scholarly journals Increase of magnetic hyperthermia efficiency due to dipolar interactions in low-anisotropy magnetic nanoparticles: Theoretical and experimental results

2013 ◽  
Vol 87 (17) ◽  
Author(s):  
B. Mehdaoui ◽  
R. P. Tan ◽  
A. Meffre ◽  
J. Carrey ◽  
S. Lachaize ◽  
...  
2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yaser Hadadian ◽  
Ana Paula Ramos ◽  
Theo Z. Pavan

AbstractOptimizing the intrinsic properties of magnetic nanoparticles for magnetic hyperthermia is of considerable concern. In addition, the heating efficiency of the nanoparticles can be substantially influenced by dipolar interactions. Since adequate control of the intrinsic properties of magnetic nanoparticles is not straightforward, experimentally studying the complex interplay between these properties and dipolar interactions affecting the specific loss power can be challenging. Substituting zinc in magnetite structure is considered as an elegant approach to tune its properties. Here, we present experimental and numerical simulation results of magnetic hyperthermia studies using a series of zinc-substituted magnetite nanoparticles (ZnxFe1-xFe2O4, x = 0.0, 0.1, 0.2, 0.3 and 0.4). All experiments were conducted in linear regime and the results were inferred based on the numerical simulations conducted in the framework of the linear response theory. The results showed that depending on the nanoparticles intrinsic properties, interparticle interactions can have different effects on the specific loss power. When dipolar interactions were strong enough to affect the heating efficiency, the parameter σ = KeffV/kBT (Keff is the effective anisotropy and V the volume of the particles) determined the type of the effect. Finally, the sample x = 0.1 showed a superior performance with a relatively high intrinsic loss power 5.4 nHm2kg−1.


Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3240
Author(s):  
Michael Zeinoun ◽  
Javier Domingo-Diez ◽  
Miguel Rodriguez-Garcia ◽  
Oscar Garcia ◽  
Miroslav Vasic ◽  
...  

For decades now, conventional sinusoidal signals have been exclusively used in magnetic hyperthermia as the only alternating magnetic field waveform to excite magnetic nanoparticles. However, there are no theoretical nor experimental reasons that prevent the use of different waveforms. The only justifiable motive behind using the sinusoidal signal is its availability and the facility to produce it. Following the development of a configurable alternating magnetic field generator, we aim to study the effect of various waveforms on the heat production effectiveness of magnetic nanoparticles, seeking to prove that signals with more significant slope values, such as the trapezoidal and almost-square signals, allow the nanoparticles to reach higher efficiency in heat generation. Furthermore, we seek to point out that the nanoparticle power dissipation is dependent on the waveform’s slope and not only the frequency, magnetic field intensity and the nanoparticle size. The experimental results showed a remarkably higher heat production performance of the nanoparticles when exposed to trapezoidal and almost-square signals than conventional sinusoidal signals. We conclude that the nanoparticles respond better to the trapezoidal and almost-square signals. On the other hand, the experimental results were used to calculate the normalized power dissipation value and prove its dependency on the slope. However, adjustments are necessary to the coil before proceeding with in vitro and in vivo studies to handle the magnetic fields required.


Nanoscale ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 4103-4121
Author(s):  
Gabriele Barrera ◽  
Paolo Allia ◽  
Paola Tiberto

Dipolar interactions strongly modify effective heating power and the dynamical response regime of magnetic nanoparticles.


Nanoscale ◽  
2015 ◽  
Vol 7 (17) ◽  
pp. 7717-7725 ◽  
Author(s):  
M. Campanini ◽  
R. Ciprian ◽  
E. Bedogni ◽  
A. Mega ◽  
V. Chiesi ◽  
...  

Left: morphological and magnetic characterization of magnetite NPs. Right: Lorentz microscopy unveils the role of dipolar interactions in magnetic hyperthermia of superparamagnetic NPs.


2020 ◽  
Vol 22 (9) ◽  
Author(s):  
L. H. Nguyen ◽  
V. T. K. Oanh ◽  
P. H. Nam ◽  
D. H. Doan ◽  
N. X. Truong ◽  
...  

1991 ◽  
Vol 231 ◽  
Author(s):  
P. Bruno

AbstractTheoretical investigations of the magnetization and Curie temperature of ferromagnetic ultrathin films in the presence of magnetic anisotropy and long-range dipolar interactions are presented. The Curie temperature of fcc (001) cobalt ultrathin films is calculated and compared with experimental results on Co/Cu (001) films. The influence of an external magnetic field, and the surface gradient of the magnetization are also discussed.


Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1832 ◽  
Author(s):  
Ylenia Jabalera ◽  
Francesca Oltolina ◽  
Ana Peigneux ◽  
Alberto Sola-Leyva ◽  
Maria P. Carrasco-Jiménez ◽  
...  

The design of novel nanomaterials that can be used as multifunctional platforms allowing the combination of therapies is gaining increased interest. Moreover, if this nanomaterial is intended for a targeted drug delivery, the use of several guidance methods to increase guidance efficiency is also crucial. Magnetic nanoparticles (MNPs) allow this combination of therapies and guidance strategies. In fact, MNPs can be used simultaneously as drug nanocarriers and magnetic hyperthermia agents and, moreover, they can be guided toward the target by an external magnetic field and by their functionalization with a specific probe. However, it is difficult to find a system based on MNPs that exhibits optimal conditions as a drug nanocarrier and as a magnetic hyperthermia agent. In this work, a novel nanoformulation is proposed to be used as a multifunctional platform that also allows dual complementary guidance. This nanoformulation is based on mixtures of inorganic magnetic nanoparticles (M) that have been shown to be optimal hyperthermia agents, and biomimetic magnetic nanoparticles (BM), that have been shown to be highly efficient drug nanocarriers. The presence of the magnetosome protein MamC at the surface of BM confers novel surface properties that allow for the efficient and stable functionalization of these nanoparticles without the need of further coating, with the release of the relevant molecule being pH-dependent, improved by magnetic hyperthermia. The BM are functionalized with Doxorubicin (DOXO) as a model drug and with an antibody that allows for dual guidance based on a magnetic field and on an antibody. The present study represents a proof of concept to optimize the nanoformulation composition in order to provide the best performance in terms of the magnetic hyperthermia agent and drug nanocarrier.


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