scholarly journals Tailoring Interfacial Exchange Anisotropy in Hard–Soft Core-Shell Ferrite Nanoparticles for Magnetic Hyperthermia Applications

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 262
Author(s):  
Venkatesha Narayanaswamy ◽  
Imaddin A. Al-Omari ◽  
Aleksandr S. Kamzin ◽  
Bashar Issa ◽  
Ihab M. Obaidat
Keyword(s):  
Magnetic Hyperthermia ◽  
Ferrite Nanoparticles ◽  
Soft Core ◽  
Core Shell ◽  
Zero Field ◽  
Exchange Anisotropy ◽  
Shell Nanoparticles ◽  
Heating Efficiency ◽  
Two Samples ◽  
Core Shell Nanoparticles

Magnetically hard–soft core-shell ferrite nanoparticles are synthesized using an organometallic decomposition method through seed-mediated growth. Two sets of core-shell nanoparticles (S1 and S2) with different shell (Fe3O4) thicknesses and similar core (CoFe2O4) sizes are obtained by varying the initial quantities of seed nanoparticles of size 6.0 ± 1.0 nm. The nanoparticles synthesized have average sizes of 9.5 ± 1.1 (S1) and 12.2 ± 1.7 (S2) nm with corresponding shell thicknesses of 3.5 and 6.1 nm. Magnetic properties are investigated under field-cooled and zero-field-cooled conditions at several temperatures and field cooling values. Magnetic heating efficiency for magnetic hyperthermia applications is investigated by measuring the specific absorption rate (SAR) in alternating magnetic fields at several field strengths and frequencies. The exchange bias is found to have a nonmonotonic and oscillatory relationship with temperature at all fields. SAR values of both core-shell samples are found to be considerably larger than that of the single-phase bare core particles. The effective anisotropy and SAR values are found to be larger in S2 than those in S1. However, the saturation magnetization displays the opposite behavior. These results are attributed to the occurrence of spin-glass regions at the core-shell interface of different amounts in the two samples. The novel outcome is that the interfacial exchange anisotropy of core-shell nanoparticles can be tailored to produce large effective magnetic anisotropy and thus large SAR values.

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

Polymer films prepared using ionically crosslinked soft core–shell nanoparticles: a new class of nanostructured ionomers

Soft Matter ◽  
2011 ◽  
Vol 7 (1) ◽  
pp. 247-257 ◽  
Author(s):  
Orawan Pinprayoon ◽  
Robert Groves ◽  
Peter A. Lovell ◽  
Somjit Tungchaiwattana ◽  
Brian R. Saunders
Keyword(s):  
Polymer Films ◽  
Soft Core ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
New Class ◽  
Core Shell Nanoparticles

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.

Magnetic hyperthermia in brick-like Ag@Fe3O4 core–shell nanoparticles

2016 ◽  
Vol 397 ◽  
pp. 20-27 ◽  
Author(s):  
M.E.F. Brollo ◽  
J.M. Orozco-Henao ◽  
R. López-Ruiz ◽  
D. Muraca ◽  
C.S.B. Dias ◽  
...  
Keyword(s):  
Magnetic Hyperthermia ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles ◽  
Fe3o4 Core

Role of interface quality in iron oxide core/shell nanoparticles on heating efficiency and transverse relaxivity

2019 ◽  
Vol 9 (4) ◽  
pp. 328-336 ◽  
Author(s):  
Venkatesha Narayanaswamy ◽  
Ihab M. Obaidat ◽  
Sachin Latiyan ◽  
Shilpee Jain ◽  
Chiranjib Nayek ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Interface Quality ◽  
Heating Efficiency ◽  
Iron Oxide Core ◽  
Core Shell Nanoparticles

scholarly journals Adjusting the Néel relaxation time of Fe3O4/Zn x Co1−x Fe2O4 core/shell nanoparticles for optimal heat generation in magnetic hyperthermia

2020 ◽  
Vol 32 (6) ◽  
pp. 065703
Author(s):  
Fernando Fabris ◽  
Javier Lohr ◽  
Enio Lima ◽  
Adriele Aparecida de Almeida ◽  
Horacio E Troiani ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Heat Generation ◽  
Magnetic Hyperthermia ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Optimal Heat ◽  
Core Shell Nanoparticles ◽  
Néel Relaxation

scholarly journals Finding the Limits of Magnetic Hyperthermia on Core-Shell Nanoparticles Fabricated by Physical Vapor Methods

2021 ◽  
Vol 7 (4) ◽  
pp. 49
Author(s):  
Carlos Martinez-Boubeta ◽  
Konstantinos Simeonidis ◽  
Judit Oró ◽  
Antonios Makridis ◽  
David Serantes ◽  
...  
Keyword(s):  
Finite Size ◽  
Particle Morphology ◽  
Spin Coupling ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Heating Efficiency ◽  
Magnetite Fe3o4 ◽  
Metal Metal ◽  
Size And Morphology ◽  
Core Shell Nanoparticles

Magnetic nanoparticles can generate heat when exposed to an alternating magnetic field. Their heating efficacy is governed by their magnetic properties that are in turn determined by their composition, size and morphology. Thus far, iron oxides (e.g., magnetite, Fe3O4) have been the most popular materials in use, though recently bimagnetic core-shell structures are gaining ground. Herein we present a study on the effect of particle morphology on heating efficiency. More specifically, we use zero waste impact methods for the synthesis of metal/metal oxide Fe/Fe3O4 nanoparticles in both spherical and cubic shapes, which present an interesting venue for understanding how spin coupling across interfaces and also finite size effects may influence the magnetic response. We show that these particles can generate sufficient heat (hundreds of watts per gram) to drive hyperthermia applications, whereas faceted nanoparticles demonstrate superior heating capabilities than spherical nanoparticles of similar size.

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