scholarly journals Continuous Size-Dependent Sorting of Ferromagnetic Nanoparticles in Laser-Ablated Microchannel

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Yiqiang Fan ◽  
Feng Gao ◽  
Huawei Li ◽  
Gang Tang ◽  
Jian Zhuang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticles ◽  
Size Distribution ◽  
Rna Virus ◽  
Flow Direction ◽  
Low Cost ◽  
Size Dependent ◽  
Potential Applications ◽  
Size Sorting ◽  
Biological Entities

This paper reports a low-cost method of continuous size-dependent sorting of magnetic nanoparticles in polymer-based microfluidic devices by magnetic force. A neodymium permanent magnet was used to generate a magnetic field perpendicular to the fluid flow direction. Firstly, FeNi3 magnetic nanoparticles were chemically synthesized with diameter ranges from 80 nm to 200 nm; then, the solution of magnetic nanoparticles and a buffer were passed through the microchannel in laminar flow; the magnetic nanoparticles were deflected from the flow direction under the applied magnetic field. Nanoparticles in the microchannel will move towards the direction of high-gradient magnetic fields, and the degree of deflection depends on their sizes; therefore, magnetic nanoparticles of different sizes can be separated and finally collected from different output ports. The proposed method offers a rapid and continuous approach of preparing magnetic nanoparticles with a narrow size distribution from an arbitrary particle size distribution. The proposed new method has many potential applications in bioanalysis field since magnetic nanoparticles are commonly used as solid support for biological entities such as DNA, RNA, virus, and protein. Other than the size sorting application of magnetic nanoparticles, this approach could also be used for the size sorting and separation of naturally magnetic cells, including blood cells and magnetotactic bacteria.

scholarly journals Particle Size Dependent Photodynamic Anticancer Activity of Hematoporphyrin-Conjugated Fe3O4Particles

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Ki Chang Nam ◽  
Kyong-Hoon Choi ◽  
Kyu-Dong Lee ◽  
Jung Hyun Kim ◽  
Jin-Seung Jung ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Nanoparticles ◽  
Anticancer Activity ◽  
Size Dependent ◽  
Anticancer Effects ◽  
Anticancer Treatment ◽  
Wet Chemical ◽  
Biological Entities ◽  
Technical Solutions ◽  
Better Than

Nanomedicine, which involves the use of magnetic nanoparticles such as Fe3O4, has provided novel technical solutions for cancer diagnosis and treatment. Most studies in nanomedicine have focused on the use of nanoparticles with magnetic resonance imaging and hyperthermia. However, to achieve optimum anticancer effects, it is important to understand the physicochemical properties of magnetic nanoparticles and their interactions with biological entities. In this study, we synthesized Fe3O4particles of various sizes and conjugated them with hematoporphyrin (HP) molecules by using a simple surface-modification method. HP molecules were covalently bound to the surface of Fe3O4particles by a wet chemical process, resulting in Fe3O4@HPs particles that were uniform in size, were nontoxic, and exhibited strong anticancer effects on human prostate cancer (PC-3) and breast cancer (MDA-MB-231) cell lines. The Fe3O4@HPs particles showed remarkable and efficient photodynamic anticancer activity, depending on their particle size. These results indicate that all size of Fe3O4@HPs particles can be useful for photodynamic anticancer therapy, although the smaller size is better than the larger size and further studies will be needed to confirm the potential for clinical anticancer treatment.

Fe3O4nanoparticles prepared by the seeded-growth route for hyperthermia: electron magnetic resonance as a key tool to evaluate size distribution in magnetic nanoparticles

Nanoscale ◽  
2014 ◽  
Vol 6 (13) ◽  
pp. 7542-7552 ◽  
Author(s):  
Idoia Castellanos-Rubio ◽  
Maite Insausti ◽  
Eneko Garaio ◽  
Izaskun Gil de Muro ◽  
Fernando Plazaola ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Magnetic Resonance ◽  
Size Distribution ◽  
Electron Magnetic Resonance ◽  
Seeded Growth ◽  
High Quality ◽  
Power Absorption ◽  
Size Dependent ◽  
Emr Spectroscopy

High quality seeded grown Fe3O4nanoparticles show strong size dependent magnetic power absorption that can be predicted by EMR spectroscopy.

scholarly journals A Proposed Method for Thermal Specific Bioimaging and Therapy Technique for Diagnosis and Treatment of Malignant Tumors by Using Magnetic Nanoparticles

2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
Iddo M. Gescheit ◽  
Moshe Ben-David ◽  
Israel Gannot
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticles ◽  
Diagnostic Tool ◽  
Thermal Conduction ◽  
Malignant Tumors ◽  
Low Cost ◽  
Surrounding Tissue ◽  
Thermal Camera ◽  
Irreversible Damage ◽  
Therapy Technique

The objective of this research program is to develop a novel, noninvasive, low-cost infrared (8–12 μm spectral range) imaging technique that would improve upon current methods using nanostructured core/shell magnetic/noble metal-based imaging and therapies. The biocompatible magnetic nanoparticles are able to produce heat under AC magnetic field. This thermal radiation propagates along the tissue by thermal conduction reaching the medium's (tissue's) surface. The surface temperature distribution is acquired by a thermal camera and can be analyzed to retrieve and reconstruct nanoparticles' temperature and location within the tissue. The technique may function as a diagnostic tool thanks to the ability of specific bioconjugation of these nanoparticles to tumor's outer surface markers. Hence, by applying a magnetic field, we could cause a selective elevation of temperature of the targeted nanoparticles up to 5∘C, which detects the tumor. Furthermore, elevating the temperature over 65∘C and up to 100∘C stimulates a thermo ablating interaction which causes a localized irreversible damage to the cancerous site with no harm to the surrounding tissue. While functioning as a diagnostic tool, this procedure may serve as a targeted therapeutic tool under thermal feedback control as well.

scholarly journals Experimental Study on the Drag Reduction Performance of Clear Fracturing Fluid Using Wormlike Surfactant Micelles and Magnetic Nanoparticles under a Magnetic Field

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 885
Author(s):  
Ming-Liang Luo ◽  
Xiao-Dong Si ◽  
Ming-Zhong Li ◽  
Xiao-Han Jia ◽  
Yu-Ling Yang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticles ◽  
Drag Reduction ◽  
Particle System ◽  
Flow Direction ◽  
Reduction Rate ◽  
Wormlike Micelles ◽  
Fracturing Fluid ◽  
Fracturing Fluids ◽  
Viscoelastic Surfactant

This paper examines a new study on the synergistic effect of magnetic nanoparticles and wormlike micelles (WLMs) on drag reduction. Fe3O4 magnetic nanoparticles (FE-NPs) are utilized to improve the performance of viscoelastic surfactant (VES) solutions used as fracturing fluids. The chemical composition and micromorphology of the FE-NPs were analyzed with FT-IR and an electron microscope. The stability and interaction of the WLM-particle system were studied by zeta potential and cryo-TEM measurements. More importantly, the influences of the temperature, FE-NP concentration, magnetic field intensity, and direction on the drag reduction rate of WLMs were systematically investigated in a circuit pipe flow system with an electromagnetic unit. The experimental results show that a suitable content of magnetic nanoparticles can enhance the settlement stability and temperature resistance of WLMs. A magnetic field along the flow direction of the fracturing fluid can improve the drag reduction performance of the magnetic WLM system. However, under a magnetic field perpendicular to the direction of fluid flow, an additional flow resistance is generated by the vertical chaining behavior of FE-NPs, which is unfavorable for the drag reduction performance of magnetic VES fracturing fluids. This study may shed light on the mechanism of the synergistic drag reduction effects of magnetic nanoparticles and wormlike micelles.

Size Dependent Heat Generation of Magnetic Nanoparticles Under AC Magnetic Field for Cancer Therapy

2010 ◽  
pp. 415-421 ◽  
Author(s):  
Jun Motoyama ◽  
Toshiyuki Hakata ◽  
Ryuji Kato ◽  
Noriyuki Yamashita ◽  
Tomio Morino ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticles ◽  
Cancer Therapy ◽  
Heat Generation ◽  
Ac Magnetic Field ◽  
Size Dependent

A Cross-Method Comparison of Sub-10 nm Nanoparticle Size Distribution

2019 ◽  
Author(s):  
Ye Yang ◽  
Suiyang Liao ◽  
Zhi Luo ◽  
Runzhang Qi ◽  
Niamh Mac Fhionnlaoich ◽  
...  
Keyword(s):  
Size Distribution ◽  
Analytical Ultracentrifugation ◽  
Statistical Significance ◽  
Method Comparison ◽  
Size Determination ◽  
Size Dependent ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Gold Nps ◽  
Reliable Representation

Accurate nanoparticle (NP) size determination is essential across research domains, with many functions in nanoscience and biomedical research being size-dependent. Although transmission electron microscopy (TEM) is capable of resolving a single NP down to the sub-nm scale, the reliable representation of entire populations is plagued by challenges in providing statistical significance, predominantly due to limited sample counts, suboptimal preparation procedures and operator bias during image acquisition and analysis. Meanwhile alternative techniques exist, but reliable implementation requires a detailed understanding of appendant limitations. Herein, conventional TEM is compared to the size determination of sub-10 nm gold NPs in solution by small-angle X-ray scattering and analytical ultracentrifugation. Form-free Monte Carlo fitting of scattering profiles offers access to a direct representation of the core size distribution while ultracentrifugation sedimentation velocity analysis provides information of the hydrodynamic size distribution. We report a comparison of these three methods in determining the size of quasi-monodisperse, polydisperse and bimodal gold nanoparticles of 2 – 7 nm and discuss advantages and limitations of each technique.

scholarly journals Structure Unveils Relationships between RNA Virus Polymerases

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 313
Author(s):  
Heli A. M. Mönttinen ◽  
Janne J. Ravantti ◽  
Minna M. Poranen
Keyword(s):  
Phylogenetic Tree ◽  
Rna Viruses ◽  
Rna Virus ◽  
Sequence Similarity ◽  
Protein Structures ◽  
Structural Similarity ◽  
Functional Differentiation ◽  
Comparison Method ◽  
Homologous Structure ◽  
Biological Entities

RNA viruses are the fastest evolving known biological entities. Consequently, the sequence similarity between homologous viral proteins disappears quickly, limiting the usability of traditional sequence-based phylogenetic methods in the reconstruction of relationships and evolutionary history among RNA viruses. Protein structures, however, typically evolve more slowly than sequences, and structural similarity can still be evident, when no sequence similarity can be detected. Here, we used an automated structural comparison method, homologous structure finder, for comprehensive comparisons of viral RNA-dependent RNA polymerases (RdRps). We identified a common structural core of 231 residues for all the structurally characterized viral RdRps, covering segmented and non-segmented negative-sense, positive-sense, and double-stranded RNA viruses infecting both prokaryotic and eukaryotic hosts. The grouping and branching of the viral RdRps in the structure-based phylogenetic tree follow their functional differentiation. The RdRps using protein primer, RNA primer, or self-priming mechanisms have evolved independently of each other, and the RdRps cluster into two large branches based on the used transcription mechanism. The structure-based distance tree presented here follows the recently established RdRp-based RNA virus classification at genus, subfamily, family, order, class and subphylum ranks. However, the topology of our phylogenetic tree suggests an alternative phylum level organization.

scholarly journals Generation of Reverse Meniscus Flow by Applying An Electromagnetic Brake

2021 ◽  
Author(s):  
Alexander Vakhrushev ◽  
Abdellah Kharicha ◽  
Ebrahim Karimi-Sibaki ◽  
Menghuai Wu ◽  
Andreas Ludwig ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Lorentz Force ◽  
Applied Magnetic Field ◽  
Numerical Study ◽  
Flow Direction ◽  
Experimental Studies ◽  
Submerged Entry Nozzle ◽  
Mean Flow ◽  
Slab Caster ◽  
The Mean

AbstractA numerical study is presented that deals with the flow in the mold of a continuous slab caster under the influence of a DC magnetic field (electromagnetic brakes (EMBrs)). The arrangement and geometry investigated here is based on a series of previous experimental studies carried out at the mini-LIMMCAST facility at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The magnetic field models a ruler-type EMBr and is installed in the region of the ports of the submerged entry nozzle (SEN). The current article considers magnet field strengths up to 441 mT, corresponding to a Hartmann number of about 600, and takes the electrical conductivity of the solidified shell into account. The numerical model of the turbulent flow under the applied magnetic field is implemented using the open-source CFD package OpenFOAM®. Our numerical results reveal that a growing magnitude of the applied magnetic field may cause a reversal of the flow direction at the meniscus surface, which is related the formation of a “multiroll” flow pattern in the mold. This phenomenon can be explained as a classical magnetohydrodynamics (MHD) effect: (1) the closure of the induced electric current results not primarily in a braking Lorentz force inside the jet but in an acceleration in regions of previously weak velocities, which initiates the formation of an opposite vortex (OV) close to the mean jet; (2) this vortex develops in size at the expense of the main vortex until it reaches the meniscus surface, where it becomes clearly visible. We also show that an acceleration of the meniscus flow must be expected when the applied magnetic field is smaller than a critical value. This acceleration is due to the transfer of kinetic energy from smaller turbulent structures into the mean flow. A further increase in the EMBr intensity leads to the expected damping of the mean flow and, consequently, to a reduction in the size of the upper roll. These investigations show that the Lorentz force cannot be reduced to a simple damping effect; depending on the field strength, its action is found to be topologically complex.

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