Sinusoidal magnetic field stimulates magnetosome formation and affects mamA, mms13, mms6, and magA expression in Magnetospirillum magneticum AMB-1

Magnetic particles are currently one of the most important materials in the industrial sector, where they have been widely used for biotechnological and biomedical applications. To investigate the effects of the imposed magnetic field on biomineralization in Magnetospirillum magneticum AMB-1 and to suggest a new approach that enhances formation of magnetosomes, cultures inoculated with either magnetic or nonmagnetic precultures were incubated under a sinusoidal magnetic field or geomagnetic field. The results showed that the sinusoidal magnetic field up-regulated mms6 expression in the cultures inoculated with magnetic cells, and magA, mms6, and mamA expression in the cultures inoculated with nonmagnetic cells. The applied sinusoidal magnetic field could block cell division, which could contribute to a decrease in the OD600 values and an increase in the coefficient of magnetism values of the cultures, which could mean that the percentage of mature magnetosome-containing bacteria was increased. The linearity of magnetosome chains was affected, but the number of magnetic particles in cells was increased when a sinusoidal magnetic field was applied to the cultures. The results imply that the variable intensity and orientation of the sinusoidal magnetic field resulted in magnetic pole conversion in the newly forming magnetic particles, which could affect the formation of magnetic crystals and the arrangement of the adjacent magnetosome.

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Magnetotaxis as a Means for Nanofabrication

International Journal of High Speed Electronics and Systems ◽

10.1142/s0129156414500086 ◽

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.

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The Application of Carbon Nanotubes in Magnetic Fluid Hyperthermia

Journal of Nanomaterials ◽

10.1155/2015/527652 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 8

Author(s):

Grzegorz Raniszewski ◽

Arkadiusz Miaskowski ◽

Slawomir Wiak

Keyword(s):

Magnetic Field ◽

Carbon Nanotubes ◽

Biomedical Applications ◽

Magnetic Particles ◽

Damage Model ◽

Alternating Magnetic Field ◽

Thermal Dose ◽

Generation Efficiency ◽

Magnetic Fluid Hyperthermia ◽

Body Tissues

The aim of this paper is to present the results of the investigation into the applications of carbon nanotubes with ferromagnetic nanoparticles as nanoheaters for targeted thermal ablation of cancer cells. Relevant nanoparticles’ characteristics were exploited in terms of their functionality for biomedical applications and their magnetic properties were examined to determine heat generation efficiency induced by the exposure of the particles to an alternating magnetic field. The influence of the electromagnetic field on the human body tissues was assessed, providing quantitative measures of the interaction. The behavior of a liquid containing magnetic particles, during the exposure to the alternating magnetic field, was verified. As for the application for the ferromagnetic carbon nanotubes, the authors investigated temperature distribution in human liver tumor together with Arrhenius tissue damage model and the thermal dose concept.

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Characterization of Bacterial Magnetotactic Behaviors by Using a Magnetospectrophotometry Assay

Applied and Environmental Microbiology ◽

10.1128/aem.00165-09 ◽

2009 ◽

Vol 75 (12) ◽

pp. 3835-3841 ◽

Cited By ~ 31

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.

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Efficient and Stable Display of Functional Proteins on Bacterial Magnetic Particles Using Mms13 as a Novel Anchor Molecule

Applied and Environmental Microbiology ◽

10.1128/aem.72.1.465-471.2006 ◽

2006 ◽

Vol 72 (1) ◽

pp. 465-471 ◽

Cited By ~ 82

Author(s):

Tomoko Yoshino ◽

Tadashi Matsunaga

Keyword(s):

Biomedical Applications ◽

Magnetic Particles ◽

Protein A ◽

Bilayer Membrane ◽

Large Protein ◽

C Terminus ◽

Transmission Electron ◽

Antibody Complex ◽

Bacterial Magnetic Particles ◽

Magnetospirillum Magneticum

ABSTRACT Magnetic particles are increasingly used for various biomedical applications because they are easy to handle and separate from biological samples. In this work, a novel anchor molecule was used for targeted protein display onto magnetic nanoparticles. The magnetic bacterium Magnetospirillum magneticum AMB-1 synthesizes intracellular bacterial magnetic particles (BMPs) covered with a lipid bilayer membrane. In our recent research, an integral BMP membrane protein, Mms13, was isolated and used as an anchor molecule to display functional proteins onto BMPs. The anchoring properties of Mms13 were confirmed by luciferase fusion studies. The C terminus of Mms13 was shown to be expressed on the surface of BMPs, and Mms13 was bound to magnetite directly and tightly permitting stable localization of a large protein, luciferase (61 kDa), on BMPs. Consequently, luminescence intensity obtained from BMPs using Mms13 as an anchor molecule was >400 or 1,000 times higher than Mms16 or MagA, which previously were used as anchor molecules. Furthermore, the immunoglobulin G-binding domain of protein A (ZZ) was displayed uniformly on BMPs using Mms13, and antigen was detected by transmission electron microscopy using antibody-labeled gold nanoparticles on a single BMP displaying the ZZ-antibody complex. The results of this study demonstrated the utility of Mms13 as a molecular anchor, which will facilitate the assembly of other functional proteins onto BMPs in the near feature.

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Investigation of Magnetic Nanoparticle Motion under a Gradient Magnetic Field by an Electromagnet

Journal of Nanomaterials ◽

10.1155/2018/6246917 ◽

2018 ◽

Vol 2018 ◽

pp. 1-5 ◽

Cited By ~ 3

Author(s):

Weizhong Wei ◽

Zhen Wang

Keyword(s):

Magnetic Field ◽

Finite Element ◽

Electromagnetic Field ◽

Magnetic Nanoparticles ◽

Particle Motion ◽

Biomedical Applications ◽

Magnetic Nanoparticle ◽

Magnetic Particles ◽

Magnetic Force ◽

Gradient Magnetic Field

Finite element numerical simulations were carried out in 2D geometry to calculate the magnetic force on magnetic nanoparticles under a specially fabricated electromagnet. The particle motion was modeled by a system of ordinary differential equations. The snapshots of trajectories of 4000 MNPs with and without magnetic field were analyzed and qualitatively found to be in agreement with camera visualizations of MNP movement in a container. The results of the analysis could be helpful for the design of electromagnetic field and motion analysis of magnetic particles for the delivery of magnetic materials in biomedical applications.

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Analysis of magneto rheological elastomers for energy harvesting systems

International Journal of Applied Electromagnetics and Mechanics ◽

10.3233/jae-209350 ◽

2020 ◽

Vol 64 (1-4) ◽

pp. 439-446

Author(s):

Gildas Diguet ◽

Gael Sebald ◽

Masami Nakano ◽

Mickaël Lallart ◽

Jean-Yves Cavaillé

Keyword(s):

Magnetic Field ◽

Energy Harvesting ◽

Shear Strain ◽

Magnetic Induction ◽

Magnetic Particles ◽

Homogeneous Magnetic Field ◽

Electrical Signal ◽

Harvesting Systems ◽

Dc Bias ◽

Magneto Rheological

Magneto Rheological Elastomers (MREs) are composite materials based on an elastomer filled by magnetic particles. Anisotropic MRE can be easily manufactured by curing the material under homogeneous magnetic field which creates column of particles. The magnetic and elastic properties are actually coupled making these MREs suitable for energy conversion. From these remarkable properties, an energy harvesting device is considered through the application of a DC bias magnetic induction on two MREs as a metal piece is applying an AC shear strain on them. Such strain therefore changes the permeabilities of the elastomers, hence generating an AC magnetic induction which can be converted into AC electrical signal with the help of a coil. The device is simulated with a Finite Element Method software to examine the effect of the MRE parameters, the DC bias magnetic induction and applied shear strain (amplitude and frequency) on the resulting electrical signal.

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How to Improve Physico-Chemical Properties of Silk Fibroin Materials for Biomedical Applications?—Blending and Cross-Linking of Silk Fibroin—A Review

Materials ◽

10.3390/ma14061510 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1510

Author(s):

Sylwia Grabska-Zielińska ◽

Alina Sionkowska

Keyword(s):

Silk Fibroin ◽

Biomedical Applications ◽

Magnetic Particles ◽

Chemical Properties ◽

Ternary Mixtures ◽

Cross Linking ◽

Advantages And Disadvantages ◽

Physico Chemical ◽

Binary And Ternary Mixtures ◽

To Receive

This review supplies a report on fresh advances in the field of silk fibroin (SF) biopolymer and its blends with biopolymers as new biomaterials. The review also includes a subsection about silk fibroin mixtures with synthetic polymers. Silk fibroin is commonly used to receive biomaterials. However, the materials based on pure polymer present low mechanical parameters, and high enzymatic degradation rate. These properties can be problematic for tissue engineering applications. An increased interest in two- and three-component mixtures and chemically cross-linked materials has been observed due to their improved physico-chemical properties. These materials can be attractive and desirable for both academic, and, industrial attention because they expose improvements in properties required in the biomedical field. The structure, forms, methods of preparation, and some physico-chemical properties of silk fibroin are discussed in this review. Detailed examples are also given from scientific reports and practical experiments. The most common biopolymers: collagen (Coll), chitosan (CTS), alginate (AL), and hyaluronic acid (HA) are discussed as components of silk fibroin-based mixtures. Examples of binary and ternary mixtures, composites with the addition of magnetic particles, hydroxyapatite or titanium dioxide are also included and given. Additionally, the advantages and disadvantages of chemical, physical, and enzymatic cross-linking were demonstrated.

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Predictions of the geomagnetic secular variation based on the ensemble sequential assimilation of geomagnetic field models by dynamo simulations

Earth Planets and Space ◽

10.1186/s40623-020-01279-y ◽

2020 ◽

Vol 72 (1) ◽

Author(s):

Sabrina Sanchez ◽

Johannes Wicht ◽

Julien Bärenzung

Keyword(s):

Magnetic Field ◽

Secular Variation ◽

Geomagnetic Field ◽

Wave Number ◽

Main Magnetic Field ◽

Candidate Model ◽

Uncertainty Estimates ◽

Geomagnetic Field Models ◽

Dipole Configuration

Abstract The IGRF offers an important incentive for testing algorithms predicting the Earth’s magnetic field changes, known as secular variation (SV), in a 5-year range. Here, we present a SV candidate model for the 13th IGRF that stems from a sequential ensemble data assimilation approach (EnKF). The ensemble consists of a number of parallel-running 3D-dynamo simulations. The assimilated data are geomagnetic field snapshots covering the years 1840 to 2000 from the COV-OBS.x1 model and for 2001 to 2020 from the Kalmag model. A spectral covariance localization method, considering the couplings between spherical harmonics of the same equatorial symmetry and same azimuthal wave number, allows decreasing the ensemble size to about a 100 while maintaining the stability of the assimilation. The quality of 5-year predictions is tested for the past two decades. These tests show that the assimilation scheme is able to reconstruct the overall SV evolution. They also suggest that a better 5-year forecast is obtained keeping the SV constant compared to the dynamically evolving SV. However, the quality of the dynamical forecast steadily improves over the full assimilation window (180 years). We therefore propose the instantaneous SV estimate for 2020 from our assimilation as a candidate model for the IGRF-13. The ensemble approach provides uncertainty estimates, which closely match the residual differences with respect to the IGRF-13. Longer term predictions for the evolution of the main magnetic field features over a 50-year range are also presented. We observe the further decrease of the axial dipole at a mean rate of 8 nT/year as well as a deepening and broadening of the South Atlantic Anomaly. The magnetic dip poles are seen to approach an eccentric dipole configuration.

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Design of a New 1D Halbach Magnet Array with Good Sinusoidal Magnetic Field by Analyzing the Curved Surface

Sensors ◽

10.3390/s21072522 ◽

2021 ◽

Vol 21 (7) ◽

pp. 2522

Author(s):

Guangdou Liu ◽

Shiqin Hou ◽

Xingping Xu ◽

Wensheng Xiao

Keyword(s):

Magnetic Field ◽

Magnetic Flux ◽

Permanent Magnet ◽

Flux Density ◽

Permanent Magnets ◽

Air Gap ◽

Curved Surface ◽

Magnetic Flux Density ◽

Sinusoidal Magnetic Field ◽

The Magnetic Field

In the linear and planar motors, the 1D Halbach magnet array is extensively used. The sinusoidal property of the magnetic field deteriorates by analyzing the magnetic field at a small air gap. Therefore, a new 1D Halbach magnet array is proposed, in which the permanent magnet with a curved surface is applied. Based on the superposition of principle and Fourier series, the magnetic flux density distribution is derived. The optimized curved surface is obtained and fitted by a polynomial. The sinusoidal magnetic field is verified by comparing it with the magnetic flux density of the finite element model. Through the analysis of different dimensions of the permanent magnet array, the optimization result has good applicability. The force ripple can be significantly reduced by the new magnet array. The effect on the mass and air gap is investigated compared with a conventional magnet array with rectangular permanent magnets. In conclusion, the new magnet array design has the scalability to be extended to various sizes of motor and is especially suitable for small air gap applications.

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