scholarly journals Programmable Shunt Valves: In Vitro Assessment of Safety of the Magnetic Field Generated by a Portable Game Machine

2011 ◽  
Vol 51 (9) ◽  
pp. 635-638 ◽  
Author(s):  
Koji NAKASHIMA ◽  
Takato NAKAJO ◽  
Michiari KAWAMO ◽  
Akihito KATO ◽  
Seiichiro ISHIGAKI ◽  
...  
Keyword(s):  
Magnetic Field ◽  
In Vitro Assessment ◽  
The Magnetic Field

In Vitro Evaluation of Capturing and Dissolving the Clot by Magnetic Nanoparticles Carrying a Thrombolytic Agents Instead of Temporary Inferior Vena Cava (IVC) Filter

2020 ◽  
Vol 16 (11) ◽  
pp. 1623-1632
Author(s):  
Abbas Moghanizadeh ◽  
Fakhreddin Ashrafizadeh ◽  
Jaleh Varshousaz ◽  
Mahshid Kharaziha
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticles ◽  
Vena Cava ◽  
Simple Method ◽  
Thrombolytic Agents ◽  
Blood Clots ◽  
Life Threatening ◽  
The Magnetic Field ◽  
Different Levels

This study aims to evaluate the efficiency of a novel in vitro technique in clot capturing and dissolving them by applying magnetic force on magnetic nanoparticles (MNP) carrying thrombolytic agents. It is a quick and simple method to protect patients from a life-threatening pulmonary embolism in an emergency to provide time for the medical team. To analyze the in vitro efficiency of nano-magnetic capturing and dissolving of clots (NCDC), different levels of process parameter including strength magnetic field (0.1, 0.2 and 0.3 T) and fluid flow rate (2.5, 5 and 7 l/min) are exposed to different blood clots sizes from 5 × 10 to 20 × 10 mm2 (length × diameter), in an in vitro flow model. The results show that by increasing the parameters to their maximum values, it is possible to immobilize 100% of the clots and dissolve around 61.4% of clots weight. In addition, the clot-dissolving is directly proportional to the magnetic field strength. NCDC is an efficient technique in immobilizing and dissolving the clots and its efficiency depends on process parameters especially the magnetic field.

scholarly journals Remote manipulation of magnetic nanoparticles using magnetic field gradient to promote cancer cell death

2018 ◽  
Author(s):  
Mahendran Subramanian ◽  
Arkadiusz Miaskowski ◽  
Stuart Iain Jenkins ◽  
Jenson Lim ◽  
Jon Dobson
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticles ◽  
Field Gradient ◽  
Biomedical Applications ◽  
Magnetic Field Gradient ◽  
Field Source ◽  
Remote Manipulation ◽  
Cancer Cell Death ◽  
The Magnetic Field

AbstractThe manipulation of magnetic nanoparticles (MNPs) using an external magnetic field, has been demonstrated to be useful in various biomedical applications. Some techniques have evolved utilizing this non-invasive external stimulus but the scientific community widely adopts few, and there is an excellent potential for more novel methods. The primary focus of this study is on understanding the manipulation of MNPs by a time-varying static magnetic field and how this can be used, at different frequencies and displacement, to manipulate cellular function. Here we explore, using numerical modeling, the physical mechanism which underlies this kind of manipulation, and we discuss potential improvements which would enhance such manipulation with its use in biomedical applications, i.e., increasing the MNP response by improving the field parameters. From our observations and other related studies, we infer that such manipulation depends mostly on the magnetic field gradient, the magnetic susceptibility and size of the MNPs, the magnet array oscillating frequency, the viscosity of the medium surrounding MNPs, and the distance between the magnetic field source and the MNPs. Additionally, we demonstrate cytotoxicity in neuroblastoma (SH-SY5Y) and hepatocellular carcinoma (HepG2) cells in vitro. This was induced by incubation with MNPs, followed by exposure to a magnetic field gradient, physically oscillating at various frequencies and displacement amplitudes. Even though this technique reliably produces MNP endocytosis and/or cytotoxicity, a better biophysical understanding is required to develop the mechanism used for this precision manipulation of MNPs, in vitro.

Arg-Gly-Asp Peptide-Functionalized Superparamagnetic γ-Fe2O3 Nanoparticles Enhance Osteoblast Migration In Vitro

2020 ◽  
Vol 20 (10) ◽  
pp. 6173-6179
Author(s):  
Xue Liu ◽  
Xiao-Ling Yang ◽  
Qiao Hu ◽  
Mao-Shi Liu ◽  
Tao Peng ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Cell Therapy ◽  
Bone Repair ◽  
Cartilage Regeneration ◽  
Uniform Size ◽  
Low Cytotoxicity ◽  
The Magnetic Field ◽  
And Cartilage ◽  
Osteoblast Migration

Making osteoblast migration manageably target to injury sites has been the key challenging in cell therapy for bone and cartilage regeneration. Superparamagnetic materials, the magnetic guide for cell migration, have been applied to increase cell retention. However, additional targeting modifications are still needed to accelerate the low uptake efficiency and moving speed. Arg-Gly-Asp peptide (RGD)-functionalized magnetic nanoparticles showed cutting-edge competence in cell differentiation control and targeted drug delivery. However, more evidence was required to corroborate its role in osteoblast migration in bone repair. In the present study, RGD-modified γ-Fe2O3 nanoparticles (RGD-Fe2O3 NPs) were prefabricated with the grafting ratio of 33.3–37.4%. The RGD-Fe2O3 NPs unveiled excellent water dispersibility with uniform size distribution at 5–6 nm and negligibly low cytotoxicity. As a result, MC3T3-E1 osteoblasts treated with RGD-Fe2O3 NPs boosted its migration speed in a magnetic field compared with those incubated with unmodified Fe2O3 NPs. Furthermore, osteoblasts treated with RGD-Fe2O3 NPs exhibited more Fe uptake. The results exposed the fact that RGD-mediated specific cellular uptake presented higher efficiency than the non-RGD-mediated one, resulting from a stronger superparamagnetic force between the labeled cells and the magnetic field. These findings indicate that the RGD-functionalized Fe2O3 NPs can promote osteoblast migration in the magnetic field, providing a promising strategy in magnet-guided cell therapy for bone and cartilage regeneration.

A Role for the magnetic field in the radiation-induced efflux of calcium ions from brain tissue in vitro

1985 ◽  
Vol 6 (4) ◽  
pp. 327-337 ◽  
Author(s):  
C. F. Blackman ◽  
S. G. Benane ◽  
J. R. Rabinowitz ◽  
D. E. House ◽  
W. T. Joines
Keyword(s):  
Magnetic Field ◽  
Brain Tissue ◽  
Calcium Ions ◽  
Radiation Induced ◽  
The Magnetic Field

scholarly journals Magnetic Field Dynamic Strategies for the Improved Control of the Angiogenic Effect of Mesenchymal Stromal Cells

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1883
Author(s):  
Ana C. Manjua ◽  
Joaquim M. S. Cabral ◽  
Frederico Castelo Ferreira ◽  
Carla A. M. Portugal
Keyword(s):  
Magnetic Field ◽  
Cancer Progression ◽  
Mesenchymal Stromal Cells ◽  
Field Intensity ◽  
Stromal Cells ◽  
Magnetic Field Intensity ◽  
Therapeutic Option ◽  
Angiogenic Effect ◽  
The Magnetic Field

This work shows the ability to remotely control the paracrine performance of mesenchymal stromal cells (MSCs) in producing an angiogenesis key molecule, vascular endothelial growth factor (VEGF-A), by modulation of an external magnetic field. This work compares for the first time the application of static and dynamic magnetic fields in angiogenesis in vitro model, exploring the effect of magnetic field intensity and dynamic regimes on the VEGF-A secretion potential of MSCs. Tissue scaffolds of gelatin doped with iron oxide nanoparticles (MNPs) were used as a platform for MSC proliferation. Dynamic magnetic field regimes were imposed by cyclic variation of the magnetic field intensity in different frequencies. The effect of the magnetic field intensity on cell behavior showed that higher intensity of 0.45 T was associated with increased cell death and a poor angiogenic effect. It was observed that static and dynamic magnetic stimulation with higher frequencies led to improved angiogenic performance on endothelial cells in comparison with a lower frequency regime. This work showed the possibility to control VEGF-A secretion by MSCs through modulation of the magnetic field, offering attractive perspectives of a non-invasive therapeutic option for several diseases by revascularizing damaged tissues or inhibiting metastasis formation during cancer progression.

scholarly journals Analysis of the Magnetic Field Influence on the Rheological Properties of Healthy Persons Blood

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Anna Marcinkowska-Gapinska ◽  
Honorata Nawrocka-Bogusz
Keyword(s):  
Magnetic Field ◽  
Rheological Properties ◽  
Blood Viscosity ◽  
Flow Curve ◽  
Rheological Parameters ◽  
Blood Samples ◽  
The Magnetic Field ◽  
Field Influence ◽  
Healthy Persons

The influence of magnetic field on whole blood rheological properties remains a weakly known phenomenon. Anin vitroanalysis of the magnetic field influence on the rheological properties of healthy persons blood is presented in this work. The study was performed on blood samples taken from 25 healthy nonsmoking persons and included comparative analysis of the results of both the standard rotary method (flow curve measurement) and the oscillatory method known also as the mechanical dynamic analysis, performed before and after exposition of blood samples to magnetic field. The principle of the oscillatory technique lies in determining the amplitude and phase of the oscillations of the studied sample subjected to action of a harmonic force of controlled amplitude and frequency. The flow curve measurement involved determining the shear rate dependence of blood viscosity. The viscoelastic properties of the blood samples were analyzed in terms of complex blood viscosity. All the measurements have been performed by means of the Contraves LS40 rheometer. The data obtained from the flow curve measurements complemented by hematocrit and plasma viscosity measurements have been analyzed using the rheological model of Quemada. No significant changes of the studied rheological parameters have been found.

On-line measurement of aortic valve ring deformation during the cardiac cycle

1988 ◽  
Vol 254 (4) ◽  
pp. H795-H800
Author(s):  
R. J. van Renterghem ◽  
T. Arts ◽  
A. A. van Steenhoven ◽  
R. S. Reneman
Keyword(s):  
Magnetic Field ◽  
Aortic Valve ◽  
Cardiac Cycle ◽  
Electronic Device ◽  
Left Ventricular ◽  
Segment Length ◽  
Line Measurement ◽  
On Line ◽  
The Magnetic Field

An electronic device is described for the measurement of relative changes in segment length within the aortic valve ring during the cardiac cycle. The technique is based on the principle of magnetic induction. A magnetic field generated in one coil induces a voltage in another coil. From the amplitude of this voltage the strain between both coils can be determined because the strength of the magnetic field decreases with distance. In vitro, over a range of 5-25 mm, strains less than or equal to 0.20 strain units can be measured with an accuracy of 0.008 strain units. The frequency response is 0-150 Hz (-3 dB). By varying the generator and receiver assignment at a frequency of 2 kHz and multiplexing the signals of six coils, six strains can be measured simultaneously. As an example, simultaneous recordings of commissure strains in the aortic valve and left ventricular and ascending aortic pressures, as obtained in open-chest dogs, are shown.

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