Self-controlled Magnetic Hyperthermia Research Articles

Improvement of the Self-Controlled Hyperthermia Applications by Varying Gadolinium Doping in Lanthanum Strontium Manganite Nanoparticles

In this study, silica-encapsulated gadolinium was doped in lanthanum strontium manganite nanoparticles (NPs) with different concentrations using the citrate–gel auto-combustion method. We focused on tuning the Curie temperature and enhancing the specific absorption rate (SAR) of silica-coated gadolinium-doped lanthanum strontium manganite NPs to make them suitable for self-controlled magnetic hyperthermia. The samples were characterized by using transmission electron microscopy (TEM), X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), and magnetic measurements to examine the structural, optical, and magnetic properties of the manganite NPs. While our results exhibit a successful doping of gadolinium in lanthanum strontium manganite NPs, we further prepared magnetic core NPs with sizes between 20 and 50 nm. The Curie temperature of the NPs declined with increasing gadolinium doping, making them promising materials for hyperthermia applications. The Curie temperature was measured using the magnetization (M-T) curve. Magnetic heating was carried out in an external applied AC magnetic field. Our present work proved the availability of regulating the Curie temperature of gadolinium-doped lanthanum strontium manganite NPs, which makes them promising candidates for self-controlled magnetic hyperthermia applications.

Application of Ion‐Doped Y3Fe5O12 Nanoparticles for Self‐Controlled Magnetic Hyperthermia

Herein, doped yttrium garnet (YIG) nanoparticles (NPs) ( Al, Ga, Sc are nonmagnetic ions) are studied, appropriate for self‐controlled magnetic hyperthermia (SCMH) for in vivo and in vitro applications. A microscopic model (modified Heisenberg Hamiltonian) and the Green's function technique are used to investigate the temperature, doping, and size dependence of magnetic phase transition, saturation magnetization, the coercivity, and the specific absorption rate coefficient to fulfill the conditions for magnetic hyperthermia. A set of mixed yttrium garnet magnetic NPs is found, which are suitable for applications in medicine for cancer therapy. There are two Sc‐doped YIG NPs which are the best candidates for SCMH with x = 1.08, d = 27.5 nm, and = 13.52 as well as x = 1.10, d = 29.7 nm, and = 15.44 for which the conditions for biocompatibility and maximization of are fulfilled simultaneously. Moreover, also Al‐ and Ga‐doped YIG NPs are found that can be applied for magnetic hyperthermia but with smaller effectivity.

Microscopic theory of the specific absorption rate for self-controlled magnetic hyperthermia

Despite the efforts of many research teams, to optimize the process of thermal heating of magnetic nanoparticles interacting with an alternating magnetic field for self-controlled magnetic hyperthermia remains a challenge. Macroscopic models that quantify the process of heat generation could not combine the biocompatibility requirements of magnetic nanoparticles in human medicine on one hand with high values of specific absorption rate (SAR) on the other. For the first time, we propose a microscopic model using Kubo formalism, a modified Heisenberg Hamiltonian and the method of Green's functions for calculating the absorbed power (thermal energy absorbed by a magnetic nanoparticle per unit time in an alternating magnetic field). From the observed transverse magnetic susceptibility, elementary excitation energy, and damping is investigated the SAR as a function of the microscopic parameters of the systems: exchange interaction constants and single-ion magnetic anisotropy. The calculations are made for a magnetic complex heterogeneous nanoparticle consisting of core, shell, intermediate layer between them, and surface (the so called core/shell model). The proposed nanoparticle model allows for each region to define different exchange interaction and magnetic anisotropy constants as well as different magnetic configurations and thickness. The dependence of SAR on the microscopic parameters of the system is analyzed and qualitatively explained by the behavior of the elementary excitations (spin energy and damping). The results are in good qualitative agreement with the experimental data and show that using complex magnetic nanoparticles the heating properties for hyperthermia could be maximized.

Specific absorption rate in Zn-doted ferrites for self-controlled magnetic hyperthermia

In this paper, we study mixed ferrites nanoparticles with structure formula Me1−xZnxFe2O4 (Me = Co, Ni, Cu, Mn) appropriated for self-controlled magnetic hyperthermia (SMHT) for in vivo and in vitro applications. We discuss in details the influence of the size d, the Zn-ion concentration x on the magnetic characteristics: saturation magnetization MS, coercivity HC, effective anisotropy Keff and specific absorption rate (SAR). From a theoretical point of view we investigate monodispersed, non-interactive, single-domain spherical magnetic nanoparticles (MNPs). We propose a simple core–shell model with a constant thickness of the surface layer. We explain the behaviour of SAR as a function of size and dopping based on two thermal heating mechanisms: the mechanism leading to dynamic hysteresis loops of superparamagnetic origin and the heating mechanism via conventional metastable hysteresis. We investigate also a thermal heating efficiency based on the Zn-ion concentration. We show that whether SAR decreases (increases) when doping increases depends on whether the nanoparticle diameter d is smaller (larger) than the particle size dmax for which SAR has a maximum value. The numerical results are in qualitative agreement with many experimental data.

Nickel-zinc spinel nanoferrites: Magnetic characterization and prospects of the use in self-controlled magnetic hyperthermia

Abstract Effect of zinc substitution on magnetic properties and AC heating characteristics of Ni1−xZnxFe2O4 (x = 0–1) nanoparticles has been studied. Magnetic parameters, such as saturation magnetization, Curie temperature, specific loss power, have been determined for the samples. It is shown that the samples with a higher zinc concentration (x > 0.5) display reduced values of spontaneous magnetization and Curie temperature as compared to those with x

Influence of crystallite size on the magnetic and heat generation properties of La0.77Sr0.23MnO3 nanoparticles for hyperthermia applications

In this paper, we report a detailed study of magnetic properties and AC magnetic heat generation characteristics of La0.77Sr0.23MnO3 (LSMO) nanoparticles to investigate appropriate crystallite size with a view to the proper application of self-controlled magnetic hyperthermia treatments of cancer. A series of nanocrystalline LSMO manganite was synthesized through the chemical route called as “polymerized complex method” and then subsequently annealed at the different temperature from 600 to 1400 °C to obtain various crystallite size. Phase formation and crystal structure of the prepared powder were determined by the powder X-ray diffraction (XRD) using Rietveld analysis. The XRD patterns reveal that all powder samples are a single phase rhombohedral perovskite-like structure with R3¯c space group. The mean crystallite size of prepared particles varied from 19 to 243.8 nm with the increase of the annealing temperature starting from 600 to 1400 °C. The field emission scanning electron microscopy (FE-SEM) analysis shows the surface morphology with a strong agglomeration of fine nanoparticles. The Magnetic study reveals that these nanoparticles exhibit ferromagnetic nature with different value of magnetization, coercivity, Curie temperature which is strongly dependent on their crystallite size. The maximum saturation temperature (TS = 66 °C) under AC magnetic field (H = 1.77 kA/m, f = 370 kHz) was found for the crystallite size of 39.5 nm due to its pure single domain phase. Such LSMO nanoparticles, having the higher heating rate, can be used in magnetically induced hyperthermia cancer treatment.

Ferrimagnetic nanoparticles for self-controlled magnetic hyperthermia

Based on the Heisenberg model including single-site uniaxial anisotropy and using a Green’s function technique we studied the influence of size and composition effects on the Curie temperature T C , saturation magnetization M S and coercivity H C of spherical nanoparticles with a structural formula M e 1−x Zn x Fe2O4, Me = Ni, Cu, Co, Mn. It is shown that for x = 0.4–0.5 and d = 10–20 nm these nanoparticles have a T C = 315 K and are suitable for a self-controlled magnetic hyperthermia.

MnZnFe nanoparticles for self-controlled magnetic hyperthermia

Manganese zinc iron magnetic nanoparticles were synthesized by a co-precipitation method for application as hyperthermia inducing agents. The structure, morphology and magnetic properties of the nanoparticles are characterized using scanning electron microscopy, X-ray diffraction, and a superconducting quantum interference device. The magnetic properties being investigated include Curie temperature, saturation magnetization, remnant magnetization, coercive field, and hysteresis. The study showed that adjusting the Mn contribution to the particles contributed to the adjustment of all magnetic properties of the complex.

MO.Fe2O3 nanoparticles for self-controlled magnetic hyperthermia

Using a model Hamiltonian and the Green’s function technique for the Zn doped Mn-ferrite, Mn1-xZnxO.Fe2O3, and the Gd doped Zn-ferrite, ZnGdxFe(2-x)O4, nanoparticles of different compositions x were studied. The phase transition temperature, TC, and the coercive field, Hc, for different samples dependent upon composition, particle size, and shape were investigated. An attempt was made to enhance or to lower the TC of the nanoparticles to the optimum temperature required in magnetic hyperthermia (42–43°C).