scholarly journals Application of Magnetosomes in Magnetic Hyperthermia

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1320 ◽  
Author(s):  
Nikolai A. Usov ◽  
Elizaveta M. Gubanova
Keyword(s):  
Magnetic Field ◽  
Specific Absorption Rate ◽  
Magnetotactic Bacteria ◽  
Dipole Interaction ◽  
Magnetic Hyperthermia ◽  
Small Magnetic Field ◽  
Lifshitz Equation ◽  
Chain Axis ◽  
Rectangular Hysteresis Loop ◽  
A Chain

Nanoparticles, specifically magnetosomes, synthesized in nature by magnetotactic bacteria, are very promising to be usedin magnetic hyperthermia in cancer treatment. In this work, using the solution of the stochastic Landau–Lifshitz equation, we calculate the specific absorption rate (SAR) in an alternating (AC) magnetic field of assemblies of magnetosome chains depending on the particle size D, the distance between particles in a chain a, and the angle of the applied magnetic field with respect to the chain axis. The dependence of SAR on the a/D ratio is shown to have a bell-shaped form with a pronounced maximum. For a dilute oriented chain assembly with optimally chosen a/D ratio, a strong magneto-dipole interaction between the chain particles leads to an almost rectangular hysteresis loop, and to large SAR values in the order of 400–450 W/g at moderate frequencies f = 300 kHz and small magnetic field amplitudes H0 = 50–100 Oe. The maximum SAR value only weakly depends on the diameter of the nanoparticles and the length of the chain. However, a significant decrease in SAR occurs in a dense chain assembly due to the strong magneto-dipole interaction of nanoparticles of different chains.

scholarly journals Magnetotaxis as a Means for Nanofabrication

2014 ◽  
Vol 23 (01n02) ◽  
pp. 1450008
Author(s):  
Isaac Macwan ◽  
Zihe Zhao ◽  
Omar Sobh ◽  
Jinnque Rho ◽  
Ausif Mahmood ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Geomagnetic Field ◽  
Semiconductor Manufacturing ◽  
Magnetic Field Intensity ◽  
Magnetotactic Bacteria ◽  
Semiconductor Substrate ◽  
Field Lines ◽  
A Chain ◽  
Magnetospirillum Magneticum ◽  
The Magnetic Field

Magnetotactic bacteria (MTB), discovered in early 1970s contain single-domain crystals of magnetite ( Fe 3 O 4) called magnetosomes that tend to form a chain like structure from the proximal to the distal pole along the long axis of the cell. The ability of these bacteria to sense the magnetic field for displacement, also called magnetotaxis, arises from the magnetic dipole moment of this chain of magnetosomes. In aquatic habitats, these organisms sense the geomagnetic field and traverse the oxic-anoxic interface for optimal oxygen concentration along the field lines. Here we report an elegant use of MTB where magnetotaxis of Magnetospirillum magneticum (classified as AMB-1) could be utilized for controlled navigation over a semiconductor substrate for selective deposition. We examined 50mm long coils made out of 18AWG and 20AWG copper conductors having diameters of 5mm, 10mm and 20mm for magnetic field intensity and heat generation. Based on the COMSOL simulations and experimental data, it is recognized that a compound semiconductor manufacturing technology involving bacterial carriers and carbon-based materials such as graphene and carbon nanotubes would be a desirable choice in the future.

scholarly journals Towards Optimal Thermal Distribution in Magnetic Hyperthermia

2021 ◽  
Author(s):  
R. A. Rytov ◽  
V. A. Bautin ◽  
N. A. Usov
Keyword(s):  
Absorption Rate ◽  
Iron Nanoparticles ◽  
Specific Absorption Rate ◽  
Spatial Location ◽  
Dipole Interaction ◽  
Magnetic Hyperthermia ◽  
Spherically Symmetric ◽  
Heat Sources ◽  
Thermal Distribution ◽  
Suitable Temperature

Abstract A linear combination of spherically symmetric heat sources is shown to provide optimal stationary thermal distribution in magnetic hyperthermia. Furthermore, such spatial location of heat sources produces suitable temperature distribution in biological medium even for assemblies of magnetic nanoparticles with a moderate value of specific absorption rate (SAR), of the order of 100 - 150 W/g. We also demonstrate the advantage of using assemblies of magnetic nanocapsules consisting of metallic iron nanoparticles covered with non magnetic shells of sufficient thickness in magnetic hyperthermia. Based on numerical simulation we optimize the size and geometric structure of biocompatible capsules in order to minimize the influence of strong magneto-dipole interaction between closely spaced nanoparticles. It is shown that assembly of capsules can provide sufficiently high SAR values of the order of 250 - 400 W/g at moderate amplitudes H0·= 50 - 100 Oe and frequencies f = 100 - 200 kHz of alternating magnetic field, being appropriate for application in clinics.

scholarly journals Iron Oxide Nanoparticles for Magnetic Hyperthermia

SPIN ◽  
2019 ◽  
Vol 09 (02) ◽  
pp. 1940001 ◽  
Author(s):  
N. A. Usov
Keyword(s):  
Magnetic Field ◽  
Iron Oxide ◽  
Magnetic Nanoparticles ◽  
Iron Oxide Nanoparticles ◽  
Stochastic Equation ◽  
Sharp Decrease ◽  
Dipole Interaction ◽  
Magnetic Hyperthermia ◽  
Alternating Magnetic Field ◽  
Oxide Nanoparticles

Assemblies of magnetic nanoparticles show a great potential for application in biomedicine, particularly, magnetic hyperthermia. However, to achieve desired therapeutic effect in magnetic hyperthermia, the assembly of nanoparticles should have a sufficiently high specific absorption rate (SAR) in alternating magnetic field of moderate amplitude and frequency. Using the Landau–Lifshitz stochastic equation, it is shown that dilute assemblies of iron oxide nanoparticles of optimal diameters are capable of providing SAR of the order of 400–600[Formula: see text]W/g in alternating magnetic field with the amplitude [Formula: see text][Formula: see text]Oe in the frequency range f = 300–500[Formula: see text]kHz. Unfortunately, in dense clusters of magnetic nanoparticles, which are often formed in a biological medium, there is a sharp decrease in SAR due to the influence of strong magneto-dipole interaction of closest nanoparticles. To overcome this difficulty, it is suggested covering the nanoparticles with nonmagnetic shells of sufficient thickness or using non-single-domain nanoparticles being in magnetization curling states.

scholarly journals The Effect of Tissue-Mimicking Phantom Compressibility on Magnetic Hyperthermia

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 803 ◽  
Author(s):  
Katarzyna Kaczmarek ◽  
Radosław Mrówczyński ◽  
Tomasz Hornowski ◽  
Rafał Bielas ◽  
Arkadiusz Józefczak
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Magnetic Materials ◽  
Absorption Rate ◽  
Magnetic Particles ◽  
Specific Absorption Rate ◽  
Magnetic Hyperthermia ◽  
Magnetic Losses ◽  
Small Temperature ◽  
Transmission Electron

During hyperthermia, magnetite nanoparticles placed in an AC magnetic field become a source of heat. It has been shown that in fluid suspensions, magnetic particles move freely and generate heat easily. However, in tissues of different mechanical properties, nanoparticle movement is limited and leads to a small temperature rise in tissue. Therefore, it is crucial to conduct magnetic hyperthermia experiments in similar conditions to the human body. The effect of tissue-mimicking phantom compressibility on the effectiveness of magnetic hyperthermia was investigated on agar phantoms. Single and cluster nanoparticles were synthesized and used as magnetic materials. The prepared magnetic materials were characterized by transmission electron microscopy (TEM), and zeta potential measurements. Results show that tissue-mimicking phantom compressibility decreases with the concentration of agar. Moreover, the lower the compressibility, the lower the thermal effect of magnetic hyperthermia. Specific absorption rate (SAR) values also proved our assumption that tissue-mimicking phantom compressibility affects magnetic losses in the alternating magnetic field (AMF).

Long Magnetic Nanochains Assembled by Magnetotactic Bacteria in a Directional Field

2005 ◽  
Vol 475-479 ◽  
pp. 2411-2414
Author(s):  
X.L. Wu ◽  
W. Zhong ◽  
Shy Ying Gao ◽  
X.H. Qi ◽  
N.J. Tang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticles ◽  
External Magnetic Field ◽  
Magnetic Nanostructures ◽  
Magnetotactic Bacteria ◽  
Building Blocks ◽  
Directional Field ◽  
Live Bacteria ◽  
A Chain ◽  
Long Chains

A new species of single-cell magnetotactic bacteria, the NMV-1 bacteria, has been found by us. Each NMV-1 bacterium synthesizes itself a chain of magnetic nanoparticles inside its body. When an external magnetic field is applied, long bacteria chains come into being in the direction of the field in the water. More than 30 µm long chains of live bacteria have been observed. Length of bacteria chains is field dependant: the higher the magnetic field is, the longer the bacteria chains are. The bacteria chains orientation is controllable and the chains can be stably trapped. The mechanism of the assembly of long bacteria chains is also discussed. The results show that, while an external magnetic field is applied, the NMV-1 bacteria have strong enough interactions between each other to assemble long bacteria chains. After positioning the bacteria chain, cellular membranes of the bacteria were removed by cell lysis, leaving long chains of magnetic nanoparticles on a substrate. These magnetic nanochains can be potentially used as building blocks for magnetic nanostructures.

scholarly journals Angular Dependence of the Ferromagnetic Resonance Parameters of [Ti/FeNi]6/Ti/Cu/Ti/[FeNi/Ti]6 Nanostructured Multilayered Elements in the Wide Frequency Range

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 433
Author(s):  
Sergei V. Shcherbinin ◽  
Andrey V. Svalov ◽  
Grigory Y. Melnikov ◽  
Galina V. Kurlyandskaya
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Rf Sputtering ◽  
Magnetization Vector ◽  
Wide Frequency Range ◽  
Easy Magnetization ◽  
Magnetic Field Sensors ◽  
Magnetic Susceptibility Tensor ◽  
Small Magnetic Field ◽  
Lifshitz Equation

Magnetically soft [Ti(6)/FeNi(50)]6/Ti(6)/Cu(500)/Ti(6)/[FeNi(50)/Ti(6)]6 nanostructured multilayered elements were deposited by rf-sputtering technique in the shape of elongated stripes. The easy magnetization axis was oriented along the short size of the stripe using deposition in the external magnetic field. Such configuration is important for the development of small magnetic field sensors employing giant magnetoimpedance effect (GMI) for different applications. Microwave absorption of electromagnetic radiation was experimentally and theoretically studied in order to provide an as complete as possible high frequency characterization. The conductor-backed coplanar line was used for microwave properties investigation. The medialization for the precession of the magnetization vector in the uniformly magnetized GMI element was done on the basis of the Landau–Lifshitz equation with a dissipative Bloch–Bloembergen term. We applied the method of the complex amplitude for the analysis of the rotation of the ferromagnetic GMI element in the external magnetic field. The calculated and experimental dependences for the amplitudes of the imaginary part of the magnetic susceptibility tensor x-component and magnetoabsorption related to different angles show a good agreement.

scholarly journals Characterization of Bacterial Magnetotactic Behaviors by Using a Magnetospectrophotometry Assay

2009 ◽  
Vol 75 (12) ◽  
pp. 3835-3841 ◽  
Author(s):  
Christopher T. Lefèvre ◽  
Tao Song ◽  
Jean-Paul Yonnet ◽  
Long-Fei Wu
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Light Beam ◽  
Geomagnetic Field ◽  
Magnetic Particles ◽  
Magnetotactic Bacteria ◽  
Cell Alignment ◽  
The North ◽  
Field Lines ◽  
A Chain

ABSTRACT Magnetotactic bacteria have the unique capacity of synthesizing intracellular single-domain magnetic particles called magnetosomes. The magnetosomes are usually organized in a chain that allows the bacteria to align and swim along geomagnetic field lines, a behavior called magnetotaxis. Two mechanisms of magnetotaxis have been described. Axial magnetotactic cells swim in both directions along magnetic field lines. In contrast, polar magnetotactic cells swim either parallel to the geomagnetic field lines toward the North Pole (north seeking) or antiparallel toward the South Pole (south seeking). In this study, we used a magnetospectrophotometry (MSP) assay to characterize both the axial magnetotaxis of “Magnetospirillum magneticum” strain AMB-1 and the polar magnetotaxis of magneto-ovoid strain MO-1. Two pairs of Helmholtz coils were mounted onto the cuvette holder of a common laboratory spectrophotometer to generate two mutually perpendicular homogeneous magnetic fields parallel or perpendicular to the light beam. The application of magnetic fields allowed measurements of the change in light scattering resulting from cell alignment in a magnetic field or in absorbance due to bacteria swimming across the light beam. Our results showed that MSP is a powerful tool for the determination of bacterial magnetism and the analysis of alignment and swimming of magnetotactic bacteria in magnetic fields. Moreover, this assay allowed us to characterize south-seeking derivatives and non-magnetosome-bearing strains obtained from north-seeking MO-1 cultures. Our results suggest that oxygen is a determinant factor that controls magnetotactic behavior.

Fe2O3 nanoparticles for magnetic hyperthermia applications

2015 ◽  
Vol 1779 ◽  
pp. 7-13 ◽  
Author(s):  
O M Lemine ◽  
Karim Omri ◽  
L El Mir ◽  
V Velasco ◽  
Patricia Crespo ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Magnetic Hyperthermia ◽  
Fe2o3 Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heating Efficiency ◽  
Hall Method

ABSTRACTSynthesis, structural, magnetic properties and heating efficiency of γ-Fe2O3 nanoparticles have been investigated. X-ray diffraction (XRD) and Mössbauer spectroscopy show that the obtained nanoparticles are mainly composed of maghemite phase (γ-Fe2O3). Williamson-Hall method shows that the crystallite is around 14nm.The specific absorption rate (SAR) under an alternating magnetic field is investigated as a function of frequency. A highest SAR value of 12W/g for frequency 523 kHz was obtained.

scholarly journals All organic multiferroic magnetoelectric complexes with strong interfacial spin-dipole interaction

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Yuying Yang ◽  
Zhiyan Chen ◽  
Xiangqian Lu ◽  
Xiaotao Hao ◽  
Wei Qin
Keyword(s):  
Magnetic Field ◽  
Light Intensity ◽  
Room Temperature ◽  
Incident Light ◽  
Dipole Interaction ◽  
Interfacial Interaction ◽  
Magnetoelectric Coupling ◽  
Incident Light Intensity ◽  
Organic Ferromagnets ◽  
Magnetoelectric Coefficient

AbstractThe organic magnetoelectric complexes are beneficial for the development on flexible magnetoelectric devices in the future. In this work, we fabricated all organic multiferroic ferromagnetic/ferroelectric complexes to study magnetoelectric coupling at room temperature. Under the stimulus of external magnetic field, the localization of charge inside organic ferromagnets will be enhanced to affect spin–dipole interaction at organic multiferroic interfaces, where overall ferroelectric polarization is tuned to present an organic magnetoelectric coupling. Moreover, the magnetoelectric coupling of the organic ferromagnetic/ferroelectric complex is tightly dependent on incident light intensity. Decreasing light intensity, the dominated interfacial interaction will switch from spin–dipole to dipole–dipole interaction, which leads to the magnetoelectric coefficient changing from positive to negative in organic multiferroic magnetoelectric complexes.

scholarly journals Heat induction in two-dimensional graphene–Fe3O4 nanohybrids for magnetic hyperthermia applications with artificial neural network modeling

RSC Advances ◽  
2021 ◽  
Vol 11 (35) ◽  
pp. 21702-21715
Author(s):  
M. S. Dar ◽  
Khush Bakhat Akram ◽  
Ayesha Sohail ◽  
Fatima Arif ◽  
Fatemeh Zabihi ◽  
...  
Keyword(s):  
Neural Network ◽  
Magnetic Field ◽  
Artificial Neural Network ◽  
Network Modeling ◽  
Magnetic Hyperthermia ◽  
Alternating Magnetic Field ◽  
Neural Network Modeling ◽  
Two Dimensional ◽  
Artificial Neural Network Modeling ◽  
Heat Induction

Synthesis of Fe3O4–graphene (FG) nanohybrids and magnetothermal measurements of FxG100–x (x = 0, 25, 45, 65, 75, 85, 100) nanohybrids (25 mg each) at a 633 kHz alternating magnetic field of strength 9.1 mT.

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