Core–shell La 1− x Sr x MnO 3 nanoparticles as colloidal mediators for magnetic fluid hyperthermia

2010 ◽  
Vol 368 (1927) ◽  
pp. 4389-4405 ◽  
Author(s):  
E. Pollert ◽  
O. Kaman ◽  
P. Veverka ◽  
M. Veverka ◽  
M. Maryško ◽  
...  
Keyword(s):  
Sol Gel ◽  
Size Fraction ◽  
Core Shell ◽  
Magnetic Studies ◽  
Shell Nanoparticles ◽  
Water Suspension ◽  
Heating Efficiency ◽  
Morphological Studies ◽  
Biological Studies ◽  
Core Shell Nanoparticles

Core–shell nanoparticles consisting of La 0.75 Sr 0.25 MnO 3 cores covered by silica were synthesized by a procedure consisting of several steps, including the sol–gel method in the presence of citric acid and ethylene glycol, thermal and mechanical treatment, encapsulation employing tetraethoxysilane and final separation by centrifugation in order to get the required size fraction. Morphological studies revealed well-separated particles that form a stable water suspension. Magnetic studies include magnetization measurements and investigation of the ferromagnetic–superparamagnetic–paramagnetic transition. Magnetic heating experiments in ‘calorimetric mode’ were used to determine the heating efficiency of the particles in water suspension and further employed for biological studies of extracellular and intracellular effects analysed by tests of viability.

scholarly journals Enhancement of Luminescence Efficiency of Y2O3 Nanophosphor via Core/Shell Structure

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1563
Author(s):  
Jae-Young Hyun ◽  
Ki-Hyun Kim ◽  
Jae-Pil Kim ◽  
Won-Bin Im ◽  
Kadathala Linganna ◽  
...  
Keyword(s):  
Annealing Temperature ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Core Shell ◽  
Molten Salt Method ◽  
Shell Nanoparticles ◽  
Morphological Studies ◽  
Luminescence Efficiency ◽  
Higher Temperature ◽  
Core Shell Nanoparticles

We successfully fabricated Y2O3:RE3+ (RE = Eu, Tb, and Dy) core and core–shell nanophosphors by the molten salt method and sol–gel processes with Y2O3 core size of the order of 100~150 nm. The structural and morphological studies of the RE3+-doped Y2O3 nanophosphors are analyzed by using XRD, SEM and TEM techniques, respectively. The concentration and annealing temperature dependent structural and luminescence characteristics were studied for Y2O3:RE3+ core and core–shell nanophosphors. It is observed that the XRD peaks became narrower as annealing temperature increased in the core–shell nanophosphor. This indicates that annealing at higher temperature improves the crystallinity which in turn enhances the average crystallite size. The emission intensity and quantum yield of the Eu3+-doped Y2O3 core and core–shell nanoparticles increased significantly when annealing temperature is varied from 450 to 550 °C. No considerable variation was noticed in the case of Y2O3:Tb3+ and Y2O3:Dy3+ core and core–shell nanophosphors.

Synthesis and magnetic studies of Ni/NiO core/shell nanoparticles

2015 ◽  
Author(s):  
C. Rinsha ◽  
C. N. Anumol ◽  
M. Chithra ◽  
B. N. Sahu ◽  
Subasa C. Sahoo
Keyword(s):  
Core Shell ◽  
Magnetic Studies ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles

scholarly journals PREPARATION OF CORE-SHELL SILVER/SILICA NANOPATICLES AND THEIR APPLICATION FOR ENHANCEMENT OF CYANINE 3 FLUORESCENCE

2012 ◽  
Vol 11 (04) ◽  
pp. 1240020 ◽  
Author(s):  
N. SUI ◽  
V. MONNIER ◽  
Z. YANG ◽  
Y. CHEVOLOT ◽  
E. LAURENCEAU ◽  
...  
Keyword(s):  
Steady State ◽  
Fluorescence Spectroscopy ◽  
Sol Gel ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Steady State Fluorescence ◽  
Covalently Bonded ◽  
Core Shell Nanoparticles ◽  
Steady State Fluorescence Spectroscopy ◽  
Silver Core

Core shell Ag@SiO2 -Streptavidin- Cy3 nanoparticles were prepared. Ag@SiO2 nanoparticles were synthesized via a sol–gel method. Then, Streptavidin- Cy3 was covalently bonded to the Ag@SiO2 surface. These core-shell nanoparticles were characterized by steady-state fluorescence spectroscopy and fluorescence scanning. In presence of the silver core, a 2.5-time enhancement of Cy3 fluorescence intensity was obtained. This result shows that these nanoparticles can be potentially helpful in surface analysis based on biochip.

Synthesis and Magnetic Properties of FePt Nanoparticles with Hard Nonmagnetic Shells

2007 ◽  
Vol 7 (1) ◽  
pp. 350-355 ◽  
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.

Preparation and characterization of sol–gel derived Er3+–Yb3+ codoped SiO2/TiO2 core–shell nanoparticles

2010 ◽  
Vol 64 (7) ◽  
pp. 846-848 ◽  
Author(s):  
Shujie Pang ◽  
Xianliang Li ◽  
Zuosen Shi ◽  
Guang Yang ◽  
Zhanchen Cui
Keyword(s):  
Sol Gel ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles

scholarly journals Fabrication of Magnetite/Silica/Titania Core-Shell Nanoparticles

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Suh Cem Pang ◽  
Sze Yun Kho ◽  
Suk Fun Chin
Keyword(s):  
Methylene Blue ◽  
Uv Light ◽  
Sol Gel ◽  
Core Shell ◽  
Silica Nanospheres ◽  
Shell Nanoparticles ◽  
Gel Method ◽  
Uv Light Irradiation ◽  
Silica Nanosphere ◽  
Core Shell Nanoparticles

Fe3O4/SiO2/TiO2core-shell nanoparticles were synthesized via a sol-gel method with the aid of sonication. Fe3O4nanoparticles were being encapsulated within discrete silica nanospheres, and a layer of TiO2shell was then coated directly onto each silica nanosphere. As-synthesized Fe3O4/SiO2/TiO2core-shell nanoparticles showed enhanced photocatalytic properties as evidenced by the enhanced photodegradation of methylene blue under UV light irradiation.

scholarly journals Conjugation of oligo-His peptides to magnetic γ-Fe2O3@SiO2 core-shell nanoparticles promotes their access to the cytosol

2021 ◽  
Author(s):  
Mathilde Le Jeune ◽  
Emilie Secret ◽  
Michaël Trichet ◽  
Aude Michel ◽  
Delphine Ravault ◽  
...  
Keyword(s):  
Cell Penetrating Peptides ◽  
Endosomal Escape ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Heating Efficiency ◽  
Multiple Substrates ◽  
Transmission Electron ◽  
Cell Penetrating ◽  
Calcein Leakage ◽  
Core Shell Nanoparticles

The endosomal entrapment of functional nanoparticles is a severe limitation to their use for biomedical applications. In the case of magnetic nanoparticles (MNPs), this entrapment leads to poor heating efficiency for magnetic hyperthermia and suppresses the possibility to manipulate them in the cytosol. Current strategies to limit their entrapment are based on their functionalization with cell-penetrating peptides in order to promote their translocation directly across the cell membrane or their endosomal escape. However, these strategies suffer from potential release of free peptides in cell and to the best of our knowledge there is currently a lack of effective methods for the cytosolic delivery of MNPs after incubation with cells. Herein, we report the conjugation of fluorescently labelled cationic peptides to γ-Fe2O3@SiO2 core-shell nanoparticles by click chemistry to improve MNP access to the cytosol. We compare the effect of Arg9 and His4 peptides. On one hand, Arg9 is a classical cell-penetrating peptide, able to enter cells by direct translocation and on the other hand, it has been demonstrated that sequences rich in histidine residues promote endosomal escape, most probably by the proton sponge effect. The methodology developed allows to have a high co-localization of the peptides and core-shell nanoparticles in cells and to attest that the grafting onto nanoparticles of peptides rich in histidine promotes NP access to the cytosol. The endosomal escape was confirmed by a calcein leakage assay and by ultrastructural analysis in transmission electron microscopy. No toxicity of the nanoparticles functionalized with peptides was found. We show that our conjugation strategy is compatible with the addition of multiple substrates and can thus be used for the delivery of cytoplasm-targeted therapeutics.

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