ◽

René Uebe

Keyword(s):

Particle Production ◽

Magnetotactic Bacteria ◽

Magnetic Core ◽

High Yield ◽

Core Shell ◽

Shell Nanoparticles ◽

Magnetospirillum Gryphiswaldense ◽

Core Shell Nanoparticles ◽

Genetic Toolkit ◽

The Way

AbstractBacterial magnetosomes represent magnetic core-shell nanoparticles biomineralized by magnetotactic bacteria like Magnetospirillum gryphiswaldense. The establishment of fermentation regimes for high-yield particle production, standardized isolation procedures as well as the development of a genetic toolkit for the generation of “tailored” particles might soon pave the way for the application of engineered magnetosomes in the biomedical and biotechnological field.

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