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Sample records for 300i magnetic cell

  1. Magnetic needles and superparamagnetic cells

    Superparamagnetic nanoparticles can be attached in great numbers to pathogenic cells using specific antibodies so that the magnetically-labeled cells themselves become superparamagnets. The cells can then be manipulated and drawn out of biological fluids, as in a biopsy, very selectively using a magnetic needle. We examine the origins and uncertainties in the forces exerted on magnetic nanoparticles by static magnetic fields, leading to a model for trajectories and collection times of dilute superparamagnetic cells in biological fluids. We discuss the design and application of such magnetic needles and the theory of collection times. We compare the mathematical model to measurements in a variety of media including blood

  2. Magnetic levitation of single cells

    Durmus, Naside Gozde; Tekin, H. Cumhur; Guven, Sinan; Sridhar, Kaushik; Arslan Yildiz, Ahu; Calibasi, Gizem; Ghiran, Ionita; Davis, Ronald W; Steinmetz, Lars M; Demirci, Utkan

    2015-01-01

    Cells consist of micro- and nanoscale components and materials that contribute to their fundamental magnetic and density signatures. Previous studies have claimed that magnetic levitation can only be used to measure density signatures of nonliving materials. Here, we demonstrate that both eukaryotic and prokaryotic cells can be levitated and that each cell has a unique levitation profile. Furthermore, our levitation platform uniquely enables ultrasensitive density measurements, imaging, and p...

  3. First cell magnet system tests

    The ISABELLE refrigeration system utilizes compressed liquid helium to supply refrigeration to nearly 1100 superconducting bending and focusing magnets. These magnets steer the proton orbits of the accelerator and are arranged into two interlocking rings. The total heat load that the refrigerator must provide is made up of the heat load of the magnets, magnet leads and vessels and the interconnecting piping to the refrigerator. The design and test results of the magnet system during various operating conditions in use on the ISABELLE prototype, the First Cell, are described

  4. Rapid Characterization of Magnetic Moment of Cells for Magnetic Separation

    Ooi, Chinchun; Earhart, Christopher M.; Wilson, Robert J.; Wang, Shan X.

    2013-01-01

    NCI-H1650 lung cancer cell lines labeled with magnetic nanoparticles via the Epithelial Cell Adhesion Molecule (EpCAM) antigen were previously shown to be captured at high efficiencies by a microfabricated magnetic sifter. If fine control and optimization of the magnetic separation process is to be achieved, it is vital to be able to characterize the labeled cells’ magnetic moment rapidly. We have thus adapted a rapid prototyping method to obtain the saturation magnetic moment of these cells....

  5. Magnetic levitation of single cells.

    Durmus, Naside Gozde; Tekin, H Cumhur; Guven, Sinan; Sridhar, Kaushik; Arslan Yildiz, Ahu; Calibasi, Gizem; Ghiran, Ionita; Davis, Ronald W; Steinmetz, Lars M; Demirci, Utkan

    2015-07-14

    Several cellular events cause permanent or transient changes in inherent magnetic and density properties of cells. Characterizing these changes in cell populations is crucial to understand cellular heterogeneity in cancer, immune response, infectious diseases, drug resistance, and evolution. Although magnetic levitation has previously been used for macroscale objects, its use in life sciences has been hindered by the inability to levitate microscale objects and by the toxicity of metal salts previously applied for levitation. Here, we use magnetic levitation principles for biological characterization and monitoring of cells and cellular events. We demonstrate that each cell type (i.e., cancer, blood, bacteria, and yeast) has a characteristic levitation profile, which we distinguish at an unprecedented resolution of 1 × 10(-4) g ⋅ mL(-1). We have identified unique differences in levitation and density blueprints between breast, esophageal, colorectal, and nonsmall cell lung cancer cell lines, as well as heterogeneity within these seemingly homogenous cell populations. Furthermore, we demonstrate that changes in cellular density and levitation profiles can be monitored in real time at single-cell resolution, allowing quantification of heterogeneous temporal responses of each cell to environmental stressors. These data establish density as a powerful biomarker for investigating living systems and their responses. Thereby, our method enables rapid, density-based imaging and profiling of single cells with intriguing applications, such as label-free identification and monitoring of heterogeneous biological changes under various physiological conditions, including antibiotic or cancer treatment in personalized medicine. PMID:26124131

  6. Magnetically modified microbial cells: A new type of magnetic adsorbents

    Ivo Safarik; Mirka Safarikova

    2007-01-01

    Microbial cells, either in free or immobilized form, can be used for the preconcentration or removal of metal ions, organic and inorganic xenobiotics or biologically active compounds. Magnetic modification of these cells enables to prepare magnetic adsorbents that can be easily manipulated in difficult-to-handle samples, such as suspensions, in the presence of external magnetic field. In this review, typical examples of magnetic modifications of microbial cells are presented, as well as their possible applications for the separation of organic xenobiotics and heavy metal ions.

  7. Measurements of magnetic anisotropy in sickle cells

    Room temperature magnetic measurements in deoxigenated sickle cells showed the existence of magnetic anisotropy, Δchi=1,29 x 10-3. This effect was supposed paramagnetic and considered to be due to the iron atoms of the hemoglobin molecules which are one over the other, forming ordered chains inside the erythrocytes. Low temperature (liquid He - 4,2K) measurements of the magnetic anisotropy of sickle cells and normal red blood cells diluted in a cryoprotector was made to confirm the paramagnetic origin of the fenomena. For that purpose it was used a superconductor magnetometer coupled to a SQUID, developed in the 'Laboratorio do Estado Solido do Departamento de Fisica da PUC-RJ'. The results obtained seem to confirm the expected paramagnetic anisotropy and, furthermore, suggest the presence of magnetic interactions among the iron atoms in the sickle cells samples. (Author)

  8. Biological cell manipulation by magnetic nanoparticles

    Gertz, Frederick; Khitun, Alexander

    2016-02-01

    We report a manipulation of biological cells (erythrocytes) by magnetite (Fe3O4) nanoparticles in the presence of a magnetic field. The experiment was accomplished on the top of a micro-electromagnet consisting of two magnetic field generating contours. An electric current flowing through the contour(s) produces a non-uniform magnetic field, which is about 1.4 mT/μm in strength at 100 mA current in the vicinity of the current-carrying wire. In responses to the magnetic field, magnetic nanoparticles move towards the systems energy minima. In turn, magnetic nanoparticles drag biological cells in the same direction. We present experimental data showing cell manipulation through the control of electric current. This technique allows us to capture and move cells located in the vicinity (10-20 microns) of the current-carrying wires. One of the most interesting results shows a periodic motion of erythrocytes between the two conducting contours, whose frequency is controlled by an electric circuit. The obtained results demonstrate the feasibility of non-destructive cell manipulation by magnetic nanoparticles with micrometer-scale precision.

  9. Uptake of magnetic nanoparticles into cells for cell tracking

    A challenge for future applications in nanotechnology is the functional integration of nano-sized materials into cellular structures. Here we investigated superparamagnetic Fe3O4 iron oxide nanoparticles coated with a lipid bilayer for uptake into cells and for targeting subcellular compartments. It was found that magnetic nanoparticles (MNPs) are effectively taken up into cells and make cells acquire magnetic activity. Biotin-conjugated MNPs were further functionalized by binding of the fluorescent tag streptavidin-fluorescein isothiocyanate (FITC) and, following uptake into cells, shown to confer magnetic activity and fluorescence labeling. Such FITC-MNPs were localized in the lysosomal compartment of cells which suggests a receptor-mediated uptake mechanism

  10. Miniature uniaxial pressure cells for magnetic measurements

    Kamarád, Jiří; Mihalik, M.; Sechovský, V.; Arnold, Zdeněk

    2008-01-01

    Roč. 28, č. 4 (2008), s. 633-636. ISSN 0895-7959 R&D Projects: GA ČR GA202/06/0178 Institutional research plan: CEZ:AV0Z10100521 Keywords : uniaxial compression * anisotropy * CuBe pressure cell Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.852, year: 2008

  11. Multistage Magnetic Separator of Cells and Proteins

    Barton, Ken; Ainsworth, Mark; Daily, Bruce; Dunn, Scott; Metz, Bill; Vellinger, John; Taylor, Brock; Meador, Bruce

    2005-01-01

    The multistage electromagnetic separator for purifying cells and magnetic particles (MAGSEP) is a laboratory apparatus for separating and/or purifying particles (especially biological cells) on the basis of their magnetic susceptibility and magnetophoretic mobility. Whereas a typical prior apparatus based on similar principles offers only a single stage of separation, the MAGSEP, as its full name indicates, offers multiple stages of separation; this makes it possible to refine a sample population of particles to a higher level of purity or to categorize multiple portions of the sample on the basis of magnetic susceptibility and/or magnetophoretic mobility. The MAGSEP includes a processing unit and an electronic unit coupled to a personal computer. The processing unit includes upper and lower plates, a plate-rotation system, an electromagnet, an electromagnet-translation system, and a capture-magnet assembly. The plates are bolted together through a roller bearing that allows the plates to rotate with respect to each other. An interface between the plates acts as a seal for separating fluids. A lower cuvette can be aligned with as many as 15 upper cuvette stations for fraction collection during processing. A two-phase stepping motor drives the rotation system, causing the upper plate to rotate for the collection of each fraction of the sample material. The electromagnet generates a magnetic field across the lower cuvette, while the translation system translates the electromagnet upward along the lower cuvette. The current supplied to the electromagnet, and thus the magnetic flux density at the pole face of the electromagnet, can be set at a programmed value between 0 and 1,400 gauss (0.14 T). The rate of translation can be programmed between 5 and 2,000 m/s so as to align all sample particles in the same position in the cuvette. The capture magnet can be a permanent magnet. It is mounted on an arm connected to a stepping motor. The stepping motor rotates the arm to

  12. Life on magnets: stem cell networking on micro-magnet arrays.

    Zablotskii, Vitalii; Dejneka, Alexandr; Kubinová, Šárka; Le-Roy, Damien; Dumas-Bouchiat, Frédéric; Givord, Dominique; Dempsey, Nora M; Syková, Eva

    2013-01-01

    Interactions between a micro-magnet array and living cells may guide the establishment of cell networks due to the cellular response to a magnetic field. To manipulate mesenchymal stem cells free of magnetic nanoparticles by a high magnetic field gradient, we used high quality micro-patterned NdFeB films around which the stray field's value and direction drastically change across the cell body. Such micro-magnet arrays coated with parylene produce high magnetic field gradients that affect the cells in two main ways: i) causing cell migration and adherence to a covered magnetic surface and ii) elongating the cells in the directions parallel to the edges of the micro-magnet. To explain these effects, three putative mechanisms that incorporate both physical and biological factors influencing the cells are suggested. It is shown that the static high magnetic field gradient generated by the micro-magnet arrays are capable of assisting cell migration to those areas with the strongest magnetic field gradient, thereby allowing the build up of tunable interconnected stem cell networks, which is an elegant route for tissue engineering and regenerative medicine. PMID:23936425

  13. Magnetically assisted delivery of cells using a magnetic resonance imaging system

    Riegler, J [Centre for Advanced Biomedical Imaging (CABI), Department of Medicine and Institute of Child Health, University College London (UCL), London WC1E 6DD (United Kingdom); Allain, B [Centre for Medical Image Computing (CMIC) UCL, London WC1E 6BT (United Kingdom); Cook, R J [KCL Dental Institute, Biomaterials, Biomimetics and Biophotonics Group, C/O Floor 17 Tower Wing, Guy' s Hospital Campus, Great Maze Pond, London SE1 9RT (United Kingdom); Lythgoe, M F [Centre for Mathematics and Physics in the Life Sciences and Experimental Biology (CoMPLEX), UCL, London WC1E 6BT (United Kingdom); Pankhurst, Q A, E-mail: j.riegler@ucl.ac.uk [Davy-Faraday Research Laboratory, The Royal Institution of Great Britain, 21 Albemarle Street, London W1S 4BS (United Kingdom)

    2011-02-09

    A simple analytical model is presented which enables rapid interactive prediction and control of magnetically labelled cells in an arterial bifurcation using magnetic field gradients produced by a magnetic resonance imaging (MRI) system. This model is compared against experimental results for human mononuclear cells labelled with micrometre sized superparamagnetic iron oxide particles. Experimental and theoretical results highlight the importance of cell aggregation for magnetic targeting in a strong magnetic field. These predicted aggregates are confirmed via confocal endoscopy which allows the visualization of cell aggregates and their movement inside a vascular flow model in a 9.4 T preclinical MRI scanner.

  14. Magnetically assisted delivery of cells using a magnetic resonance imaging system

    A simple analytical model is presented which enables rapid interactive prediction and control of magnetically labelled cells in an arterial bifurcation using magnetic field gradients produced by a magnetic resonance imaging (MRI) system. This model is compared against experimental results for human mononuclear cells labelled with micrometre sized superparamagnetic iron oxide particles. Experimental and theoretical results highlight the importance of cell aggregation for magnetic targeting in a strong magnetic field. These predicted aggregates are confirmed via confocal endoscopy which allows the visualization of cell aggregates and their movement inside a vascular flow model in a 9.4 T preclinical MRI scanner.

  15. Magnetic characterization of isolated candidate vertebrate magnetoreceptor cells.

    Eder, Stephan H K; Cadiou, Hervé; Muhamad, Airina; McNaughton, Peter A; Kirschvink, Joseph L; Winklhofer, Michael

    2012-07-24

    Over the past 50 y, behavioral experiments have produced a large body of evidence for the existence of a magnetic sense in a wide range of animals. However, the underlying sensory physiology remains poorly understood due to the elusiveness of the magnetosensory structures. Here we present an effective method for isolating and characterizing potential magnetite-based magnetoreceptor cells. In essence, a rotating magnetic field is employed to visually identify, within a dissociated tissue preparation, cells that contain magnetic material by their rotational behavior. As a tissue of choice, we selected trout olfactory epithelium that has been previously suggested to host candidate magnetoreceptor cells. We were able to reproducibly detect magnetic cells and to determine their magnetic dipole moment. The obtained values (4 to 100 fAm(2)) greatly exceed previous estimates (0.5 fAm(2)). The magnetism of the cells is due to a μm-sized intracellular structure of iron-rich crystals, most likely single-domain magnetite. In confocal reflectance imaging, these produce bright reflective spots close to the cell membrane. The magnetic inclusions are found to be firmly coupled to the cell membrane, enabling a direct transduction of mechanical stress produced by magnetic torque acting on the cellular dipole in situ. Our results show that the magnetically identified cells clearly meet the physical requirements for a magnetoreceptor capable of rapidly detecting small changes in the external magnetic field. This would also explain interference of ac powerline magnetic fields with magnetoreception, as reported in cattle. PMID:22778440

  16. Rare Cell Separation and Analysis by Magnetic Sorting

    Zborowski, Maciej; Chalmers, Jeffrey J.

    2011-01-01

    The separation and or isolation of rare cells using magnetic forces is commonly used and growing in use ranging from simple sample prep for further studies to a FDA approved, clinical diagnostic test. This grown is the result of both the demand to obtain homogeneous rare cells for molecular analysis and the dramatic increases in the power of permanent magnets that even allow the separation of some unlabeled cells based on intrinsic magnetic moments, such as malaria parasite-infected red blood...

  17. Magnetic nanoparticles as bimodal tools in magnetically induced labelling and magnetic heating of tumour cells: an in vitro study

    Kettering, M.; Winter, J.; Zeisberger, M.; Bremer-Streck, S.; Oehring, H.; Bergemann, C.; Alexiou, C.; Hergt, R.; Halbhuber, K. J.; Kaiser, W. A.; Hilger, I.

    2007-05-01

    Localized magnetic heating treatments (hyperthermia, thermal ablation) using superparamagnetic iron oxide nanoparticles continue to be an active area of cancer research. The present study uses magnetic nanoparticles (MNP) as bimodal tools and combines magnetically induced cell labelling and magnetic heating. The main focus was to assess if a selective and higher MNP accumulation within tumour cells due to magnetic labelling (max. 56 and 83 mT) and consequently a larger heating effect occurs after exposure to an alternating magnetic field (magnetic heating: frequency 400 kHz, amplitude 24.6 kA m-1) in order to eliminate labelled tumour cells effectively. The results demonstrate that the magnetically based cellular MNP uptake by human adenocarcinoma cells is due to suitable magnetic field gradients in vitro which intensify the temperature increase generated during magnetic heating. A significantly (P<=0.05) enhanced MNP cell uptake due to 83 mT labelling compared to controls or to 56 mT labelling was observed. Our experiments required the following conditions, namely a cell concentration of 2.5 × 107 cells ml-1, a minimum MNP concentration of 0.32 mg Fe ml-1 culture medium, and an incubation time of 24 h, to reach this effect as well as for the significantly enlarged heating effects to occur.

  18. The effect of an external magnetic force on cell adhesion and proliferation of magnetically labeled mesenchymal stem cells

    Nakamae Toshio

    2010-02-01

    Full Text Available Abstract Background As the strategy for tissue regeneration using mesenchymal stem cells (MSCs for transplantation, it is necessary that MSCs be accumulated and kept in the target area. To accumulate MSCs effectively, we developed a novel technique for a magnetic targeting system with magnetically labeled MSCs and an external magnetic force. In this study, we examined the effect of an external magnetic force on magnetically labeled MSCs in terms of cell adhesion and proliferation. Methods Magnetically labeled MSCs were plated at the bottom of an insert under the influence of an external magnetic force for 1 hour. Then the inserts were turned upside down for between 1 and 24 hours, and the number of MSCs which had fallen from the membrane was counted. The gene expression of MSCs affected magnetic force was analyzed with microarray. In the control group, the same procedure was done without the external magnetic force. Results At 1 hour after the inserts were turned upside down, the average number of fallen MSCs in the magnetic group was significantly smaller than that in the control group, indicating enhanced cell adhesion. At 24 hours, the average number of fallen MSCs in the magnetic group was also significantly smaller than that in control group. In the magnetic group, integrin alpha2, alpha6, beta3 BP, intercellular adhesion molecule-2 (ICAM-2, platelet/endothelial cell adhesion molecule-1 (PECAM-1 were upregulated. At 1, 2 and 3 weeks after incubation, there was no statistical significant difference in the numbers of MSCs in the magnetic group and control group. Conclusions The results indicate that an external magnetic force for 1 hour enhances cell adhesion of MSCs. Moreover, there is no difference in cell proliferation after using an external magnetic force on magnetically labeled MSCs.

  19. Modeling the efficiency of a magnetic needle for collecting magnetic cells.

    Butler, Kimberly S; Adolphi, Natalie L; Bryant, H C; Lovato, Debbie M; Larson, Richard S; Flynn, Edward R

    2014-07-01

    As new magnetic nanoparticle-based technologies are developed and new target cells are identified, there is a critical need to understand the features important for magnetic isolation of specific cells in fluids, an increasingly important tool in disease research and diagnosis. To investigate magnetic cell collection, cell-sized spherical microparticles, coated with superparamagnetic nanoparticles, were suspended in (1) glycerine-water solutions, chosen to approximate the range of viscosities of bone marrow, and (2) water in which 3, 5, 10 and 100% of the total suspended microspheres are coated with magnetic nanoparticles, to model collection of rare magnetic nanoparticle-coated cells from a mixture of cells in a fluid. The magnetic microspheres were collected on a magnetic needle, and we demonstrate that the collection efficiency versus time can be modeled using a simple, heuristically-derived function, with three physically-significant parameters. The function enables experimentally-obtained collection efficiencies to be scaled to extract the effective drag of the suspending medium. The results of this analysis demonstrate that the effective drag scales linearly with fluid viscosity, as expected. Surprisingly, increasing the number of non-magnetic microspheres in the suspending fluid results increases the collection of magnetic microspheres, corresponding to a decrease in the effective drag of the medium. PMID:24874577

  20. Micro-magnet arrays for specific single bacterial cell positioning

    Pivetal, Jérémy, E-mail: jeremy.piv@netcmail.com [Ecole Centrale de Lyon, CNRS UMR 5005, Laboratoire Ampère, F-69134 Écully (France); Royet, David [Ecole Centrale de Lyon, CNRS UMR 5005, Laboratoire Ampère, F-69134 Écully (France); Ciuta, Georgeta [Univ. Grenoble Alpes, Inst NEEL, F-38042 Grenoble (France); CNRS, Inst NEEL, F-38042 Grenoble (France); Frenea-Robin, Marie [Université de Lyon, Université Lyon 1, CNRS UMR 5005, Laboratoire Ampère, F-69622 Villeurbanne (France); Haddour, Naoufel [Ecole Centrale de Lyon, CNRS UMR 5005, Laboratoire Ampère, F-69134 Écully (France); Dempsey, Nora M. [Univ. Grenoble Alpes, Inst NEEL, F-38042 Grenoble (France); CNRS, Inst NEEL, F-38042 Grenoble (France); Dumas-Bouchiat, Frédéric [Univ Limoges, CNRS, SPCTS UMR 7513, 12 Rue Atlantis, F-87068 Limoges (France); Simonet, Pascal [Ecole Centrale de Lyon, CNRS UMR 5005, Laboratoire Ampère, F-69134 Écully (France)

    2015-04-15

    In various contexts such as pathogen detection or analysis of microbial diversity where cellular heterogeneity must be taken into account, there is a growing need for tools and methods that enable microbiologists to analyze bacterial cells individually. One of the main challenges in the development of new platforms for single cell studies is to perform precise cell positioning, but the ability to specifically target cells is also important in many applications. In this work, we report the development of new strategies to selectively trap single bacterial cells upon large arrays, based on the use of micro-magnets. Escherichia coli bacteria were used to demonstrate magnetically driven bacterial cell organization. In order to provide a flexible approach adaptable to several applications in the field of microbiology, cells were magnetically and specifically labeled using two different strategies, namely immunomagnetic labeling and magnetic in situ hybridization. Results show that centimeter-sized arrays of targeted, isolated bacteria can be successfully created upon the surface of a flat magnetically patterned hard magnetic film. Efforts are now being directed towards the integration of a detection tool to provide a complete micro-system device for a variety of microbiological applications. - Highlights: 1.We report a new approach to selectively micropattern bacterial cells individually upon micro-magnet arrays. 2.Permanent micro-magnets of a size approaching that of bacteria could be fabricated using a Thermo-Magnetic Patterning process. 3.Bacterial cells were labeled using two different magnetic labeling strategies providing flexible approach adaptable to several applications in the field of microbiology.

  1. Micro-magnet arrays for specific single bacterial cell positioning

    In various contexts such as pathogen detection or analysis of microbial diversity where cellular heterogeneity must be taken into account, there is a growing need for tools and methods that enable microbiologists to analyze bacterial cells individually. One of the main challenges in the development of new platforms for single cell studies is to perform precise cell positioning, but the ability to specifically target cells is also important in many applications. In this work, we report the development of new strategies to selectively trap single bacterial cells upon large arrays, based on the use of micro-magnets. Escherichia coli bacteria were used to demonstrate magnetically driven bacterial cell organization. In order to provide a flexible approach adaptable to several applications in the field of microbiology, cells were magnetically and specifically labeled using two different strategies, namely immunomagnetic labeling and magnetic in situ hybridization. Results show that centimeter-sized arrays of targeted, isolated bacteria can be successfully created upon the surface of a flat magnetically patterned hard magnetic film. Efforts are now being directed towards the integration of a detection tool to provide a complete micro-system device for a variety of microbiological applications. - Highlights: 1.We report a new approach to selectively micropattern bacterial cells individually upon micro-magnet arrays. 2.Permanent micro-magnets of a size approaching that of bacteria could be fabricated using a Thermo-Magnetic Patterning process. 3.Bacterial cells were labeled using two different magnetic labeling strategies providing flexible approach adaptable to several applications in the field of microbiology

  2. Quantitative Magnetic Separation of Particles and Cells Using Gradient Magnetic Ratcheting.

    Murray, Coleman; Pao, Edward; Tseng, Peter; Aftab, Shayan; Kulkarni, Rajan; Rettig, Matthew; Di Carlo, Dino

    2016-04-13

    Extraction of rare target cells from biosamples is enabling for life science research. Traditional rare cell separation techniques, such as magnetic activated cell sorting, are robust but perform coarse, qualitative separations based on surface antigen expression. A quantitative magnetic separation technology is reported using high-force magnetic ratcheting over arrays of magnetically soft micropillars with gradient spacing, and the system is used to separate and concentrate magnetic beads based on iron oxide content (IOC) and cells based on surface expression. The system consists of a microchip of permalloy micropillar arrays with increasing lateral pitch and a mechatronic device to generate a cycling magnetic field. Particles with higher IOC separate and equilibrate along the miropillar array at larger pitches. A semi-analytical model is developed that predicts behavior for particles and cells. Using the system, LNCaP cells are separated based on the bound quantity of 1 μm anti-epithelial cell adhesion molecule (EpCAM) particles as a metric for expression. The ratcheting cytometry system is able to resolve a ±13 bound particle differential, successfully distinguishing LNCaP from PC3 populations based on EpCAM expression, correlating with flow cytometry analysis. As a proof-of-concept, EpCAM-labeled cells from patient blood are isolated with 74% purity, demonstrating potential toward a quantitative magnetic separation instrument. PMID:26890496

  3. On-chip cell sorting via patterned magnetic traps

    Byvank, Tom; Prikockis, Michael; Chen, Aaron; Miller, Brandon; Chalmers, Jeffrey; Sooryakumar, Ratnasingham

    2015-03-01

    Due to their importance in research for the diagnosis and treatment of cancer, numerous schemes have been developed to sort rare cell populations, e.g., circulating tumor cells (CTCs), from a larger ensemble of cells. Here, we improve upon a previously developed microfluidic device (Lab Chip 13, 1172, (2013)) to increase throughput and sorting purity of magnetically labeled cells. The separation mechanism involves controlling magnetic forces by manipulating the magnetic domain structures of embedded permalloy microdisks with weak external fields. These forces move labeled cells from the input flow stream into an adjacent buffer flow stream. Such magnetically activated transfer separates the magnetic entities from their non-magnetic counterparts as the two flow streams split apart and move toward their respective outputs. Purity of the magnetic output is modulated by the withdrawal rate of the non-magnetic output relative to the inputs. A proof of concept shows that CTCs from metastatic breast cancer patients can be sorted, recovered from the device, and confirmed as CTCs using separate immunofluorescence staining and analysis. With further optimizations, the channel could become a useful device for high purity final sorting of enriched patient cell samples.

  4. Copper Biosorption on Magnetically Modified Yeast Cells Under Magnetic Field

    Uzun, L.; Saglam, N.; Šafaříková, Miroslava; Šafařík, Ivo; Denizli, A.

    2011-01-01

    Roč. 46, č. 6 (2011), s. 1045-1051. ISSN 0149-6395 Institutional research plan: CEZ:AV0Z60870520 Keywords : copper removal * heavy metal removal * magnetic biosorbents * yeast Subject RIV: CE - Biochemistry Impact factor: 1.088, year: 2011

  5. Magnetic Nanowires as Materials for Cancer Cell Destruction

    Contreras, Maria F.

    2015-12-01

    Current cancer therapies are highly cytotoxic and their delivery to exclusively the affected site is poorly controlled, resulting in unavoidable and often severe side effects. In an effort to overcome such issues, magnetic nanoparticles have been recently gaining relevance in the areas of biomedical applications and therapeutics, opening pathways to alternative methods. This led to the concept of magnetic particle hyperthermia in which magnetic nano beads are heated by a high power magnetic field. The increase in temperature kills the cancer cells, which are more susceptible to heat in comparison to healthy cells. In this dissertation, the possibility to kill cancer cells with magnetic nanowires is evaluated. The idea is to exploit a magnetomechanical effect, where nanowires cause cancer cell death through vibrating in a low power magnetic field. Specifically, the magnetic nanowires effects to cells in culture and their ability to induce cancer cell death, when combined with an alternating magnetic field, was investigated. Nickel and iron nanowires of 35 nm diameter and 1 to 5 μm long were synthesized by electrodeposition into nanoporous alumina templates, which were prepared using a two-step anodization process on highly pure aluminum substrates. For the cytotoxicity studies, the nanowires were added to cancer cells in culture, varying the incubation time and the concentration. The cell-nanowire interaction was thoroughly studied at the cellular level (mitochondrial metabolic activity, cell membrane integrity and, apoptosis/necrosis assay), and optical level (transmission electron and confocal microscopy). Furthermore, to investigate their therapeutic potential, an alternating magnetic field was applied varying its intensity and frequency. After the magnetic field application, cells health was measured at the mitochondrial activity level. Cytotoxicity results shed light onto the cellular tolerance to the nanowires, which helped in establishing the appropriate

  6. Effect of Magnetic Field on L-Strain Cells

    Ulakoglu, G; Atak, C; Rzakoulieva, A; Danilov, V I; Alikamanoglu, S

    2000-01-01

    The effects of electromagnetic and magnetic fields are currently being made useful in many fields, especially in medicine. In this research work, L-Strain cells which are a type of fibrosarcoma cells were exposed to a magnetic flow of 2-26 mT in periods of 1, 2, 3 and 4 minutes. The L-Strain cells, which were exposed to the magnetic field for these periods, were counted after 24 and 48 hours, when compared with the controls, it was observed that in groups of 1 and 4 minutes exposure a significant decrease (P < 0.05) in the number of cells occurred. The per cent of labelling index of L-Strain cells exposed to the magnetic field for 1 and 4 minutes decreased significantly also in comparison to the controls.

  7. Effects of Magnetic Field on Biological Cells and Applications

    Chen, Ching-Jen

    2001-03-01

    While there has been extensive research performed in the physics of magnetic fields and the physics and chemistry in life sciences, independent of each other, there has been a paucity of scientific research and development investigating the possible applications of magnetic fields in life sciences. The focus of this presentation is to present the stimulation mechanism by which magnetic fields affect (a) yeast cells (b) plant cells and (c) mammalian normal and cancer cells. Recently we have found that the Saccharomyces Cerevsa yeast growth increases by about 30to a 1 tesla field and the production of CO2 increases by about 30of yeast metabolism may be due to an increase in intercellular interaction and protein channel alignment, the introduction of an alteration in the DNA from the magnetic field exposure or a combination of these mechanisms. We also have found that the application of high magnetic fields (1 tesla and above) can have marked effects on the germination and growth of plants, especially corn, beans and peas. This finding has opened up the possibility of technology developments in botanical growth systems to accelerate seed germination and crop harvesting. Most recently we have investigated the application of high magnetic fields on leukemia, CaCoII and HEP G2 cancer cell lines. We found that when leukemia are exposed to a 12 tesla field for 2 hours has an increase in cell death by about 30that were not exposed to the magnetic field. Viability of CaCoII cells sandwiched between permanent magnets of maximum strength of 1.2 tesla was measured. A decrease in viable cells by 33unexposed cells. HSP 70 was measured for HEPG2 cells that were exposed to permanent magnetic field of 1.2 tesla for 40 minutes and for unexposed cells. It was found that the exposed cells produce 19 times more HSP70 compared to unexposed cells. Our results together with other investigators report suggest a strong evidence of a reduction in the cell growth rate for cancer cells when

  8. Targeted cancer cell death induced by biofunctionalized magnetic nanowires

    Contreras, Maria F.

    2014-02-01

    Magnetic micro and nanomaterials are increasingly interesting for biomedical applications since they possess many advantageous properties: they can become biocompatible, they can be functionalized to target specific cells and they can be remotely manipulated by magnetic fields. The goal of this study is to use antibody-functionalized nickel nanowires (Ab-NWs) as an alternative method in cancer therapy overcoming the limitations of current treatments that lack specificity and are highly cytotoxic. Ab-NWs have been incubated with cancer cells and a 12% drop on cell viability was observed for a treatment of only 10 minutes and an alternating magnetic field of low intensity and low frequency. It is believed that the Ab-NWs vibrate transmitting a mechanical force to the targeted cells inducing cell death. © 2014 IEEE.

  9. Instant magnetic labeling of tumor cells by ultrasound in vitro

    Mo, Runyang; Yang, Jian; Wu, Ed X.; Lin, Shuyu

    2011-09-01

    Magnetic labeling of living cells creates opportunities for numerous biomedical applications. Here we describe an instantly cell magnetic labeling method based on ultrasound. We present a detailed study on the ultrasound performance of a simple and efficient labeling protocol for H-22 cells in vitro. High frequency focus ultrasound was investigated as an alternative method to achieve instant cell labeling with the magnetic particles without the need for adjunct agents or initiating cell cultures. Mean diameter of 168 nm dextran-T40 coated superparamagnetic iron oxide (SPIO) nanoparticles were prepared by means of classical coprecipitation in solution in our laboratory. H-22 tumor cells suspended in phosphate-buffered saline (PBS, pH=7.2) were exposed to ultrasound at 1.37 MHz for up to 120 s in the presence of SPIOs. The cellular uptake of iron oxide nanoparticles was detected by prussion blue staining. The viability of cells was determined by a trypan blue exclusion test. At 2 W power and 60 s ultrasound exposure in presence of 410 μg/ml SPIOs, H-22 cell labeling efficiency reached 69.4±6.3% and the labeled cells exhibited an iron content of 10.38±2.43 pg per cell. Furthermore, 95.2±3.2% cells remained viable. The results indicated that the ultrasound protocol could be potentially applied to label cells with large-sized magnetic particles. We also calculated the shear stress at the 2 W power and 1.37 MHz used in experiments. The results showed that the shear stress threshold for ultrasonically induced H-22 cell reparable sonoporation was 697 Pa. These findings provide a quantitative guidance in designing ultrasound protocols for cell labeling.

  10. Magnetically Targeted Stem Cell Delivery for Regenerative Medicine

    Jhon Cores

    2015-06-01

    Full Text Available Stem cells play a special role in the body as agents of self-renewal and auto-reparation for tissues and organs. Stem cell therapies represent a promising alternative strategy to regenerate damaged tissue when natural repairing and conventional pharmacological intervention fail to do so. A fundamental impediment for the evolution of stem cell therapies has been the difficulty of effectively targeting administered stem cells to the disease foci. Biocompatible magnetically responsive nanoparticles are being utilized for the targeted delivery of stem cells in order to enhance their retention in the desired treatment site. This noninvasive treatment-localization strategy has shown promising results and has the potential to mitigate the problem of poor long-term stem cell engraftment in a number of organ systems post-delivery. In addition, these same nanoparticles can be used to track and monitor the cells in vivo, using magnetic resonance imaging. In the present review we underline the principles of magnetic targeting for stem cell delivery, with a look at the logic behind magnetic nanoparticle systems, their manufacturing and design variants, and their applications in various pathological models.

  11. Magnetization of microorganism cells by sol-gel method

    2008-01-01

    Microorganism cells could be used as templates during fabrication of magnetic or conductive microstructures in different standard shapes. In this paper, feasibility of magnetizing microorganism cells by sol-gel method, which is to coat cells of Spirulina (a type of natural micro-helical microorganism) with the ferrite (a kind of magnetic material), was discussed and investigated. Then the cell form, components and the phase structure were observed and analyzed using various tools including optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray detector (EDX), transmission electron microscopy (TEM), and X-ray diffraction analysis (XRD). Results showed that spirulina cells could be coated with ferrite after the sol-gel process, with the shape of natural helixes well kept, that the components of different sampling points on the surface layer were consistent and the thickness of layer was uniform, and that the type of the surface ferrite layer formed was cubic Fe3O4. It was also observed that there were nano-particles yielded in the cells and certain deposit on the walls between cells. The kinetics of the cell magnetization technology by sol-gel was also discussed.

  12. An efficient magnetically modified microbial cell biocomposite for carbazole biodegradation

    Li, Yufei; Du, Xiaoyu; Wu, Chao; Liu, Xueying; Wang, Xia; Xu, Ping

    2013-12-01

    Magnetic modification of microbial cells enables to prepare smart biocomposites in bioremediation. In this study, we constructed an efficient biocomposite by assembling Fe3O4 nanoparticles onto the surface of Sphingomonas sp. XLDN2-5 cells. The average particle size of Fe3O4 nanoparticles was about 20 nm with 45.5 emu g-1 saturation magnetization. The morphology of Sphingomonas sp. XLDN2-5 cells before and after Fe3O4 nanoparticle loading was verified by scanning electron microscopy and transmission electronic microscopy. Compared with free cells, the microbial cell/Fe3O4 biocomposite had the same biodegradation activity but exhibited remarkable reusability. The degradation activity of the microbial cell/Fe3O4 biocomposite increased gradually during recycling processes. Additionally, the microbial cell/Fe3O4 biocomposite could be easily separated and recycled by an external magnetic field due to the super-paramagnetic properties of Fe3O4 nanoparticle coating. These results indicated that magnetically modified microbial cells provide a promising technique for improving biocatalysts used in the biodegradation of hazardous compounds.

  13. High gradient magnetic field microstructures for magnetophoretic cell separation.

    Abdel Fattah, Abdel Rahman; Ghosh, Suvojit; Puri, Ishwar K

    2016-08-01

    Microfluidics has advanced magnetic blood fractionation by making integrated miniature devices possible. A ferromagnetic microstructure array that is integrated with a microfluidic channel rearranges an applied magnetic field to create a high gradient magnetic field (HGMF). By leveraging the differential magnetic susceptibilities of cell types contained in a host medium, such as paramagnetic red blood cells (RBCs) and diamagnetic white blood cells (WBCs), the resulting HGMF can be used to continuously separate them without attaching additional labels, such as magnetic beads, to them. We describe the effect of these ferromagnetic microstructure geometries have on the blood separation efficacy by numerically simulating the influence of microstructure height and pitch on the HGMF characteristics and resulting RBC separation. Visualizations of RBC trajectories provide insight into how arrays can be optimized to best separate these cells from a host fluid. Periodic microstructures are shown to moderate the applied field due to magnetic interference between the adjacent teeth of an array. Since continuous microstructures do not similarly weaken the resultant HGMF, they facilitate significantly higher RBC separation. Nevertheless, periodic arrays are more appropriate for relatively deep microchannels since, unlike continuous microstructures, their separation effectiveness is independent of depth. The results are relevant to the design of microfluidic devices that leverage HGMFs to fractionate blood by separating RBCs and WBCs. PMID:27294532

  14. Test chambers for cell culture in static magnetic field

    Article presents a test chamber intended to be used for in vitro cell culture in homogenous constant magnetic field with parametrically variable magnitude. We constructed test chambers with constant parameters of control homeostasis of cell culture for the different parameters of static magnetic field. The next step was the computer calculation of 2D and 3D simulation of the static magnetic field distribution in the chamber. The analysis of 2D and 3D calculations of magnetic induction in the cells' exposition plane reveals, in comparison to the detection results, the greater accuracy of 2D calculations (Figs. 9 and 10). The divergence in 2D method was 2–4% and 8 to 10% in 3D method (reaching 10% only out of the cells′ cultures margins). -- Highlights: ► We present test chamber to be used for in vitro cell culture in static magnetic field. ► The technical data of the chamber construction was presented. ► 2D versus 3D simulation of static magnetic field distribution in chamber was reported. ► We report the accuracy of 2D calculation than 3D

  15. Comparison of designed and commercial magnetic cell labels: relaxivity, cell uptake, cell viability

    Herynek, V.; Glogarová, Kateřina; Horák, Daniel; Jendelová, Pavla; Syková, Eva; Hájek, M.

    Warsawa : ESMRMB, 2006. s. 283-284. [Congress of European Society for Magnetic Resonance in Medicine and Biology /23./. 21.09.2006-23.09.2006, Warsawa] R&D Projects: GA ČR(CZ) GA309/06/1594; GA MŠk 1M0538 Institutional research plan: CEZ:AV0Z50390512 Keywords : Cell * MR Subject RIV: FH - Neurology

  16. Influence on cell death of high frequency motion of magnetic nanoparticles during magnetic hyperthermia experiments

    Hallali, N.; Clerc, P.; Fourmy, D.; Gigoux, V.; Carrey, J.

    2016-07-01

    Studies with transplanted tumors in animals and clinical trials have provided the proof-of-concept of magnetic hyperthermia (MH) therapy of cancers using iron oxide nanoparticles. Interestingly, in several studies, the application of an alternating magnetic field (AMF) to tumor cells having internalized and accumulated magnetic nanoparticles (MNPs) into their lysosomes can induce cell death without detectable temperature increase. To explain these results, among other hypotheses, it was proposed that cell death could be due to the high-frequency translational motion of MNPs under the influence of the AMF gradient generated involuntarily by most inductors. Such mechanical actions of MNPs might cause cellular damages and participate in the induction of cell death under MH conditions. To test this hypothesis, we developed a setup maximizing this effect. It is composed of an anti-Helmholtz coil and two permanent magnets, which produce an AMF gradient and a superimposed static MF. We have measured the MNP heating power and treated tumor cells by a standard AMF and by an AMF gradient, on which was added or not a static magnetic field. We showed that the presence of a static magnetic field prevents MNP heating and cell death in standard MH conditions. The heating power of MNPs in an AMF gradient is weak, position-dependent, and related to the presence of a non-zero AMF. Under an AMF gradient and a static field, no MNP heating and cell death were measured. Consequently, the hypothesis that translational motions could be involved in cell death during MH experiments is ruled out by our experiments.

  17. Hydrogen peroxide removal with magnetically responsive Saccharomyces cerevisiae cells

    Šafařík, Ivo; Maděrová, Zdeňka; Šafaříková, Miroslava

    2008-01-01

    Roč. 56, - (2008), s. 7925-7928. ISSN 0021-8561 R&D Projects: GA MPO 2A-1TP1/094; GA MŠk OC 157 Institutional research plan: CEZ:AV0Z60870520 Keywords : magnetic alginate beads * catalase * magnetic separation * Saccharomyces cerevisiae cells * hydrogen peroxide Subject RIV: GM - Food Processing Impact factor: 2.562, year: 2008

  18. Life on magnets: stem cell networking on micro-magnet arrays

    Zablotskyy, Vitaliy A.; Dejneka, Alexandr; Kubinová, Šárka; Le-Roy, D.; Dumas-Bouchiat, F.; Givord, D.; Dempsey, N.; Syková, Eva

    2013-01-01

    Roč. 8, č. 8 (2013), e70416. E-ISSN 1932-6203 R&D Projects: GA ČR GAP304/11/0653; GA ČR(CZ) GAP304/12/1370 Grant ostatní: AV ČR(CZ) M100101219 Institutional support: RVO:68378271 ; RVO:68378041 Keywords : micro-magnet * stem cells Subject RIV: BM - Solid Matter Physics ; Magnetism; FH - Neurology (UEM-P) Impact factor: 3.534, year: 2013

  19. Detection of molecules and cells using nuclear magnetic resonance with magnetic nanoparticles

    For the detection of small molecules, proteins or even cells in vitro, functionalised magnetic nanoparticles and nuclear magnetic resonance measurements can be applied. In this work, magnetic nanoparticles with the size of 5–7 nm were functionalised with antibodies to detect two model systems of different sizes, the protein avidin and Saccharomyces cerevisiae as the model organism. The synthesised magnetic nanoparticles showed a narrow size distribution, which was determined using transmission electron microscopy and dynamic light scattering. The magnetic nanoparticles were functionalised with the according antibodies via EDC/NHS chemistry. The binding of the antigen to magnetic nanoparticles was detected through the change in the NMR T2 relaxation time at 0.5 T (≈21.7 MHz). In case of a specific binding the particles cluster and the T2 relaxation time of the sample changes. The detection limit in buffer for FITC-avidin was determined to be 1.35 nM and 107 cells/ml for S. cerevisiae. For fluorescent microscopy the avidin molecules were labelled with FITC and for the detection of S. cerevisiae the magnetic nanoparticles were additionally functionalised with rhodamine. The binding of the particles to S. cerevisiae and the resulting clustering was also seen by transmission electron microscopy

  20. Detection of molecules and cells using nuclear magnetic resonance with magnetic nanoparticles

    Rümenapp, Christine, E-mail: ruemenapp@tum.de [Zentralinstitut für Medizintechnik (IMETUM), Technische Universität München, Garching (Germany); Gleich, Bernhard [Zentralinstitut für Medizintechnik (IMETUM), Technische Universität München, Garching (Germany); Mannherz, Hans Georg [Abteilung für Anatomie und Molekulare Embryologie, Ruhr Universität Bochum, Bochum (Germany); Haase, Axel [Zentralinstitut für Medizintechnik (IMETUM), Technische Universität München, Garching (Germany)

    2015-04-15

    For the detection of small molecules, proteins or even cells in vitro, functionalised magnetic nanoparticles and nuclear magnetic resonance measurements can be applied. In this work, magnetic nanoparticles with the size of 5–7 nm were functionalised with antibodies to detect two model systems of different sizes, the protein avidin and Saccharomyces cerevisiae as the model organism. The synthesised magnetic nanoparticles showed a narrow size distribution, which was determined using transmission electron microscopy and dynamic light scattering. The magnetic nanoparticles were functionalised with the according antibodies via EDC/NHS chemistry. The binding of the antigen to magnetic nanoparticles was detected through the change in the NMR T{sub 2} relaxation time at 0.5 T (≈21.7 MHz). In case of a specific binding the particles cluster and the T{sub 2} relaxation time of the sample changes. The detection limit in buffer for FITC-avidin was determined to be 1.35 nM and 10{sup 7} cells/ml for S. cerevisiae. For fluorescent microscopy the avidin molecules were labelled with FITC and for the detection of S. cerevisiae the magnetic nanoparticles were additionally functionalised with rhodamine. The binding of the particles to S. cerevisiae and the resulting clustering was also seen by transmission electron microscopy.

  1. Instant magnetic labeling of tumor cells by ultrasound in vitro

    Magnetic labeling of living cells creates opportunities for numerous biomedical applications. Here we describe an instantly cell magnetic labeling method based on ultrasound. We present a detailed study on the ultrasound performance of a simple and efficient labeling protocol for H-22 cells in vitro. High frequency focus ultrasound was investigated as an alternative method to achieve instant cell labeling with the magnetic particles without the need for adjunct agents or initiating cell cultures. Mean diameter of 168 nm dextran-T40 coated superparamagnetic iron oxide (SPIO) nanoparticles were prepared by means of classical coprecipitation in solution in our laboratory. H-22 tumor cells suspended in phosphate-buffered saline (PBS, pH=7.2) were exposed to ultrasound at 1.37 MHz for up to 120 s in the presence of SPIOs. The cellular uptake of iron oxide nanoparticles was detected by prussion blue staining. The viability of cells was determined by a trypan blue exclusion test. At 2 W power and 60 s ultrasound exposure in presence of 410 μg/ml SPIOs, H-22 cell labeling efficiency reached 69.4±6.3% and the labeled cells exhibited an iron content of 10.38±2.43 pg per cell. Furthermore, 95.2±3.2% cells remained viable. The results indicated that the ultrasound protocol could be potentially applied to label cells with large-sized magnetic particles. We also calculated the shear stress at the 2 W power and 1.37 MHz used in experiments. The results showed that the shear stress threshold for ultrasonically induced H-22 cell reparable sonoporation was 697 Pa. These findings provide a quantitative guidance in designing ultrasound protocols for cell labeling. - Highlights: → High frequency focus ultrasound can be used as a safe method for instant magnetic labeling of cells. → 8-16 times increased efficiency can be gained by ultrasound versus that by transfection agents. → Calculation of shear stress around cells provide a quantitative design for ultrasound protocols.

  2. Instant magnetic labeling of tumor cells by ultrasound in vitro

    Mo Runyang, E-mail: mmrryycn@snnu.edu.cn [Shaanxi Key Laboratory of Ultrasonic, College of Physics and Information Technology, Shaanxi Normal University, No. 199 of South Changan Road, Xi' an 710062 (China); Yang Jian, E-mail: cjr.yangjian@vip.163.com [Department of Diagnostic Radiology, The First Hospital of Medical School, Xi' an Jiaotong University, No. 277 of West Yanta Road, Shannxi Province, Xi' an 710062 (China); Wu, Ed X. [Laboratory of Biomedical Imaging and Signal Processing, University of Hong Kong, Pokfulam, Hong Kong (Hong Kong); Lin Shuyu [Shaanxi Key Laboratory of Ultrasonic, College of Physics and Information Technology, Shaanxi Normal University, No. 199 of South Changan Road, Xi' an 710062 (China)

    2011-09-15

    Magnetic labeling of living cells creates opportunities for numerous biomedical applications. Here we describe an instantly cell magnetic labeling method based on ultrasound. We present a detailed study on the ultrasound performance of a simple and efficient labeling protocol for H-22 cells in vitro. High frequency focus ultrasound was investigated as an alternative method to achieve instant cell labeling with the magnetic particles without the need for adjunct agents or initiating cell cultures. Mean diameter of 168 nm dextran-T40 coated superparamagnetic iron oxide (SPIO) nanoparticles were prepared by means of classical coprecipitation in solution in our laboratory. H-22 tumor cells suspended in phosphate-buffered saline (PBS, pH=7.2) were exposed to ultrasound at 1.37 MHz for up to 120 s in the presence of SPIOs. The cellular uptake of iron oxide nanoparticles was detected by prussion blue staining. The viability of cells was determined by a trypan blue exclusion test. At 2 W power and 60 s ultrasound exposure in presence of 410 {mu}g/ml SPIOs, H-22 cell labeling efficiency reached 69.4{+-}6.3% and the labeled cells exhibited an iron content of 10.38{+-}2.43 pg per cell. Furthermore, 95.2{+-}3.2% cells remained viable. The results indicated that the ultrasound protocol could be potentially applied to label cells with large-sized magnetic particles. We also calculated the shear stress at the 2 W power and 1.37 MHz used in experiments. The results showed that the shear stress threshold for ultrasonically induced H-22 cell reparable sonoporation was 697 Pa. These findings provide a quantitative guidance in designing ultrasound protocols for cell labeling. - Highlights: > High frequency focus ultrasound can be used as a safe method for instant magnetic labeling of cells. > 8-16 times increased efficiency can be gained by ultrasound versus that by transfection agents. > Calculation of shear stress around cells provide a quantitative design for ultrasound protocols.

  3. On-chip Magnetic Separation and Cell Encapsulation in Droplets

    Chen, A.; Byvank, T.; Bharde, A.; Miller, B. L.; Chalmers, J. J.; Sooryakumar, R.; Chang, W.-J.; Bashir, R.

    2012-02-01

    The demand for high-throughput single cell assays is gaining importance because of the heterogeneity of many cell suspensions, even after significant initial sorting. These suspensions may display cell-to-cell variability at the gene expression level that could impact single cell functional genomics, cancer, stem-cell research and drug screening. The on-chip monitoring of individual cells in an isolated environment could prevent cross-contamination, provide high recovery yield and ability to study biological traits at a single cell level These advantages of on-chip biological experiments contrast to conventional methods, which require bulk samples that provide only averaged information on cell metabolism. We report on a device that integrates microfluidic technology with a magnetic tweezers array to combine the functionality of separation and encapsulation of objects such as immunomagnetically labeled cells or magnetic beads into pico-liter droplets on the same chip. The ability to control the separation throughput that is independent of the hydrodynamic droplet generation rate allows the encapsulation efficiency to be optimized. The device can potentially be integrated with on-chip labeling and/or bio-detection to become a powerful single-cell analysis device.

  4. Large area magnetic micropallet arrays for cell colony sorting.

    Cox-Muranami, Wesley A; Nelson, Edward L; Li, G P; Bachman, Mark

    2016-01-01

    A new micropallet array platform for adherent cell colony sorting has been developed. The platform consisted of thousands of square plastic pallets, 270 μm by 270 μm on each side, large enough to hold a single colony of cells. Each pallet included a magnetic core, allowing them to be collected with a magnet after being released using a microscope mounted laser system. The micropallets were patterned from 1002F epoxy resist and were fabricated on translucent, gold coated microscope slides. The gold layer was used as seed for electroplating the ferromagnetic cores within every individual pallet. The gold layer also facilitated the release of each micropallet during laser release. This array allows for individual observation, sorting and collection of isolated cell colonies for biological cell colony research. In addition to consistent release and recovery of individual colonies, we demonstrated stable biocompatibility and minimal loss in imaging quality compared to previously developed micropallet arrays. PMID:26606460

  5. Biofunctionalized magnetic vortex microdisks for targeted cancer cell destruction.

    Kim, D.-H.; Rozhkova, E. A.; Ulasov, I. V.; Bader, S. D.; Rajh, T.; Lesniak, M. S.; Novosad, V.; Univ. of Chicago Pritzker School of Medicine

    2010-01-01

    Nanomagnetic materials offer exciting avenues for probing cell mechanics and activating mechanosensitive ion channels, as well as for advancing cancer therapies. Most experimental works so far have used superparamagnetic materials. This report describes a first approach based on interfacing cells with lithographically defined microdiscs that possess a spin-vortex ground state. When an alternating magnetic field is applied the microdisc vortices shift, creating an oscillation, which transmits a mechanical force to the cell. Because reduced sensitivity of cancer cells toward apoptosis leads to inappropriate cell survival and malignant progression, selective induction of apoptosis is of great importance for the anticancer therapeutic strategies. We show that the spin-vortex-mediated stimulus creates two dramatic effects: compromised integrity of the cellular membrane, and initiation of programmed cell death. A low-frequency field of a few tens of hertz applied for only ten minutes was sufficient to achieve {approx}90% cancer-cell destruction in vitro.

  6. Magnetically responsive yeast cells: methods of preparation and applications

    Šafařík, Ivo; Maděrová, Zdeňka; Pospišková, K.; Horská, Kateřina; Šafaříková, Miroslava

    2015-01-01

    Roč. 32, č. 1 (2015), s. 227-237. ISSN 0749-503X R&D Projects: GA MŠk(CZ) LD13023; GA MŠk(CZ) LD13021 Institutional support: RVO:67179843 Keywords : yeast cells * Saccharomyces * Kluyveromyces * Rhodotorula * Yarrowia * magnetic modification Subject RIV: EH - Ecology, Behaviour Impact factor: 1.634, year: 2014

  7. Magnetic domain wall conduits for single cell applications

    Donolato, Marco; Torti, A.; Kostesha, Natalie;

    2011-01-01

    The ability to trap, manipulate and release single cells on a surface is important both for fundamental studies of cellular processes and for the development of novel lab-on-chip miniaturized tools for biological and medical applications. In this paper we demonstrate how magnetic domain walls...

  8. Temperature increase in nanostructured cells of a magnetic tunnel junction during current-induced magnetization switching

    Three-dimensional numerical calculations based on the finite element method are performed to calculate the increase in the temperature in nanostructured cells of a magnetic tunnel junction under conditions that are relevant to current-induced magnetization switching for a high-density magnetic random access memory. Three key parameters, the lateral size, the resistance-area product and the applied current density, were varied widely so that their effects on the temperature increase could be examined. The computed results for the temperature increase, as a function of the resistance-area product and the current density, show the same trends that are expected from an equation for the dissipated heat. While the increase in the temperature is expected to be independent of the lateral size, the computations reveal a rather complicated relationship between the two variables, which is contingent on the various conditions that are considered. In a cell array that is relevant to high-density contexts, the temperature increase in the nearest cells is as high as 50% of the cell at which the current is directly applied; this could cause a thermal-stability problem in high-density magnetic random access memories. The temperature increase was also calculated under a more realistic physical picture of the relaxation of tunnelled electrons. These results are in agreement with those that are computed from Joule heating.

  9. Quantification of Non-Specific Binding of Magnetic Micro and Nano particles using Cell Tracking Velocimetry: Implication for magnetic cell separation and detection

    Chalmers, J. J.; Xiong, Y; X. Jin; Shao, M.; Tong, X; Farag, S.; Zborowski, M.

    2010-01-01

    The maturation of magnetic cell separation technology places increasing demands on magnetic cell separation performance. While a number of factors can cause suboptimal performance, one of the major challenges can be non-specific binding of magnetic nano or micro particles to non-targeted cells. Depending on the type of separation, this non-specific binding can have a negative effect on the final purity, the recovery of the targeted cells, or both. In this work, we quantitatively demonstrate t...

  10. Fundamentals and Application of Magnetic Particles in Cell Isolation and Enrichment

    Plouffe, Brian D.; Shashi K. Murthy; Lewis, Laura H.

    2014-01-01

    Magnetic sorting using magnetic beads has become a routine methodology for the separation of key cell populations from biological suspensions. Due to the inherent ability of magnets to provide forces at a distance, magnetic cell manipulation is now a standardized process step in numerous processes in tissue engineering, medicine, and in fundamental biological research. Herein we review the current status of magnetic particles to enable isolation and separation of cells, with a strong focus on...

  11. Local viscoelasticity of living cells measured by rotational magnetic spectroscopy

    Berret, J.-F.

    2016-01-01

    When submitted to a magnetic field, micron-size wires with superparamagnetic properties behave as embedded rheometers and represent interesting sensors for microrheology. Here we use rotational magnetic spectroscopy to measure the shear viscosity of the cytoplasm of living cells. We address the question of whether the cytoplasm is a viscoelastic liquid or an elastic gel. The main result of the study is the observation of a rotational instability between a synchronous and an asynchronous regime of rotation, found for murine fibroblasts and human cancer cells. For wires of susceptibility 3.6, the transition occurs in the range 0.01-1 rad s-1. The determination of the shear viscosity (10-100 Pa s) and elastic modulus (5-20 Pa) confirms the viscoelastic character of the cytoplasm. In contrast to earlier studies, it is concluded that the interior of living cells can be described as a viscoelastic liquid, and not as an elastic gel.

  12. Magnetic resonance imaging of ganglion cell tumours

    The MRI and CT studies of four patients with ganglion cell tumours, one with a cerebellar gangliocytoma (Lhermitte-Duclos disease), and three with gangliogliomas are reported. MRI in Lhermitte-Duclos disease clearly demonstrated a mass of low signal intensity in the left cerebellum on T1-weighted spin-echo (SE) images and an area of high signal intensity with a blurred margin on T2-weighted SE images. These MRI studies were useful for delineating the lesion, which was verified at surgery. In the ganglioglioma, MRI demonstrated two isointense solid masses on T1-weighted SE images, which enhanced clearly with Gd-DTPA. The enhancement study was advantageous in planning surgery. (orig.)

  13. Magnetic microfluidic system for isolation of single cells

    Mitterboeck, Richard; Kokkinis, Georgios; Berris, Theocharis; Keplinger, Franz; Giouroudi, Ioanna

    2015-06-01

    This paper presents the design and realization of a compact, portable and cost effective microfluidic system for isolation and detection of rare circulating tumor cells (CTCs) in suspension. The innovative aspect of the proposed isolation method is that it utilizes superparamagnetic particles (SMPs) to label CTCs and then isolate those using microtraps with integrated current carrying microconductors. The magnetically labeled and trapped CTCs can then be detected by integrated magnetic microsensors e.g. giant magnetoresistive (GMR) or giant magnetoimpedance (GMI) sensors. The channel and trap dimensions are optimized to protect the cells from shear stress and achieve high trapping efficiency. These intact single CTCs can then be used for additional analysis, testing and patient specific drug screening. Being able to analyze the CTCs metastasis-driving capabilities on the single cell level is considered of great importance for developing patient specific therapies. Experiments showed that it is possible to capture single labeled cells in multiple microtraps and hold them there without permanent electric current and magnetic field.

  14. Easily fabricated magnetic traps for single-cell applications

    Koschwanez, John H.; Carlson, Robert H.; Meldrum, Deirdre R.

    2007-04-01

    We describe a simple and inexpensive method of fabricating single cell magnetic traps within a polydimethylsiloxane (PDMS) device. These traps were developed as part of an automated system that captures individual yeast cells in a microfluidic device and analyzes each cell as it buds. To make the traps, PdCl2 catalyst is rubbed with vinyl foam onto plasma-patterned PDMS, and then Co-Ni-B alloy is electrolessly deposited onto the catalyst at a moderate temperature. We demonstrate individual yeast cell capture and estimate the capture force (1.9-4.4 pN) by measuring the flow speed required to remove the cell from its trap in a microfluidic channel.

  15. Enrichment of rat oligodendrocyte progenitor cells by magnetic cell sorting

    Čížková, D.; Čížek, M.; Nagyová, M.; Slovinská, L.; Novotná, I.; Jergová, S.; Radoňák, J.; Hlučilová, Jana; Vanický, I.

    2009-01-01

    Roč. 184, č. 1 (2009), s. 88-94. ISSN 0165-0270 R&D Projects: GA MŠk MEB0808108 Grant ostatní: Agentúra na podporu výskumu a vývoja(SK) APVV-51002105; Agentúra na podporu výskumu a vývoja(SK) APVV SK-CZ-0045-07 Institutional research plan: CEZ:AV0Z50450515 Keywords : Oligodendrocytes progenitors Lineage * Magnetic separation Subject RIV: FH - Neurology Impact factor: 2.295, year: 2009

  16. Cell Targeting and Magnetically Induced Hyperthermia

    Duguet, Etienne; Hardel, Lucile; Vasseur, Sébastien

    With the recent development of efficient and reproducible methods for synthesis, stable aqueous dispersions of individual particles can be prepared, in which the particle sizes can be accurately adjusted from a few nanometers to a few tens of nanometers [1]. Provided that their physical and chemical surface properties can be suitably adapted, these objects are small enough to circulate within the human body without risk of causing an embolus, since the finest capillaries (those of the lungs) have a minimal internal diameter of 5 μm. They can also escape from the blood compartment by windows of diameter around 100 nm in certain epithelia with permeability defects, such as those located in tumours and centers of infection, whereby they may then accumulate in such tissues. Furthermore, the smallest particles can migrate from the cardiovascular system into the lymph system. Finally, under the right conditions, they can enter cells and their various compartments. They should quickly become indispensable in the field of biological labelling, image contrast enhancement, the delivery of active principles, and the treatment of many different pathologies, by virtue of their novel physical properties [2, 3].

  17. Dyes adsorption on magnetically modified Chlorella vulgaris cells

    Šafaříková, Miroslava; Pona, B. M. R.; Mosiniewicz-Szablewska, E.; Weyda, František; Šafařík, Ivo

    2008-01-01

    Roč. 17, č. 4 (2008), s. 486-492. ISSN 1018-4619 R&D Projects: GA MŠk OC 108; GA MPO 2A-1TP1/094 Institutional research plan: CEZ:AV0Z60870520; CEZ:AV0Z50070508 Keywords : Chlorella vulgaris * magnetically modified cells * dyes Subject RIV: EI - Biotechnology ; Bionics Impact factor: 0.463, year: 2008

  18. Non-chemotoxic induction of cancer cell death using magnetic nanowires

    Contreras, Maria

    2015-03-01

    In this paper, we show that magnetic nanowires with weak magnetic fields and low frequencies can induce cell death via a mechanism that does not involve heat production. We incubated colon cancer cells with two concentrations (2.4 and 12 μg/mL) of nickel nanowires that were 35 nm in diameter and exposed the cells and nanowires to an alternating magnetic field (0.5 mT and 1 Hz or 1 kHz) for 10 or 30 minutes. This low-power field exerted a force on the magnetic nanowires, causing a mechanical disturbance to the cells. Transmission electron microscopy images showed that the nanostructures were internalized into the cells within 1 hour of incubation. Cell viability studies showed that the magnetic field and the nanowires separately had minor deleterious effects on the cells; however, when combined, the magnetic field and nanowires caused the cell viability values to drop by up to 39%, depending on the strength of the magnetic field and the concentration of the nanowires. Cell membrane leakage experiments indicated membrane leakage of 20%, suggesting that cell death mechanisms induced by the nanowires and magnetic field involve some cell membrane rupture. Results suggest that magnetic nanowires can kill cancer cells. The proposed process requires simple and low-cost equipment with exposure to only very weak magnetic fields for short time periods. © 2015 Contreras et al.

  19. Low-magnetization magnetic microcapsules: A synergistic theranostic platform for remote cancer cells therapy and imaging

    Zhang, Wei

    2014-04-02

    Multifunctional magnetic microcapsules (MMCs) for the combined cancer cells hyperthermia and chemotherapy in addition to MR imaging are successfully developed. A classical layer-by-layer technique of oppositely charged polyelectrolytes (poly(allylamine hydrochloride) (PAH) and poly(4-styrene sulfonate sodium) (PSS)) is used as it affords great controllability over the preparation together with enhanced loading of the chemotherapeutic drug (doxorubicin, DOX) in the microcapsules. Superparamagnetic iron oxide (SPIOs) nanoparticles are layered in the system to afford MMC1 (one SPIOs layer) and MMC2 (two SPIOs layers). Most interestingly, MMC1 and MMC2 show efficient hyperthermia cell death and controlled DOX release although their magnetic saturation value falls below 2.5 emu g-1, which is lower than the 7-22 emu g-1 reported to be the minimum value needed for biomedical applications. Moreover, MMCs are pH responsive where a pH 5.5 (often reported for cancer cells) combined with hyperthermia increases DOX release predictably. Both systems prove viable when used as T2 contrast agents for MR imaging in HeLa cells with high biocompatibility. Thus, MMCs hold a great promise to be used commercially as a theranostic platform as they are controllably prepared, reproducibly enhanced, and serve as drug delivery, hyperthermia, and MRI contrast agents at the same time.

  20. Biomedical Applications of Magnetic Nanoparticles: Delivering Genes and Remote Control of Cells

    Dobson, Jon

    2013-03-01

    The use of magnetic micro- and nanoparticles for biomedical applications was first proposed in the 1920s as a way to measure the rehological properties of the cell's cytoplasm. Since that time, magnetic micro- and nanoparticle synthesis, coating and bio-functionalization have advanced significantly, as have the applications for these particles. Magnetic micro- and nanoparticles are now used in a variety of biomedical techniques such as targeted drug delivery, MRI contrast enhancement, gene transfection, immno-assay and cell sorting. More recently, magnetic micro- and nanoparticles have been used to investigate and manipulate cellular processes both in vitro and in vivo. This talk will focus on magnetic nanoparticle targeting to and actuation of cell surface receptors to control cell signaling cascades to control cell behavior. This technology has applications in disease therapy, cell engineering and regenerative medicine. The use of magnetic nanoparticles and oscillating magnet arrays for enhanced gene delivery will also be discussed.

  1. Cell death induced by the application of alternating magnetic fields to nanoparticle-loaded dendritic cells

    Marcos-Campos, I.; Asín, L.; Torres, T. E.; Marquina, C.; Tres, A.; Ibarra, M. R.; Goya, G. F.

    2011-05-01

    In this work, the capability of primary, monocyte-derived dendritic cells (DCs) to uptake iron oxide magnetic nanoparticles (MNPs) is assessed and a strategy to induce selective cell death in these MNP-loaded DCs using external alternating magnetic fields (AMFs) is reported. No significant decrease in the cell viability of MNP-loaded DCs, compared to the control samples, was observed after five days of culture. The number of MNPs incorporated into the cytoplasm was measured by magnetometry, which confirmed that 1-5 pg of the particles were uploaded per cell. The intracellular distribution of these MNPs, assessed by transmission electron microscopy, was found to be primarily inside the endosomic structures. These cells were then subjected to an AMF for 30 min and the viability of the blank DCs (i.e. without MNPs), which were used as control samples, remained essentially unaffected. However, a remarkable decrease of viability from approximately 90% to 2-5% of DCs previously loaded with MNPs was observed after the same 30 min exposure to an AMF. The same results were obtained using MNPs having either positive (NH2 + ) or negative (COOH - ) surface functional groups. In spite of the massive cell death induced by application of AMF to MNP-loaded DCs, the number of incorporated magnetic particles did not raise the temperature of the cell culture. Clear morphological changes at the cell structure after magnetic field application were observed using scanning electron microscopy. Therefore, local damage produced by the MNPs could be the main mechanism for the selective cell death of MNP-loaded DCs under an AMF. Based on the ability of these cells to evade the reticuloendothelial system, these complexes combined with an AMF should be considered as a potentially powerful tool for tumour therapy.

  2. Cell death induced by the application of alternating magnetic fields to nanoparticle-loaded dendritic cells

    In this work, the capability of primary, monocyte-derived dendritic cells (DCs) to uptake iron oxide magnetic nanoparticles (MNPs) is assessed and a strategy to induce selective cell death in these MNP-loaded DCs using external alternating magnetic fields (AMFs) is reported. No significant decrease in the cell viability of MNP-loaded DCs, compared to the control samples, was observed after five days of culture. The number of MNPs incorporated into the cytoplasm was measured by magnetometry, which confirmed that 1-5 pg of the particles were uploaded per cell. The intracellular distribution of these MNPs, assessed by transmission electron microscopy, was found to be primarily inside the endosomic structures. These cells were then subjected to an AMF for 30 min and the viability of the blank DCs (i.e. without MNPs), which were used as control samples, remained essentially unaffected. However, a remarkable decrease of viability from approximately 90% to 2-5% of DCs previously loaded with MNPs was observed after the same 30 min exposure to an AMF. The same results were obtained using MNPs having either positive (NH2+) or negative (COOH-) surface functional groups. In spite of the massive cell death induced by application of AMF to MNP-loaded DCs, the number of incorporated magnetic particles did not raise the temperature of the cell culture. Clear morphological changes at the cell structure after magnetic field application were observed using scanning electron microscopy. Therefore, local damage produced by the MNPs could be the main mechanism for the selective cell death of MNP-loaded DCs under an AMF. Based on the ability of these cells to evade the reticuloendothelial system, these complexes combined with an AMF should be considered as a potentially powerful tool for tumour therapy.

  3. Cell death induced by the application of alternating magnetic fields to nanoparticle-loaded dendritic cells

    Marcos-Campos, I; AsIn, L; Torres, T E; Tres, A; Ibarra, M R; Goya, G F [Instituto de Nanociencia de Aragon (INA), Mariano Esquillor s/n, CP 50018, Zaragoza (Spain); Marquina, C, E-mail: goya@unizar.es [Condensed Matter Department, Sciences Faculty, University of Zaragoza, 50009 (Spain)

    2011-05-20

    In this work, the capability of primary, monocyte-derived dendritic cells (DCs) to uptake iron oxide magnetic nanoparticles (MNPs) is assessed and a strategy to induce selective cell death in these MNP-loaded DCs using external alternating magnetic fields (AMFs) is reported. No significant decrease in the cell viability of MNP-loaded DCs, compared to the control samples, was observed after five days of culture. The number of MNPs incorporated into the cytoplasm was measured by magnetometry, which confirmed that 1-5 pg of the particles were uploaded per cell. The intracellular distribution of these MNPs, assessed by transmission electron microscopy, was found to be primarily inside the endosomic structures. These cells were then subjected to an AMF for 30 min and the viability of the blank DCs (i.e. without MNPs), which were used as control samples, remained essentially unaffected. However, a remarkable decrease of viability from approximately 90% to 2-5% of DCs previously loaded with MNPs was observed after the same 30 min exposure to an AMF. The same results were obtained using MNPs having either positive (NH{sub 2}{sup +}) or negative (COOH{sup -}) surface functional groups. In spite of the massive cell death induced by application of AMF to MNP-loaded DCs, the number of incorporated magnetic particles did not raise the temperature of the cell culture. Clear morphological changes at the cell structure after magnetic field application were observed using scanning electron microscopy. Therefore, local damage produced by the MNPs could be the main mechanism for the selective cell death of MNP-loaded DCs under an AMF. Based on the ability of these cells to evade the reticuloendothelial system, these complexes combined with an AMF should be considered as a potentially powerful tool for tumour therapy.

  4. Magnetic separation of particles and cells in ferrofluid flow through a straight microchannel using two offset magnets

    The separation of particles and cells is critical in many chemical and biological applications. This work presents a simple idea for utilizing a pair of permanent magnets to continuously separate diamagnetic particles and cells in ferrofluid flow through a straight microchannel. The first magnet is placed close to the microchannel for focusing the particle mixture to a single stream without the use of a sheath flow. The second magnet, which is offset from the first magnet and placed farther from the channel, is to displace the aligned particles to dissimilar flow paths for a continuous sorting. This idea is first demonstrated through the separation of 3 μm- and 10 μm-diameter polystyrene particles, where the effects of flow speed and magnet distance are both examined. The experimental data are found to fit well with the predictions of an analytical model. Furthermore, a continuous separation of live yeast cells from 10 μm polystyrene particles is implemented in the same device. - Highlights: • We develop a simple diamagnetic particle and cell separation technique in ferrofluids. • Two offset magnets are used to achieve a sheath-free continuous separation in a straight microchannel. • The technique is demonstrated through the magnetic separation of polystyrene particles and yeast cells. • The effects of ferrofluid speed and magnet-channel distance are examined on particle separation. • The predictions from an analytical model agree with the experimental data quantitatively

  5. Magnetic separation of particles and cells in ferrofluid flow through a straight microchannel using two offset magnets

    Zeng, Jian; Deng, Yanxiang [Department of Mechanical Engineering, Clemson University, Clemson, SC 29634-0921 (United States); Vedantam, Pallavi; Tzeng, Tzuen-Rong [Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314 (United States); Xuan, Xiangchun, E-mail: xcxuan@clemson.edu [Department of Mechanical Engineering, Clemson University, Clemson, SC 29634-0921 (United States)

    2013-11-15

    The separation of particles and cells is critical in many chemical and biological applications. This work presents a simple idea for utilizing a pair of permanent magnets to continuously separate diamagnetic particles and cells in ferrofluid flow through a straight microchannel. The first magnet is placed close to the microchannel for focusing the particle mixture to a single stream without the use of a sheath flow. The second magnet, which is offset from the first magnet and placed farther from the channel, is to displace the aligned particles to dissimilar flow paths for a continuous sorting. This idea is first demonstrated through the separation of 3 μm- and 10 μm-diameter polystyrene particles, where the effects of flow speed and magnet distance are both examined. The experimental data are found to fit well with the predictions of an analytical model. Furthermore, a continuous separation of live yeast cells from 10 μm polystyrene particles is implemented in the same device. - Highlights: • We develop a simple diamagnetic particle and cell separation technique in ferrofluids. • Two offset magnets are used to achieve a sheath-free continuous separation in a straight microchannel. • The technique is demonstrated through the magnetic separation of polystyrene particles and yeast cells. • The effects of ferrofluid speed and magnet-channel distance are examined on particle separation. • The predictions from an analytical model agree with the experimental data quantitatively.

  6. Magnetic resonance imaging in the staging of renal cell carcinoma

    Eighteen patients with renal neoplasm underwent magnetic resonance imaging (MRI) using a 1.5 Tesla superconducting magnetic system and spin echo images were obtained by quick scan technique under holding breath. MR images were interpreted independently of the computerized tomography (CT) findings. The preoperative stagings of the 18 renal carcinomas, as judged by MRI, were compared with those obtained at laparotomy. The anatomic staging was correctly performed by MRI in 13 patients (72 %). In the patients who had intrarenal small tumor with normal renal contour, MRI demonstrated a solid mass clearly distinguishable from surrounding renal parenchyma using the paramagnetic contrast agent (gadolinium-DTPA). When compared with results of evaluation by CT in staging, MRI appeared to have several advantages in determination of whole mass; the detection of tumor thrombus into renal vein and inferior vena cava; and the evaluation of direct tumor invasion of adjacent organs. MRI should play an important role in the staging of renal cell carcinoma. (author)

  7. Effects of Magnetic Fluid Hyperthermia Induced by An Alternative Magnetic Field on Human Carcinoma A549 Cell in vitro

    Guoqing WANG

    2011-03-01

    Full Text Available Background and objective Magnetic fluid hyperthermia (MFH is a method of heat therapy using nanometer techniques and hyperthermia. It has the advantage of high specificity of targeting. The aim of this study is to detect the effects of MFH induced by an alternating magnetic field on human being carcinoma A549 cells in vitro. Methods A human adenocarcinoma cell line A549 was cultured with various concentrations of ferroferric oxide (Fe3O4 magnetic fluid (1.5-6.0 mg/mL and exposed to an alternative magnetic field (AMF for 30 min. And then the optical density (OD of viable cell, cytotocixity index, growth curve of cells, morphologic changes of cell, cell cycle and aposptosis were measured. Results The proliferation of the A549 cells were remarkably inhibited, the OD value of viable cells decreased and cytotoxity index (CI increased; Apoptosis of the A549 cells were observed to have cell shrinkage, chromatin condensation, margination, unclear fragmentation and intact cell membrane by light and electron microscopy; The cells were inhibited in the stage S. Conclusion MFH induced by AMF could inhibit the proliferation, which promotes apoptosis and arrest at S stage of the A549 cells.

  8. Individual Mammalian Cell Magnetic Measurements with a Superconducting Quantum Interference Device

    Palmstrom, Johanna C.; Brewer, Kimberly; Tee, Sui Seng; Theis, Eric; Rutt, Brian; Moler, Kathryn A.

    2015-03-01

    Magnetism can be introduced into otherwise nonmagnetic cells by the uptake of superparamagnetic iron oxide (SPIO) nanoparticles. SPIO nanoparticles are used in numerous biomedical applications including cellular therapies and targeted drug delivery. Currently there are few tools capable of characterizing individual magnetic nanoparticles and the magnetic properties of individual mammalian cells loaded with SPIO. Our scanning superconducting quantum interference devices (SQUIDs) are good candidates for these measurements due to their high sensitivity to magnetic dipole moments (approx. 200 μb/ √Hz) In this study, we use a scanning SQUID to image the magnetic flux from SPIO loaded H1299 lung cancer cells. We find that the magnetic moment spatially varies inside the cell with each cell having a unique distribution of moments. We also correlate these magnetic images with optical and scanning electron microscope images. These results show that the SQUID is a useful tool for imaging biological magnetism. The visualization of single cell magnetism and the quantification of magnetic dipole moments in magnetically labeled cells can be used to optimize conventional biological magnetic imaging techniques, such as MRI.

  9. Fundamentals and application of magnetic particles in cell isolation and enrichment: a review

    Magnetic sorting using magnetic beads has become a routine methodology for the separation of key cell populations from biological suspensions. Due to the inherent ability of magnets to provide forces at a distance, magnetic cell manipulation is now a standardized process step in numerous processes in tissue engineering, medicine, and in fundamental biological research. Herein we review the current status of magnetic particles to enable isolation and separation of cells, with a strong focus on the fundamental governing physical phenomena, properties and syntheses of magnetic particles and on current applications of magnet-based cell separation in laboratory and clinical settings. We highlight the contribution of cell separation to biomedical research and medicine and detail modern cell-separation methods (both magnetic and non-magnetic). In addition to a review of the current state-of-the-art in magnet-based cell sorting, we discuss current challenges and available opportunities for further research, development and commercialization of magnetic particle-based cell-separation systems. (review article)

  10. GEMPIC: Geometric ElectroMagnetic Particle-In-Cell Methods

    Kraus, Michael; Morrison, Philip J; Sonnendrücker, Eric

    2016-01-01

    We present a novel framework for Finite Element Particle-in-Cell methods based on the discretization of the underlying Hamiltonian structure of the Vlasov-Maxwell system. We derive a semi-discrete Poisson bracket, which satisfies the Jacobi identity , and apply Hamiltonian splitting schemes for time integration. Techniques from Finite Element Exterior Calculus ensure conservation of the divergence of the magnetic field and Gauss' law as well as stability of the field solver. The resulting methods are gauge-invariant, feature exact charge conservation and show excellent long-time energy and momentum behavior.

  11. Preparation of Immuno-magnetic Beads and Their Separation & Detection to Ovary Cancer Cells

    2001-01-01

    The organic monomer-molecule with nanometer magnetic powder by means of reforming the surface of nanometer magnetic powder have been synthesized.Magnetic beads in diameter of 2μm or so are obtained by controlling conditions.Ovary cancer cells of ascites are separated and ovary cancer cells of blood are detected by using immuno-magnetic beads linked with ovary cancer cell mono-antibodies.Results show that the specificity is 85%,sensitivity is 87%,accuracy is 84%,cells acquiring purity is 90%,cells activity is 92% and detection sensitivity is 25×10-7.

  12. Removal of malaria-infected red blood cells using magnetic cell separators: A computational study.

    Kim, Jeongho; Massoudi, Mehrdad; Antaki, James F; Gandini, Alberto

    2012-02-15

    High gradient magnetic field separators have been widely used in a variety of biological applications. Recently, the use of magnetic separators to remove malaria-infected red blood cells (pRBCs) from blood circulation in patients with severe malaria has been proposed in a dialysis-like treatment. The capture efficiency of this process depends on many interrelated design variables and constraints such as magnetic pole array pitch, chamber height, and flow rate. In this paper, we model the malaria-infected RBCs (pRBCs) as paramagnetic particles suspended in a Newtonian fluid. Trajectories of the infected cells are numerically calculated inside a micro-channel exposed to a periodic magnetic field gradient. First-order stiff ordinary differential equations (ODEs) governing the trajectory of particles under periodic magnetic fields due to an array of wires are solved numerically using the 1(st) -5(th) order adaptive step Runge-Kutta solver. The numerical experiments show that in order to achieve a capture efficiency of 99% for the pRBCs it is required to have a longer length than 80 mm; this implies that in principle, using optimization techniques the length could be adjusted, i.e., shortened to achieve 99% capture efficiency of the pRBCs. PMID:22345827

  13. Magnetic targeting of iron-oxide-labeled fluorescent hepatoma cells to the liver

    The purpose of this study was to determine whether an external magnet field can induce preferential trafficking of magnetically labeled Huh7 hepatoma cells to the liver following liver cell transplantation. Huh7 hepatoma cells were labeled with anionic magnetic nanoparticles (AMNP) and tagged with a fluorescent membrane marker (PKH67). Iron-uptake was measured by magnetophoresis. Twenty C57Bl6 mice received an intrasplenic injection of 2 x 106 labeled cells. An external magnet (0.29 T; 25 T/m) was placed over the liver of 13 randomly selected animals (magnet group), while the remaining 7 animals served as controls. MRI (1.5 T) and confocal fluorescence microscopy (CFM) were performed 10 days post-transplantation. The presence and location of labeled cells within the livers were compared in the magnet group and controls, and confronted with histological analysis representing the standard of reference. Mean iron content per cell was 6 pg. Based on histology, labeled cells were more frequently present within recipient livers in the magnet group (p < 0.01) where their distribution was preferentially peri-vascular (p<0.05). MRI and CFM gave similar results for the overall detection of transplanted cells (kappa=0.828) and for the identification of peri-vascular cells (kappa=0.78). Application of an external magnet can modify the trafficking of transplanted cells, especially by promoting the formation of perivascular aggregates. (orig.)

  14. Magnetic relaxometry with an atomic magnetometer and SQUID sensors on targeted cancer cells

    Johnson, Cort [Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185 (United States); Adolphi, Natalie L. [Department of Biochemistry and Molecular Biology, University of New Mexico, Albuquerque, NM 87131 (United States); Butler, Kimberly L.; Lovato, Debbie M.; Larson, Richard [Department of Pathology, University of New Mexico, Cancer Research and Treatment Center, Albuquerque, NM 87131 (United States); Schwindt, Peter D.D. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185 (United States); Flynn, Edward R., E-mail: seniorsci@comcast.net [Senior Scientific, LLC, 11109 Country Club NE, Albuquerque, NM 87111 (United States)

    2012-08-15

    Magnetic relaxometry methods have been shown to be very sensitive in detecting cancer cells and other targeted diseases. Superconducting quantum interference device (SQUID) sensors are one of the primary sensor systems used in this methodology because of their high sensitivity with demonstrated capabilities of detecting fewer than 100,000 magnetically-labeled cancer cells. The emerging technology of atomic magnetometers (AMs) represents a new detection method for magnetic relaxometry with high sensitivity and without the requirement for cryogens. We report here on a study of magnetic relaxometry using both AM and SQUID sensors to detect cancer cells that are coated with superparamagnetic nanoparticles through antibody targeting. The AM studies conform closely to SQUID sensor results in the measurement of the magnetic decay characteristics following a magnetization pulse. The AM and SQUID sensor data are well described theoretically for superparamagnetic particles bound to cells and the results can be used to determine the number of cells in a cell culture or tumor. The observed fields and magnetic moments of cancer cells are linear with the number of cells over a very large range. The AM sensor demonstrates very high sensitivity for detecting magnetically labeled cells, does not require cryogenic cooling and is relatively inexpensive. - Highlights: Black-Right-Pointing-Pointer Magnetic relaxometry is used to study antibody targeted nanoparticles and cells. Black-Right-Pointing-Pointer Atomic magnetometer and SQUID sensor performances are compared. Black-Right-Pointing-Pointer High sensitivity of magnetic relaxometry for cancer cell detection is demonstrated. Black-Right-Pointing-Pointer Magnetic relaxometry decay curves from cancer cells are fit by a log function.

  15. Magnetic relaxometry with an atomic magnetometer and SQUID sensors on targeted cancer cells

    Magnetic relaxometry methods have been shown to be very sensitive in detecting cancer cells and other targeted diseases. Superconducting quantum interference device (SQUID) sensors are one of the primary sensor systems used in this methodology because of their high sensitivity with demonstrated capabilities of detecting fewer than 100,000 magnetically-labeled cancer cells. The emerging technology of atomic magnetometers (AMs) represents a new detection method for magnetic relaxometry with high sensitivity and without the requirement for cryogens. We report here on a study of magnetic relaxometry using both AM and SQUID sensors to detect cancer cells that are coated with superparamagnetic nanoparticles through antibody targeting. The AM studies conform closely to SQUID sensor results in the measurement of the magnetic decay characteristics following a magnetization pulse. The AM and SQUID sensor data are well described theoretically for superparamagnetic particles bound to cells and the results can be used to determine the number of cells in a cell culture or tumor. The observed fields and magnetic moments of cancer cells are linear with the number of cells over a very large range. The AM sensor demonstrates very high sensitivity for detecting magnetically labeled cells, does not require cryogenic cooling and is relatively inexpensive. - Highlights: ► Magnetic relaxometry is used to study antibody targeted nanoparticles and cells. ► Atomic magnetometer and SQUID sensor performances are compared. ► High sensitivity of magnetic relaxometry for cancer cell detection is demonstrated. ► Magnetic relaxometry decay curves from cancer cells are fit by a log function.

  16. Harvesting of Dunaliella tertiolecta cells by magnetic filtration

    Manousakis, Emmanouil; Manariotis, Ioannis D.

    2015-04-01

    The rising cost and reduced reserves of fossil fuels have enhanced the interest for finding alterative energy sources. Microalgae are considered to be the only sustainable option in biodiesel production for two key points. The energy yield from microalgae is much higher than that of oil producing crops, and the cultivation of algae it is not antagonistic with food supply chain. Because of the small size of microalgae and the dilute nature of algal cultures, the harvesting cost of microalgae is so far a limiting step for the scale up of microalgal biofuel production. It is estimated that the algal harvesting cost is at least 20-30% of the total biomass production cost. Traditional methods, which have been employed for the recovery of microalgal biomass, include centrifugation, gravity separation, filtration, flocculation, and flotation. Alternative approaches, other than conventional methods, capable of processing large cultures volume at a low cost, and reducing effluent toxicity are essential for microalgal biomass production. Magnetic separation is a promising technology and has been applied for algal removal in the mid of 1970s. The aim of this study was to investigate the harvesting of microalgae cells using magnetic microparticles (MPs). Dunaliella tertiolecta was selected as a representative for marine microalgae. The cultivation of microalgae was conducted under continuous artificial light, in 20 L flasks. Iron oxide microparticles were prepared by microwave irradiation of FeSO4 7H2O in an alkaline solution. Samples were taken at different operation intervals to conduct harvesting studies. Batch and flow-through experiments were conducted in order to investigate the effect of the magnetic material on microalgae removal. Algal removal in flow through experiments ranged from 70 to 85% depending on the initial MPs concentration even at very short hydraulic retention times (i.e. 2 min). In batch tests, algal removal was up to 97% at MPs concentration of 490 mg/L.

  17. Experimental studies on ultralow frequency pulsed gradient magnetic field inducing apoptosis of cancer cell and inhibiting growth of cancer cell

    曾繁清; 郑从义; 张新晨; 李宗山; 李朝阳; 王川婴; 张新松; 黄晓玲; 张沪生

    2002-01-01

    The morphology characteristics of cell apoptosis of the malignant tumour cells in magnetic field-treated mouse was observed for the first time. The apoptotic cancer cell contracted, became rounder and divorced from adjacent cells; the heterochromatin condensed and coagulated together along the inner side of the nuclear membrane; the endoplasmic reticulums(ER) expanded and fused with the cellular membrane; many apoptotic bodies which were packed by the cellular membrane appeared and were devoured by some lymphocytes and plasma. Apoptosis of cancer cells was detected by terminal deoxynucleotidyl transferase mediated in situ nick end labeling(TUNEL). It was found that the number of apoptosis cancer cells of the sample treated by the magnetic field is more than that of the control sample. The growth of malignant tumour in mice was inhibited and the ability of immune cell to dissolve cancer cells was improved by ultralow frequency(ULF) pulsed gradient magnetic field; the nuclei DNA contents decreased, indicating that magnetic field can block DNA replication and inhibit mitosis of cancer cells. It was suggested that magnetic field could inhibit the metabolism of cancer cell, lower its malignancy, and restrain its rapid and heteromorphic growth. Since ULF pulsed gradient magnetic field can induce apoptosis of cancer cells and inhibit the growth of malignant tumour, it could be used as a new method to treat cancer.

  18. The measurement of small magnetic signals from magnetic nanoparticles attached to the cell surface and surrounding living cells using a general-purpose SQUID magnetometer

    Hashimoto, S; Oda, T; Yamada, K; Takagi, M; Enomoto, T; Ohkohchi, N [Department of Surgery, Advanced Biomedical Applications, Graduate School of Comprehensive Human Science, University of Tsukuba, Tsukuba, Ibaraki 305-8575 (Japan); Takagi, T; Kanamori, T [Research Center of Advanced Bionics, National Institute of Advanced Industrial Science and Technology (AIST), Central 5th, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan); Ikeda, H [Cryogenics Division, Research Facility Center for Science and Technology, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); Yanagihara, H; Kita, E; Tasaki, A [Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan)], E-mail: tatoda@md.tsukuba.ac.jp

    2009-04-21

    Magnetic nanoparticles have recently been widely applied in the bio-medical field. Responding to the demand for a simple and sensitive magnetic assay system for bio-liquid samples, we employed a general-purpose superconducting quantum interference device (SQUID) magnetometer. Strips of filter paper were used as a liquid-specimen sample holder possessing a very small magnetic background signal. An aqueous solution of superparamagnetic iron-oxide nanoparticles (Resovist (registered) ) was dropped in a tiny blot-like spot in the middle of the filter paper and the magnetization was measured. Magnetic moments of a dilution series of Resovist (registered) solutions versus the number of particles provided a linear graph, revealing that the magnetic moment per Resovist (registered) particle was 8.25 x 10{sup -17} emu. 1 x 10{sup 5} cancer cells were incubated with Resovist (registered) , and the number of Resovist (registered) particles attached to the cell surface and surrounding a living cell was calculated to be 1.02 {+-} 0.14 x 10{sup 7} particles/cell. Our system using a commercial SQUID magnetometer should be more than enough to determine the number of magnetic nanoparticles biologically reacting with living cells, contributing to the application of magneto nanomaterials to the life-science field.

  19. The measurement of small magnetic signals from magnetic nanoparticles attached to the cell surface and surrounding living cells using a general-purpose SQUID magnetometer

    Hashimoto, S.; Oda, T.; Yamada, K.; Takagi, M.; Enomoto, T.; Ohkohchi, N.; Takagi, T.; Kanamori, T.; Ikeda, H.; Yanagihara, H.; Kita, E.; Tasaki, A.

    2009-04-01

    Magnetic nanoparticles have recently been widely applied in the bio-medical field. Responding to the demand for a simple and sensitive magnetic assay system for bio-liquid samples, we employed a general-purpose superconducting quantum interference device (SQUID) magnetometer. Strips of filter paper were used as a liquid-specimen sample holder possessing a very small magnetic background signal. An aqueous solution of superparamagnetic iron-oxide nanoparticles (Resovist®) was dropped in a tiny blot-like spot in the middle of the filter paper and the magnetization was measured. Magnetic moments of a dilution series of Resovist® solutions versus the number of particles provided a linear graph, revealing that the magnetic moment per Resovist® particle was 8.25 × 10-17 emu. 1 × 105 cancer cells were incubated with Resovist®, and the number of Resovist® particles attached to the cell surface and surrounding a living cell was calculated to be 1.02 ± 0.14 × 107 particles/cell. Our system using a commercial SQUID magnetometer should be more than enough to determine the number of magnetic nanoparticles biologically reacting with living cells, contributing to the application of magneto nanomaterials to the life-science field.

  20. EFFECTS OF CARBOXYMETHLY DEXTRAN MAGNETIC NANOPARTICLES CARRIER SYSTEM ASSOCIATED WITH EXTERNAL MAGNETIC FIELDS ON KILLING TUMOR CELLS AND GENE TRANSFECTION

    CAO Zheng-guo; ZHOU Si-wei; LIU Ji-hong

    2005-01-01

    Objective: To investigate the preparation of the carboxymethly dextran iron oxide magnetic nanoparticles (CDMN) and the effects of CDMN carrier system associated with external magnetic fields on killing tumor cells and gene transfection in vitro. Methods: Epirubicin-CDMN (EPI-CDMN) and green fluorescent protein (GFP) plasmid-CDMN (GFP-CDMN) were prepared by the oxidation-reduction procedure and their characters were detected, respectively. The effects of EPI-CDMN associated with external pulsed electromagnetic fields (PEMFs) (10 mT) on killing human bladder cancer BIU-87 cells were studied by MTT assay and Annexin-V/PI double-labeled flow cytometry technique, respectively. And the transfection efficiency of GFP when CDMN were used as gene carrier associated with the external magnetic fields was evaluated under fluorescence microscope in vitro. Results: The diameter of EPI-CDMN and GFP-CDMN were about 8~10 nm and 5~9 nm, respectively, and saturation magnetization were 0.22 emu/g and 0.26 emu/g, respectively. EPI-CDMN associated with PEMFs could significantly inhibit the proliferation of BIU-87 cells and induce cells apoptosis, the growth inhibitory rate and apoptosis rate were (21.82(3.18)% and (16.79(3.37)%, respectively. The transfection efficiency of GFP-CDMN combined with PEMFs was significant higher than that of GFP-CDMN without PEMFs [(45.70(4.32)% vs (35.85(2.16)%, P<0.05]. Conclusion: It seemed that EPI-CDMN associated with external magnetic fields could significantly killed human bladder cancer BIU-87 cells and CDMN could effectively transfer GFP gene into tumors cells with the help of external magnetic fields which provided experimental basis for the magnetic targeting therapy of tumor.

  1. Apoptosis selectively induced in BEL-7402 cells by folic acid-modified magnetic nanoparticles combined with 100 Hz magnetic field

    Wen J

    2014-04-01

    Full Text Available Jian Wen,1 Shulian Jiang,1 Zhiqiang Chen,1 Wei Zhao,1 Yongxiang Yi,1 Ruili Yang,1 Baoan Chen2 1Second Affiliated Hospital of Southeast University, 2Department of Hematology, Zhongda Hospital, Medical School, Southeast University, Nanjing, People's Republic of China Objective: To explore the effect of folic acid-modified magnetic nanoparticles (FA-MNPs combined with a 100 Hz extremely low-frequency electromagnetic field (ELF-EMF on the apoptosis of liver cancer BEL-7402 cells. Materials and methods: MNPs (20 nm were prepared by coprecipitation, and then folic acid was coated onto MNPs to prepare FA-MNPs. BEL-7402 cells and HL7702 cells were selected as liver cancer cells and normal liver cells, respectively. The ELF-EMF was generated from a solenoid coil. Cellular uptake of NPs was determined by inductively coupled plasma atomic emission spectroscopy. A 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide assay was used to evaluate cell inhibition. Apoptosis was analyzed by flow cytometry. Statistical analyses were performed using two-way analysis of variance. Results: FA-MNPs combined with a 100 Hz magnetic field significantly inhibited cell proliferation and induced higher apoptosis compared to either the ELF-EMF alone or FA-MNPs alone. FA-MNPs showed a better apoptosis effect and higher iron uptake in BEL-7402 cells compared to in HL7702 cells. On the basis of the ELF-EMF, higher doses of FA-MNPs brought higher apoptosis and higher iron uptake in either BEL-7402 cells or HL7702 cells. Conclusion: These results suggest that FA-MNPs may induce apoptosis in a cellular iron uptake-dependent manner when combined with an ELF-EMF in BEL-7402 cells.Keywords: extremely low-frequency magnetic field, magnetic nanoparticle, apoptosis, liver cancer, folic acid

  2. Yeast cells proliferation on various strong static magnetic fields and temperatures

    Otabe, E. S.; Kuroki, S.; Nikawa, J.; Matsumoto, Y.; Ooba, T.; Kiso, K.; Hayashi, H.

    2009-03-01

    The effect of strong magnetic fields on activities of yeast cells were investigated. Experimental yeast cells were cultured in 5 ml of YPD(Yeast extract Peptone Dextrose) for the number density of yeast cells of 5.0 ±0.2 x 106/ml with various temperatures and magnetic fields up to 10 T. Since the yeast cells were placed in the center of the superconducting magnet, the effect of magnetic force due to the diamagnetism and magnetic gradient was negligibly small. The yeast suspension was opened to air and cultured in shaking condition. The number of yeast cells in the yeast suspension was counted by a counting plate with an optical microscope, and the time dependence of the number density of yeast cells was measured. The time dependence of the number density of yeast cells, ρ, of initial part is analyzed in terms of Malthus equation as given by ρ = ρo exp(kt), where k is the growth coefficient. It is found that, the growth coefficient under the magnetic field is suppressed compared with the control. The growth coefficient decreasing as increasing magnetic field and is saturated at about 5 T. On the other hand, it is found that the suppression of growth of yeast cells by the magnetic field is diminished at high temperatures.

  3. Yeast cells proliferation on various strong static magnetic fields and temperatures

    The effect of strong magnetic fields on activities of yeast cells were investigated. Experimental yeast cells were cultured in 5 ml of YPD(Yeast extract Peptone Dextrose) for the number density of yeast cells of 5.0 ±0.2 x 106/ml with various temperatures and magnetic fields up to 10 T. Since the yeast cells were placed in the center of the superconducting magnet, the effect of magnetic force due to the diamagnetism and magnetic gradient was negligibly small. The yeast suspension was opened to air and cultured in shaking condition. The number of yeast cells in the yeast suspension was counted by a counting plate with an optical microscope, and the time dependence of the number density of yeast cells was measured. The time dependence of the number density of yeast cells, ρ, of initial part is analyzed in terms of Malthus equation as given by ρ = ρo exp(kt), where k is the growth coefficient. It is found that, the growth coefficient under the magnetic field is suppressed compared with the control. The growth coefficient decreasing as increasing magnetic field and is saturated at about 5 T. On the other hand, it is found that the suppression of growth of yeast cells by the magnetic field is diminished at high temperatures.

  4. One-step magnetic modification of yeast cells by microwave-synthesized iron oxide microparticles

    Pospišková, K.; Procházková, G.; Šafařík, Ivo

    2013-01-01

    Roč. 56, č. 6 (2013), s. 456-461. ISSN 0266-8254 R&D Projects: GA MŠk(CZ) LD13023; GA MŠk(CZ) LD13021 Institutional support: RVO:67179843 Keywords : invert sugar formation * magnetic iron oxide microparticles * magnetic modification * magnetic separation * microwave-assisted synthesis * whole-cell biocatalyst * yeast cells Subject RIV: EI - Biotechnology ; Bionics Impact factor: 1.749, year: 2013

  5. Isolation and manipulation of living adherent cells by micromolded magnetic rafts

    Gach, Philip C.; Wang, Yuli; Phillips, Colleen; Sims, Christopher E.; Allbritton, Nancy L.

    2011-01-01

    A new strategy for magnetically manipulating and isolating adherent cells with extremely high post-collection purity and viability is reported. Micromolded magnetic elements (termed microrafts) were fabricated in an array format and used as culture surfaces and carriers for living, adherent cells. A poly(styrene-co-acrylic acid) polymer containing well dispersed magnetic nanoparticles was developed for creating the microstructures by molding. Nanoparticles of γFe2O3 at concentrations up to 1%...

  6. Characterization of Rat Hair Follicle Stem Cells Selected by Vario Magnetic Activated Cell Sorting System

    Hair follicle stem cells (HfSCs) play crucial roles in hair follicle morphogenesis and hair cycling. These stem cells are self-renewable and have the multi-lineage potential to generate epidermis, sebaceous glands, and hair follicle. The separation and identification of hair follicle stem cells are important for further research in stem cell biology. In this study, we report on the successful enrichment of rat hair follicle stem cells through vario magnetic activated cell sorting (Vario MACS) and the biological characteristics of the stem cells. We chose the HfSCs positive surface markers CD34, α6-integrin and the negative marker CD71 to design four isolation strategies: positive selection with single marker of CD34, positive selection with single marker of α6-integrin, CD71 depletion followed by CD34 positive selection, and CD71 depletion followed by α6-integrin positive selection. The results of flow cytometry analysis showed that all four strategies had ideal effects. Specifically, we conducted a series of researches on HfSCs characterized by their high level of CD34, termed CD34bri cells, and low to undetectable expression of CD34, termed CD34dim cells. CD34bri cells had greater proliferative potential and higher colony-forming ability than CD34dim cells. Furthermore, CD34bri cells had some typical characteristics as progenitor cells, such as large nucleus, obvious nucleolus, large nuclear:cytoplasmic ratio and few cytoplasmic organelles. Our findings clearly demonstrated that HfSCs with high purity and viability could be successfully enriched with Vario MACS

  7. Application of Cell Penetrating Peptide in Magnetic Resonance Imaging of Bone Marrow Mesenchymal Stem Cells

    Min LIU; You-Min GUO; Jun-Le YANG; Peng WANG; Lin-Yu ZHAO; Nian SHEN; Si-Cen WANG; Xiao-Juan GUO; Qi-Fei WU

    2006-01-01

    Tracking the distribution and differentiation of stem cells by high-resolution imaging techniques would have significant clinical and research implications. In this study, a model cell-penetrating peptide was used to carry gadolinium particles for magnetic resonance imaging (MRI) of mesenchymal stem cells (MSCs).MSCs were isolated from rat bone marrow and identified by osteogenic differentiation in vitro. The cellpenetrating peptide labeled with fluorescein-5-isothiocyanate (FITC) and gadolinium was synthesized by a solid-phase peptide synthesis method. Fluorescein imaging analysis confirmed that this new peptide could internalize into the cytoplasm and nucleus at room temperature, 4℃ and 37℃. Gadolinium were efficiently internalized into mesenchymal stem cells by the peptide in a time or concentration-dependent manner,resulting in intercellular shortening of longitudinal relaxation enhancements, which were obviously detected by 1.5 Tesla Magnetic Resonance Imaging. Cytotoxicity assay and flow cytometric analysis showed that the intercellular contrast medium incorporation did not affect cell viability at the tested concentrations. The in vitro experiment results suggested that the new constructed peptides could be a vector for tracking MSCs.

  8. Application of magnetic poly(styrene-glycidyl methacrylate) microspheres for immunomagnetic separation of bone marrow cells

    Chung, T.-H.; Chang, J.-Y. [Department of Chemical Engineering, National Chung Cheng University, Chiayi 621, Taiwan (China); Lee, W.-C. [Department of Chemical Engineering, National Chung Cheng University, Chiayi 621, Taiwan (China)], E-mail: chmwcl@ccu.edu.tw

    2009-05-15

    Surface-functionalized magnetic poly(styrene-glycidyl methacrylate) (PS-GMA) microspheres were prepared and coupled with Sca-1 antibody for cell selection from murine bone marrow mononuclear cells (MNCs). Biotinylated Sca-1 antibody could be directly coupled to avidin-bound magnetic microspheres. Alternatively, oxidized goat anti-mouse antibody was covalently bound onto the amino group-containing magnetic microspheres in a site-directed manner, and the resultant conjugate was coupled with non-modified Sca-1 antibody. Using the indirect antibody-bound magnetic microspheres, the purity of isolated Sca-1{sup +} cells increased with bead-to-cell ratio. Using a bead-to-cell ratio of 10 beads/cell, a purity of 85% Sca-1{sup +} cells corresponding to a 17-fold enrichment was achieved.

  9. Application of magnetic poly(styrene-glycidyl methacrylate) microspheres for immunomagnetic separation of bone marrow cells

    Surface-functionalized magnetic poly(styrene-glycidyl methacrylate) (PS-GMA) microspheres were prepared and coupled with Sca-1 antibody for cell selection from murine bone marrow mononuclear cells (MNCs). Biotinylated Sca-1 antibody could be directly coupled to avidin-bound magnetic microspheres. Alternatively, oxidized goat anti-mouse antibody was covalently bound onto the amino group-containing magnetic microspheres in a site-directed manner, and the resultant conjugate was coupled with non-modified Sca-1 antibody. Using the indirect antibody-bound magnetic microspheres, the purity of isolated Sca-1+ cells increased with bead-to-cell ratio. Using a bead-to-cell ratio of 10 beads/cell, a purity of 85% Sca-1+ cells corresponding to a 17-fold enrichment was achieved.

  10. Application of magnetic poly(styrene-glycidyl methacrylate) microspheres for immunomagnetic separation of bone marrow cells

    Chung, Ting-Hao; Chang, Jing-Yi; Lee, Wen-Chien

    2009-05-01

    Surface-functionalized magnetic poly(styrene-glycidyl methacrylate) (PS-GMA) microspheres were prepared and coupled with Sca-1 antibody for cell selection from murine bone marrow mononuclear cells (MNCs). Biotinylated Sca-1 antibody could be directly coupled to avidin-bound magnetic microspheres. Alternatively, oxidized goat anti-mouse antibody was covalently bound onto the amino group-containing magnetic microspheres in a site-directed manner, and the resultant conjugate was coupled with non-modified Sca-1 antibody. Using the indirect antibody-bound magnetic microspheres, the purity of isolated Sca-1 + cells increased with bead-to-cell ratio. Using a bead-to-cell ratio of 10 beads/cell, a purity of 85% Sca-1 + cells corresponding to a 17-fold enrichment was achieved.

  11. Response of animal and vegetative cells to the effect of a typical magnetic storm

    Talikina, M. G.; Izyumov, Yu. G.; Krylov, V. V.

    2013-12-01

    Experimentally reproduced fluctuations of a low-frequency magnetic field in a nanotesla range (magnetic storm) affect the mitosis of animals and vegetative cells. Action of this factor during twenty four hours leads to a significant increase in the proliferative activity of embryo cells in roach ( Rutilus rutilus L.) and meristem cells of onion rootlets ( Allium cepa). The clastogenic effect statistically confirmed only in the Allium test seems to reflect the species specificity of the response and higher sensitivity of the cell association of the onion meristem to magnetic storm.

  12. Detection of circulating tumor cells using targeted surface-enhanced Raman scattering nanoparticles and magnetic enrichment

    Shi, Wei; Paproski, Robert J.; Moore, Ronald; Zemp, Roger

    2014-05-01

    While more than 90% of cancer deaths are due to metastases, our ability to detect circulating tumor cells (CTCs) is limited by low numbers of these cells in the blood and factors confounding specificity of detection. We propose a magnetic enrichment and detection technique for detecting CTCs with high specificity. We targeted both magnetic and surface-enhanced Raman scattering (SERS) nanoparticles to cancer cells. Only cells that are dual-labeled with both kinds of nanoparticles demonstrate an increasing SERS signal over time due to magnetic trapping.

  13. Cell death induced by application of time-varying magnetic fields on nanoparticle-loaded dendritic cells

    Marcos-Campos, I; Torres, T E; Marquina, C; Tres, A; Ibarra, M R; Goya, G F

    2010-01-01

    Aim: To assess the capability of monocyte-derived dendritic cells (DCs) to take Fe3O4 magnetic nanoparticles (MNPs), keeping their viability. To provoke cell death on these MNPs-loaded DCs using an external alternating magnetic field (AMF). Material & methods: Peripheral blood mononuclear cells were isolated from normal blood and platelets removed by centrifugation. Immunoselected CD14+ cells were cultured for 5 days, and the resulting cell phenotype was determined against several markers using flow cytometry. Co-cultures of DCs and MNPs were done overnight. The amount of Fe3O4 nanoparticles incorporated by DCs was quantified by magnetization measurements. MNPs-loaded DCs were exposed to AMF for 30 min and then cell viability was measured using trypan blue and FACS (annexin-propidium iodide) protocols. Morphological changes were investigated using scanning electron microscopy. Results: No significant decrease in cell viability of MNP/loaded DCs was observed up to five days, as compared against control sam...

  14. Imaging of magnetic microfield distortions allows sensitive single-cell detection.

    Lindquist, Randall L; Papazoglou, Sebastian; Scharlach, Constantin; Waiczies, Helmar; Schnorr, Jörg; Taupitz, Matthias; Hamm, Bernd; Schellenberger, Eyk

    2013-01-01

    Cell tracking with magnetic resonance imaging (MRI) is mostly performed using superparamagnetic iron oxide (SPIO) nanoparticle-labeled cells. However, negative contrast in T2*-weighted imaging is inherently problematic as a homogeneous background signal is required to visualize the negative signal. In a magnetic field, SPIO-labeled cells develop their own magnetization, distorting the main field. We show here a method to visualize these distortions and use them to identify single cells with increased sensitivity and certainty compared to T2* images. We labeled HeLa cells with SPIOs, suspended labeled cells in agarose to make phantoms, and performed high-resolution gradient-echo MRI. Phase images were processed to enhance the visibility of single cells. To quantify SPIO content, we generated a map of frequency differences. MRI of cell phantoms showed that single cells could be detected at concentrations ranging from 200 to 10,000 cells mL(-1). Postprocessing of the magnetic resonance phase images reveals characteristic microfield distortions, increasing dramatically the sensitivity of cell recognition, compared to unprocessed T2* images. Calculating frequency shifts and comparing microfield distortions to simulations permit estimation of the nanoparticle load of single cells. We expect the ability to detect and quantify the iron load of single cells to prove useful in studies of cell trafficking, especially in rare cell populations. PMID:23415396

  15. Static Magnetic Field Attenuates Lipopolysaccharide-Induced Inflammation in Pulp Cells by Affecting Cell Membrane Stability

    Sung-Chih Hsieh

    2015-01-01

    Full Text Available One of the causes of dental pulpitis is lipopolysaccharide- (LPS- induced inflammatory response. Following pulp tissue inflammation, odontoblasts, dental pulp cells (DPCs, and dental pulp stem cells (DPSCs will activate and repair damaged tissue to maintain homeostasis. However, when LPS infection is too serious, dental repair is impossible and disease may progress to irreversible pulpitis. Therefore, the aim of this study was to examine whether static magnetic field (SMF can attenuate inflammatory response of dental pulp cells challenged with LPS. In methodology, dental pulp cells were isolated from extracted teeth. The population of DPSCs in the cultured DPCs was identified by phenotypes and multilineage differentiation. The effects of 0.4 T SMF on DPCs were observed through MTT assay and fluorescent anisotropy assay. Our results showed that the SMF exposure had no effect on surface markers or multilineage differentiation capability. However, SMF exposure increases cell viability by 15%. In addition, SMF increased cell membrane rigidity which is directly related to higher fluorescent anisotropy. In the LPS-challenged condition, DPCs treated with SMF demonstrated a higher tolerance to LPS-induced inflammatory response when compared to untreated controls. According to these results, we suggest that 0.4 T SMF attenuates LPS-induced inflammatory response to DPCs by changing cell membrane stability.

  16. Process optimization and biocompatibility of cell carriers suitable for automated magnetic manipulation.

    Krejci, I; Piana, C.; Howitz, S.; Wegener, T; Fiedler, S.; ZWANZIG, M.; Schmitt, D.; Daum, N; Meier, K.; Lehr, C. M.; Batista, U; Zemljic, S; Messerschmidt, J.; Franzke, J; M. Wirth

    2012-01-01

    There is increasing demand for automated cell reprogramming in the fields of cell biology, biotechnology and the biomedical sciences. Microfluidic-based platforms that provide unattended manipulation of adherent cells promise to be an appropriate basis for cell manipulation. In this study we developed a magnetically driven cell carrier to serve as a vehicle within an in vitro environment. To elucidate the impact of the carrier on cells, biocompatibility was estimated using the human adenocarc...

  17. External magnetic field effect on bifacial silicon solar cell''s electric power and conversion efficiencyExternal magnetic field effect on bifacial silicon solar cell''s electric power and conversion efficiency

    ZERBO, ISSA; ZOUNGRANA, MARTIAL; SOURABIE, IDRISSA; Ouedraogo, Adama; ZOUMA, BERNARD; BATHIEBO, DIEUDONNE JOSEPH

    2015-01-01

    This article presents a modelling study of external magnetic field effect on a bifacial silicon solar cell's electric power and conversion efficiency. After the resolution of the magnetotransport equation and continuity equation of excess minority carriers, we calculate the photocurrent density and the photovoltage and then we deduce the solar cell's electric power before discussing the influence of the magnetic field on those electrical parameters. Using the electric power curves...

  18. Particle-in-cell simulations of plasma opening switch with external magnetic field

    Fully electromagnetic particle-in-cell simulations are performed to study the effects of an external magnetic field on coaxial plasma opening switch (POS). The simulation results show that POS opening performance can be significantly improved only when external longitudinal magnetic field coils are placed at the cathode side, and an additional azimuthal magnetic field is effective whether the central electrode is of positive or negative polarity. Voltage multiplication coefficient K rises with the additional magnetic field increasing till the electron current is completely magnetically insulated during the opening of POS

  19. Magnetic field effects in dye-sensitized solar cells controlled by different cell architecture

    Klein, M.; Pankiewicz, R.; Zalas, M.; Stampor, W.

    2016-01-01

    The charge recombination and exciton dissociation are generally recognized as the basic electronic processes limiting the efficiency of photovoltaic devices. In this work, we propose a detailed mechanism of photocurrent generation in dye-sensitized solar cells (DSSCs) examined by magnetic field effect (MFE) technique. Here we demonstrate that the magnitude of the MFE on photocurrent in DSSCs can be controlled by the radius and spin coherence time of electron-hole (e-h) pairs which are experimentally modified by the photoanode morphology (TiO2 nanoparticles or nanotubes) and the electronic orbital structure of various dye molecules (ruthenium N719, dinuclear ruthenium B1 and fully organic squaraine SQ2 dyes). The observed MFE is attributed to magnetic-field-induced spin-mixing of (e-h) pairs according to the Δg mechanism. PMID:27440452

  20. Magnetic field effects in dye-sensitized solar cells controlled by different cell architecture

    Klein, M.; Pankiewicz, R.; Zalas, M.; Stampor, W.

    2016-07-01

    The charge recombination and exciton dissociation are generally recognized as the basic electronic processes limiting the efficiency of photovoltaic devices. In this work, we propose a detailed mechanism of photocurrent generation in dye-sensitized solar cells (DSSCs) examined by magnetic field effect (MFE) technique. Here we demonstrate that the magnitude of the MFE on photocurrent in DSSCs can be controlled by the radius and spin coherence time of electron-hole (e-h) pairs which are experimentally modified by the photoanode morphology (TiO2 nanoparticles or nanotubes) and the electronic orbital structure of various dye molecules (ruthenium N719, dinuclear ruthenium B1 and fully organic squaraine SQ2 dyes). The observed MFE is attributed to magnetic-field-induced spin-mixing of (e-h) pairs according to the Δg mechanism.

  1. Magnetic field effects in dye-sensitized solar cells controlled by different cell architecture.

    Klein, M; Pankiewicz, R; Zalas, M; Stampor, W

    2016-01-01

    The charge recombination and exciton dissociation are generally recognized as the basic electronic processes limiting the efficiency of photovoltaic devices. In this work, we propose a detailed mechanism of photocurrent generation in dye-sensitized solar cells (DSSCs) examined by magnetic field effect (MFE) technique. Here we demonstrate that the magnitude of the MFE on photocurrent in DSSCs can be controlled by the radius and spin coherence time of electron-hole (e-h) pairs which are experimentally modified by the photoanode morphology (TiO2 nanoparticles or nanotubes) and the electronic orbital structure of various dye molecules (ruthenium N719, dinuclear ruthenium B1 and fully organic squaraine SQ2 dyes). The observed MFE is attributed to magnetic-field-induced spin-mixing of (e-h) pairs according to the Δg mechanism. PMID:27440452

  2. Effect of magnetic nanoparticles on apoptosis and cell cycle induced by wogonin in Raji cells

    Wang XM

    2012-02-01

    Full Text Available Lei Wang1,2,*, Haijun Zhang1,2,*, Baoan Chen1,2, Guohua Xia1,2, Shuai Wang1,2, Jian Cheng1,2, Zeye Shao1,2, Chong Gao1,2, Wen Bao1,2, Liang Tian1,2, Yanyan Ren1,2, Peipei Xu1,2, Xiaohui Cai1,2, Ran Liu1,2, Xuemei Wang3 1Department of Hematology and Oncology, Zhongda Hospital, Medical School, 2Faculty of Oncology, Medical School, 3State Key Laboratory of Bioelectronics (Chien-Shiung Wu Laboratory, Southeast University, Nanjing, China*These authors contributed equally to this workAbstract: Traditional Chinese medicine is gradually becoming a new source of anticancer drugs. One such example is wogonin, which is cytotoxic to various cancer cell lines in vitro. However, due to its low water solubility, wogonin is restricted to clinical administration. Recently, the application of drug-coated magnetic nanoparticles (MNPs to increase water solubility of the drug and to enhance its chemotherapeutic efficiency has attracted much attention. In this study, wogonin was conjugated with the drug delivery system of MNPs by mechanical absorption polymerization to fabricate wogonin-loaded MNPs. It was demonstrated that MNPs could strengthen wogonin-induced cell inhibition, apoptosis, and cell cycle arrest in Raji cells by methylthiazol tetrazolium assay, flow cytometer assay, and nuclear 4',6-diamidino-2-phenylindole staining. Furthermore, the molecular mechanisms of these phenomena were explored by western blot, in which the protein levels of caspase 8 and caspase 3 were increased significantly while those of survivin and cyclin E were decreased significantly in wogonin-MNPs group. These findings suggest that the combination of wogonin and MNPs provides a promising strategy for lymphoma therapy.Keywords: wogonin, magnetic nanoparticles, Raji cell, apoptosis, cell cycle, caspase 8, caspase 3, survivin, cyclin E

  3. Cell and membrane lipid analysis by proton magnetic resonance spectroscopy in five breast cancer cell lines.

    Le Moyec, L; Tatoud, R; Eugène, M; Gauvillé, C; Primot, I; Charlemagne, D; Calvo, F

    1992-10-01

    The lipid composition of five human breast cancer cell lines (MCF-7, T47D, ZR-75-1, SKBR3 and MDA-MB231) was assessed by proton magnetic resonance spectroscopy (MRS) in whole cells and membrane-enriched fractions. The proportions of the three main lipid resonances in 1D spectra were different for each cell line. These resonances included mobile methyl and methylene functions from fatty acids of triglycerides and phospholipids and N-trimethyl from choline of phospholipids. T47D and ZR-75-1 cells presented a high methylene/methyl ratio (6.02 +/- 0.35 and 6.28 +/- 0.90). This ratio was significantly lower for SKBR3, MCF-7 and MDA-MB231 cells (2.76 +/- 0.22, 2.27 +/- 0.57 and 1.39 +/- 0.39). The N-trimethyl/methyl ratio was high for MDA-MB231 and SKBR3 cells (1.38 +/- 0.54 and 0.86 +/- 0.32), but lower for MCF-7, T47D and ZR-75-1 cells (0.49 +/- 0.11, 0.16 +/- 0.07 and 0.07 +/- 0.03). 2D COSY spectra confirmed these different proportions in mobile lipids. From 1D spectra obtained on membrane preparations, T47D and ZR-75-1 were the only cell lines to retain a signal from mobile methylene functions. These differences might be related to the heterogeneity found for several parameters of these cells (tumorigenicity, growth rate, hormone receptors); an extended number of cases from fresh samples might enable clinical correlations. PMID:1329906

  4. Neural stem cells harvested from live brains by antibody-conjugated magnetic nanoparticles.

    Lui, C N P; Tsui, Y P; Ho, A S L; Shum, D K Y; Chan, Y S; Wu, C T; Li, H W; Tsang, S C Edman; Yung, K K L

    2013-11-18

    It stems from the magnetism: The extraction of stem/progenitor cells from the brain of live animals is possible using antibodies conjugated to magnetic nanoparticles (Ab-MNPs). The Ab-MNPs are introduced to a rat's brain with a superfine micro-syringe. The stem cells attach to the Ab-MNPs and are magnetically isolated and removed. They can develop into neurospheres and differentiate into different types of cells outside the subject body. The rat remains alive and healthy. PMID:24108547

  5. One Step Quick Detection of Cancer Cell Surface Marker by Integrated NiFe-based Magnetic Biosensing Cell Cultural Chip

    Chenchen Bao; Lei Chen; Tao Wang; Chong Lei; Furong Tian; Daxiang Cui; Yong Zhou

    2013-01-01

    RGD peptides has been used to detect cell surface integrin and direct clinical effective therapeutic drug selection. Herein we report that a quick one step detection of cell surface marker that was realized by a specially designed NiFe-based magnetic biosensing cell chip combined with functionalized magnetic nanoparti-cles. Magnetic nanoparticles with 20-30 nm in diameter were prepared by coprecipitation and modified with RGD-4C, and the resultant RGD-functionalized magnetic nanoparticles were used for targeting cancer cells cul-tured on the NiFe-based magnetic biosensing chip and distinguish the amount of cell surface receptor-integrin. Cell lines such as Calu3, Hela, A549, CaFbr, HEK293 and HUVEC exhibiting different integrin expression were chosen as test samples. Calu3, Hela, HEK293 and HUVEC cells were successfully identified. This approach has advantages in the qualitative screening test. Compared with traditional method, it is fast, sensitive, low cost, easy-operative, and needs very little human intervention. The novel method has great potential in applications such as fast clinical cell surface marker detection, and diagnosis of early cancer, and can be easily extended to other biomedical applications based on molecular recognition.

  6. Magnetic resonance imaging and cell-based neurorestorative therapy after brain injury

    Quan Jiang

    2016-01-01

    Restorative cell-based therapies for experimental brain injury, such as stroke and traumatic brain injury, substantially improve functional outcome. We discuss and review state of the art magnetic resonance im-aging methodologies and their applications related to cell-based treatment after brain injury. We focus on the potential of magnetic resonance imaging technique and its associated challenges to obtain useful new information related to cell migration, distribution, and quantitation, as well as vascular and neuronal remodeling in response to cell-based therapy after brain injury. The noninvasive nature of imaging might more readily help with translation of cell-based therapy from the laboratory to the clinic.

  7. Magnetic resonance imaging and cell-based neurorestorative therapy after brain injury

    Quan Jiang

    2016-01-01

    Full Text Available Restorative cell-based therapies for experimental brain injury, such as stroke and traumatic brain injury, substantially improve functional outcome. We discuss and review state of the art magnetic resonance imaging methodologies and their applications related to cell-based treatment after brain injury. We focus on the potential of magnetic resonance imaging technique and its associated challenges to obtain useful new information related to cell migration, distribution, and quantitation, as well as vascular and neuronal remodeling in response to cell-based therapy after brain injury. The noninvasive nature of imaging might more readily help with translation of cell-based therapy from the laboratory to the clinic.

  8. Quantification of the aggregation of magnetic nanoparticles with different polymeric coatings in cell culture medium

    Eberbeck, D; Kettering, M; Bergemann, C; Zirpel, P; Hilger, I; Trahms, L.

    2010-01-01

    Abstract The knowledge of the physico-chemical characteristics of magnetic nanoparticles (MNPs) is essential to enhance the efficacy of MNP-based therapeutic treatments (e.g. magnetic heating, magnetic drug targeting). According to the literature, the MNP uptake by cells may depend on the coating of MNPs, the surrounding medium as well as on the aggregation behaviour of the MNPs. Therefore, in this study, the aggregation behaviour of MNPs in various media was investigated. MNPs with differ...

  9. [Determination of the nucleic acids in pig embryonic kidney cells by magnetic cytaphoresis].

    Chikov, V M; Maksimova, E V

    1989-01-01

    Gallocyanine-chrome alum-stained pig embryonic kidney cells have paramagnetic properties. They move under the influence of gradient magnetic field (magnetophoresis). The velocity of magnetophoresis is proportional to the content of nucleic acids in cells. This allows to estimate the content of nucleic acids per cell dry weight by magnetophoresis and analytical centrifugation. PMID:2473104

  10. THE INFLUENCE OF MAGNETIC FIELDS ON INHIBITION OF MCF-7 CELL GROWTH BY TAMOXIFEN

    THE INFLUENCE OF MAGNETIC FIELDS ON INHIBITION OF MCF-7 CELL GROWTH BY TAMOXIFEN.Harland and Liburdy (1) reported that 1.2-uT, 60-Hz magnetic fields could significantly block the inhibitory action of pharmacological levels of tamoxifen (10-7 M) on the growth of MCF-7 human br...

  11. Studies of cell toxicity of complexes of magnetic fluids and biological macromolecules

    In this study, we performed a comparative investigation of the binding properties of two surface-coated (carboxymethyldextran/glucuronic acid), magnetite-based biocompatible magnetic fluids with different biological macromolecules (BSA, HSA, and LDL). We also investigated the in vitro toxicity of the complex formed between the magnetic fluid and the biological macromolecule in the neoplastic cell line J774-A

  12. Studies of cell toxicity of complexes of magnetic fluids and biological macromolecules

    Macaroff, Patrícia P.; Oliveira, Daniela M.; Ribeiro, Karina F.; Lacava, Zulmira G. M.; Lima, Emília C. D.; Morais, Paulo C.; Tedesco, Antonio C.

    2005-05-01

    In this study, we performed a comparative investigation of the binding properties of two surface-coated (carboxymethyldextran/glucuronic acid), magnetite-based biocompatible magnetic fluids with different biological macromolecules (BSA, HSA, and LDL). We also investigated the in vitro toxicity of the complex formed between the magnetic fluid and the biological macromolecule in the neoplastic cell line J774-A.

  13. Linear patterning of magnetically labeled Dictyostelium cells to display confined development

    Frasca, Guillaume; Raynaud, Franck; Bacri, Jean-Claude; Gazeau, Florence; Wilhelm, Claire [Laboratoire Matiere et Systemes Complexes (MSC), UMR 7057 CNRS et Universite Paris-Diderot, Paris (France)], E-mail: claire.wilhelm@univ-paris-diderot.fr

    2008-05-21

    In severe nutriment conditions, the social amoeba Dictyostelium discoideum enters a particular life cycle where it forms multicellular patterns to achieve aggregation. Extensively observed from an initial dispersed state, its developmental program can usefully be studied from a confined population to implement theoretical developments regarding biological self-organization. The challenge is then to form a cell assembly of well-defined geometrical dimensions without hindering cell behavior. To achieve this goal, we imposed transient constraints by applying temporary external magnetic gradients to trap magnetically labeled cells. Deposits of various numbers of cells were geometrically characterized for different magnetic exposure conditions. We demonstrated that the cell deposit was organized as a three-dimensional (3D) structure by both stacking layers of cells and extending these layers in the substrate plane. This structure evolves during the aggregation phase, forming periodic aggregative centers along the linear initial pattern.

  14. Microwave-synthesized magnetic chitosan microparticles for the immobilization of yeast cells.

    Safarik, Ivo; Pospiskova, Kristyna; Maderova, Zdenka; Baldikova, Eva; Horska, Katerina; Safarikova, Mirka

    2015-01-01

    An extremely simple procedure has been developed for the immobilization of Saccharomyces cerevisiae cells on magnetic chitosan microparticles. The magnetic carrier was prepared using an inexpensive, simple, rapid, one-pot process, based on the microwave irradiation of chitosan and ferrous sulphate at high pH. Immobilized yeast cells have been used for sucrose hydrolysis, hydrogen peroxide decomposition and the adsorption of selected dyes. PMID:24753015

  15. Can Lucifer Yellow Indicate Correct Permeability of Biological Cell Membrane under An Electric and Magnetic Field?

    Tahereh Pourmirjafari Firoozabadi

    2015-01-01

    Full Text Available The effect of external magnetic and electric fields, in the range of electroporation and magnetoporation, on Lucifer Yellow (LY fluorescence in the absence of cells is studied. Electric-field-induced quenching and magnetic field-induced increase are observed for fluorescence intensity of LY. Regard to the fact that the variation of field-induced fluorescence, even in the absence of cells, can be observed, the application of LY, as a marker, is debatable in electroporation and magnetoporation techniques.

  16. Can Lucifer Yellow Indicate Correct Permeability of Biological Cell Membrane under An Electric and Magnetic Field?

    Tahereh Pourmirjafari Firoozabadi; Zeinab Shankayi; Azam Izadi; Seyed Mohammad Pourmirjafari Firoozabadi

    2015-01-01

    The effect of external magnetic and electric fields, in the range of electroporation and magnetoporation, on Lucifer Yellow (LY) fluorescence in the absence of cells is studied. Electric-field-induced quenching and magnetic field-induced increase are observed for fluorescence intensity of LY. Regard to the fact that the variation of field-induced fluorescence, even in the absence of cells, can be observed, the application of LY, as a marker, is debatable in electroporation and magnetoporation...

  17. Can Lucifer Yellow Indicate Correct Permeability of Biological Cell Membrane under An Electric and Magnetic Field?

    Pourmirjafari Firoozabadi, Tahereh; Shankayi, Zeinab; Izadi, Azam; Pourmirjafari Firoozabadi, Seyed Mohammad

    2015-01-01

    The effect of external magnetic and electric fields, in the range of electroporation and magnetoporation, on Lucifer Yellow (LY) fluorescence in the absence of cells is studied. Electric-field-induced quenching and magnetic field-induced increase are observed for fluorescence intensity of LY. Regard to the fact that the variation of field-induced fluorescence, even in the absence of cells, can be observed, the application of LY, as a marker, is debatable in electroporation and magnetoporation techniques. PMID:25685747

  18. Flexible Programming of Cell-Free Protein Synthesis Using Magnetic Bead-Immobilized Plasmids

    Lee, Ka-Young; Lee, Kyung-Ho; Park, Ji-Woong; Kim, Dong-Myung

    2012-01-01

    The use of magnetic bead-immobilized DNA as movable template for cell-free protein synthesis has been investigated. Magnetic microbeads containing chemically conjugated plasmids were used to direct cell-free protein synthesis, so that protein generation could be readily programmed, reset and reprogrammed. Protein synthesis by using this approach could be ON/OFF-controlled through repeated addition and removal of the microbead-conjugated DNA and employed in sequential expression of different g...

  19. Magnetic trapping with simultaneous photoacoustic detection of molecularly targeted rare circulating tumor cells

    Wei, Chen-Wei; Xia, Jinjun; Pelivanov, Ivan M.; Hu, Xiaoge; Gao, Xiaohu; O'Donnell, Matthew

    2013-03-01

    Photoacoustic (PA) imaging has been widely used in molecular imaging to detect diseased cells by targeting them with nanoparticle-based contrast agents. However, the sensitivity and specificity are easily degraded because contrast agent signals can be masked by the background. Magnetomotive photoacoustic imaging uses a new type of multifunctional composite particle combining an optically absorptive gold nanorod core and magnetic nanospheres, which can potentially accumulate and concentrate targeted cells while simultaneously enhancing their specific contrast compared to background signals. In this study, HeLa cells molecularly targeted using nanocomposites with folic acid mimicking targeted rare circulating tumor cells (CTCs) were circulated at a 6 ml/min flow rate for trapping and imaging studies. Preliminary results show that the cells accumulate rapidly in the presence of an externally applied magnetic field produced by a dual magnet system. The sensitivity of the current system can reach up to 1 cell/ml in clear water. By manipulating the trapped cells magnetically, the specificity of detecting cells in highly absorptive ink solution can be enhanced with 16.98 dB background suppression by applying motion filtering on PA signals to remove unwanted background signals insensitive to the magnetic field. The results appear promising for future preclinical studies on a small animal model and ultimate clinical detection of rare CTCs in the vasculature.

  20. Sliced Magnetic Polyacrylamide Hydrogel with Cell-Adhesive Microarray Interface: A Novel Multicellular Spheroid Culturing Platform.

    Hu, Ke; Zhou, Naizhen; Li, Yang; Ma, Siyu; Guo, Zhaobin; Cao, Meng; Zhang, Qiying; Sun, Jianfei; Zhang, Tianzhu; Gu, Ning

    2016-06-22

    Cell-adhesive properties are of great significance to materials serving as extracellular matrix mimics. Appropriate cell-adhesive property of material interface can balance the cell-matrix interaction and cell-cell interaction and can promote cells to form 3D structures. Herein, a novel magnetic polyacrylamide (PAM) hydrogel fabricated via combining magnetostatic field induced magnetic nanoparticles assembly and hydrogel gelation was applied as a multicellular spheroids culturing platform. When cultured on the cell-adhesive microarray interface of sliced magnetic hydrogel, normal and tumor cells from different cell lines could rapidly form multicellular spheroids spontaneously. Furthermore, cells which could only form loose cell aggregates in a classic 3D cell culture model (such as hanging drop system) were able to be promoted to form multicellular spheroids on this platform. In the light of its simplicity in fabricating as well as its effectiveness in promoting formation of multicellular spheroids which was considered as a prevailing tool in the study of the microenvironmental regulation of tumor cell physiology and therapeutic problems, this composite material holds promise in anticancer drugs or hyperthermia therapy evaluation in vitro in the future. PMID:27258682

  1. Geometrically pinned magnetic domain wall for multi-bit per cell storage memory

    Bahri, M. Al; Sbiaa, R.

    2016-06-01

    Spintronic devices currently rely on magnetic switching or controlled motion of domain walls (DWs) by an external magnetic field or a spin-polarized current. Controlling the position of DW is essential for defining the state/information in a magnetic memory. During the process of nanowire fabrication, creating an off-set of two parts of the device could help to pin DW at a precise position. Micromagnetic simulation conducted on in-plane magnetic anisotropy materials shows the effectiveness of the proposed design for pinning DW at the nanoconstriction region. The critical current for moving DW from one state to the other is strongly dependent on nanoconstricted region (width and length) and the magnetic properties of the material. The DW speed which is essential for fast writing of the data could reach values in the range of hundreds m/s. Furthermore, evidence of multi-bit per cell memory is demonstrated via a magnetic nanowire with more than one constriction.

  2. Particle-In-Cell Simulations of the Solar Wind Interaction with Lunar Crustal Magnetic Anomalies: Magnetic Cusp Regions

    Poppe, A. R.; Halekas, J. S.; Delory, G. T.; Farrell, W. M.

    2012-01-01

    As the solar wind is incident upon the lunar surface, it will occasionally encounter lunar crustal remanent magnetic fields. These magnetic fields are small-scale, highly non-dipolar, have strengths up to hundreds of nanotesla, and typically interact with the solar wind in a kinetic fashion. Simulations, theoretical analyses, and spacecraft observations have shown that crustal fields can reflect solar wind protons via a combination of magnetic and electrostatic reflection; however, analyses of surface properties have suggested that protons may still access the lunar surface in the cusp regions of crustal magnetic fields. In this first report from a planned series of studies, we use a 1 1/2-dimensional, electrostatic particle-in-cell code to model the self-consistent interaction between the solar wind, the cusp regions of lunar crustal remanent magnetic fields, and the lunar surface. We describe the self-consistent electrostatic environment within crustal cusp regions and discuss the implications of this work for the role that crustal fields may play regulating space weathering of the lunar surface via proton bombardment.

  3. Intracellular Delivery by Shape Anisotropic Magnetic Particle-Induced Cell Membrane Cuts.

    Lin, Ming-Yu; Wu, Yi-Chien; Lee, Ji-Ann; Tung, Kuan-Wen; Zhou, Jessica; Teitell, Michael A; Yeh, J Andrew; Chiou, Pei Yu

    2016-08-01

    Introducing functional macromolecules into a variety of living cells is challenging but important for biology research and cell-based therapies. We report a novel cell delivery platform based on rotating shape anisotropic magnetic particles (SAMPs), which make very small cuts on cell membranes for macromolecule delivery with high efficiency and high survivability. SAMP delivery is performed by placing commercially available nickel powder onto cells grown in standard cell culture dishes. Application of a uniform magnetic field causes the magnetic particles to rotate because of mechanical torques induced by shape anisotropic magnetization. Cells touching these rotating particles are nicked, which generates transient membrane pores that enable the delivery of macromolecules into the cytosol of cells. Calcein dye, 3 and 40 kDa dextran polymers, a green fluorescence protein (GFP) plasmid, siRNA, and an enzyme (β-lactamase) were successfully delivered into HeLa cells, primary normal human dermal fibroblasts (NHDFs), and mouse cortical neurons that can be difficult to transfect. The SAMP approach offers several advantages, including easy implementation, low cost, high throughput, and efficient delivery of a broad range of macromolecules. Collectively, SAMP delivery has great potential for a broad range of academic and industrial applications. PMID:26882924

  4. Enhanced reduction in cell viability by hyperthermia induced by magnetic nanoparticles

    Héctor L Rodríguez-Luccioni

    2011-02-01

    Full Text Available Héctor L Rodríguez-Luccioni, Magda Latorre-Esteves, Janet Méndez-Vega, Orlando Soto, Ana R Rodríguez, Carlos Rinaldi, Madeline Torres-LugoDepartment of Chemical Engineering, University of Puerto Rico, Mayagüez 00681, Puerto RicoAbstract: Colloidal suspensions of iron oxide magnetic nanoparticles are known to dissipate energy when exposed to an oscillating magnetic field. Such energy dissipation can be employed to locally raise temperature inside a tumor between 41°C and 45°C (hyperthermia to promote cell death, a treatment known as magnetic fluid hyperthermia (MFH. This work seeks to quantify differences between MFH and hot-water hyperthermia (HWH in terms of reduction in cell viability using two cancer cell culture models, Caco-2 (human epithelial colorectal adenocarcinoma and MCF-7 (human breast cancer. Magnetite nanoparticles were synthesized via the co-precipitation method and functionalized with adsorbed carboxymethyl dextran. Cytotoxicity studies indicated that in the absence of an oscillating magnetic field, cell viability was not affected at concentrations of up to 0.6 mg iron oxide/mL. MFH resulted in a significant decrease in cell viability when exposed to a magnetic field for 120 minutes and allowed to rest for 48 hours, compared with similar field applications, but with shorter resting time. The results presented here suggest that MFH most likely induces apoptosis in both cell types. When compared with HWH, MFH produced a significant reduction in cell viability, and these effects appear to be cell-type related.Keywords: magnetic fluid hyperthermia, carboxymethyl dextran magnetite, cell death, apoptosis

  5. Effects of AC magnetic field and carboxymethyldextran-coated magnetite nanoparticles on mice peritoneal cells

    A portable apparatus was developed to perform magnetohyperthermia (MHT) assays. In order to investigate its efficiency on cell lysis, biological effects of the AC magnetic field exposure after carboxymethyldextran-coated magnetite-nanoparticles (CMDC) treatment were investigated. Phagocyte capacity, cell viability, and morphology data evidenced that the CMDC sample and the apparatus are useful to further investigate MHT in cancer therapy

  6. ORIENTATION REQUIREMENT TO DETECT MAGNETIC FIELD-INDUCTED ALTERATION OF GAP JUNCTION COMMUNICATION IN EPITHELIAL CELLS

    ORIENTATION REQUIREMENT TO DETECT MAGNETIC FIELD-INDUCED ALTERATION OF GAP JUNCTION COMMUNICATION IN EPITHELIAL CELLS. OBJECTIVE: We have shown that functional gap junction communication as measured by Lucifer yellow dye transfer (DT) in Clone-9 rat liver epithelial cells, c...

  7. Effects of AC magnetic field and carboxymethyldextran-coated magnetite nanoparticles on mice peritoneal cells

    Araujo Guedes, Maria Helena [Depto de Genetica e Morfologia, Instituto de Ciencias Biologicas, Universidade de Brasilia, 70910-900 Brasilia-DF (Brazil); Sadeghiani, Neda [Depto de Genetica e Morfologia, Instituto de Ciencias Biologicas, Universidade de Brasilia, 70910-900 Brasilia-DF (Brazil); Lima Guedes Peixoto, Danielle [Depto de Genetica e Morfologia, Instituto de Ciencias Biologicas, Universidade de Brasilia, 70910-900 Brasilia-DF (Brazil); Poubel Coelho, Julia [Depto de Genetica e Morfologia, Instituto de Ciencias Biologicas, Universidade de Brasilia, 70910-900 Brasilia-DF (Brazil); Santos Barbosa, Luzirlane [Depto de Genetica e Morfologia, Instituto de Ciencias Biologicas, Universidade de Brasilia, 70910-900 Brasilia-DF (Brazil); Bentes Azevedo, Ricardo [Depto de Genetica e Morfologia, Instituto de Ciencias Biologicas, Universidade de Brasilia, 70910-900 Brasilia-DF (Brazil); Kueckelhaus, Selma [Depto de Genetica e Morfologia, Instituto de Ciencias Biologicas, Universidade de Brasilia, 70910-900 Brasilia-DF (Brazil); Faculdade de Medicina, Universidade de Brasilia, Area de Morfologia, 70910-900 Brasilia-DF (Brazil); Silva, Maria de Fatima da [Nucleo de Fisica Aplicada, Instituto de Fisica, Universidade de Brasilia, 70919-970 Brasilia-DF (Brazil); Morais, Paulo Cesar [Nucleo de Fisica Aplicada, Instituto de Fisica, Universidade de Brasilia, 70919-970 Brasilia-DF (Brazil); Guerrero Marques Lacava, Zulmira [Depto de Genetica e Morfologia, Instituto de Ciencias Biologicas, Universidade de Brasilia, 70910-900 Brasilia-DF (Brazil)]. E-mail: zulmira@unb.br

    2005-05-15

    A portable apparatus was developed to perform magnetohyperthermia (MHT) assays. In order to investigate its efficiency on cell lysis, biological effects of the AC magnetic field exposure after carboxymethyldextran-coated magnetite-nanoparticles (CMDC) treatment were investigated. Phagocyte capacity, cell viability, and morphology data evidenced that the CMDC sample and the apparatus are useful to further investigate MHT in cancer therapy.

  8. Cobalt zinc ferrite nanoparticles – a suitable tool for magnetic cell labeling

    Jendelová, Pavla; Novotná, Božena; Turnovcová, Karolína; Žvátora, Pavel; Veverka, Miroslav; Bagryantseva, Yana; Herynek, V.; Syková, Eva

    Leipzig : Fraunhofer Institute for Cell Therapy and Immunology, 2013. PP-137. [World Conference on Regenerative Medicine 2013 /WCRM 2013/. 23.10.2013-25.10.2013, Leipzig] R&D Projects: GA ČR(CZ) GAP304/12/1370; GA ČR GAP204/10/0035 Institutional support: RVO:68378271 ; RVO:68378041 Keywords : cobalt-zinc ferrite * cell labeling * magnetic resonance imaging * genotoxicity Subject RIV: FJ - Surgery incl. Transplants http://wcrm.future-science-group.com/pdfs/PP-137.pdf#search=%22magnetic%20cell%22

  9. Increasing the sensitivity for stem cell monitoring in system-function based magnetic particle imaging

    Them, Kolja; Salamon, J.; Szwargulski, P.; Sequeira, S.; Kaul, M. G.; Lange, C.; Ittrich, H.; Knopp, Tobias

    2016-05-01

    The use of superparamagnetic iron oxide nanoparticles (SPIONs) has provided new possibilities in biophysics and biomedical imaging technologies. The magnetization dynamics of SPIONs, which can be influenced by the environment, are of central interest. In this work, different biological SPION environments are used to investigate three different calibration methods for stem cell monitoring in magnetic particle imaging. It is shown that calibrating using SPIONs immobilized via agarose gel or intracellular uptake results in superior stem cell image quality compared to mobile SPIONs in saline. This superior image quality enables more sensitive localization and identification of a significantly smaller number of magnetically labeled stem cells. The results are important for cell tracking and monitoring of future SPION based therapies such as hyperthermia based cancer therapies, targeted drug delivery, or tissue regeneration approaches where it is crucial to image a sufficiently small number of SPIONs interacting with biological matter.

  10. Moissanite anvil cell design for giga-pascal nuclear magnetic resonance

    A new design of a non-magnetic high-pressure anvil cell for nuclear magnetic resonance (NMR) experiments at Giga-Pascal pressures is presented, which uses a micro-coil inside the pressurized region for high-sensitivity NMR. The comparably small cell has a length of 22 mm and a diameter of 18 mm, so it can be used with most NMR magnets. The performance of the cell is demonstrated with external-force vs. internal-pressure experiments, and the cell is shown to perform well at pressures up to 23.5 GPa using 800 μm 6H-SiC large cone Boehler-type anvils. 1H, 23Na, 27Al, 69Ga, and 71Ga NMR test measurements are presented, which show a resolution of better than 4.5 ppm, and an almost maximum possible signal-to-noise ratio

  11. Moissanite anvil cell design for giga-pascal nuclear magnetic resonance

    Meier, Thomas; Herzig, Tobias; Haase, Jürgen

    2014-04-01

    A new design of a non-magnetic high-pressure anvil cell for nuclear magnetic resonance (NMR) experiments at Giga-Pascal pressures is presented, which uses a micro-coil inside the pressurized region for high-sensitivity NMR. The comparably small cell has a length of 22 mm and a diameter of 18 mm, so it can be used with most NMR magnets. The performance of the cell is demonstrated with external-force vs. internal-pressure experiments, and the cell is shown to perform well at pressures up to 23.5 GPa using 800 μm 6H-SiC large cone Boehler-type anvils. 1H, 23Na, 27Al, 69Ga, and 71Ga NMR test measurements are presented, which show a resolution of better than 4.5 ppm, and an almost maximum possible signal-to-noise ratio.

  12. Three-dimensional magnetic focusing of particles and cells in ferrofluid flow through a straight microchannel

    Focusing particles and cells into a tight stream is often required in order for continuous flow detection, counting and sorting. So far a variety of particle focusing methods have been developed in microfluidic devices, among which magnetic focusing is still relatively new. We develop in this work an approach to embedding symmetrically two repulsive permanent magnets about a straight rectangular microchannel in a PDMS-based microfluidic device. The closest distance between the magnets is limited only by the sizes of the embedded and holder magnets involved in the fabrication process. The developed device is used to implement and investigate the three-dimensional magnetic focusing of polystyrene particles in ferrofluid microflow with both the top- and side-view visualizations. The effects of flow speed and particle size on the particle focusing effectiveness are studied. The developed device is also applied to magnetically focus yeast cells in ferrofluid, which proves to be biocompatible as verified by a cell viability test. In addition, an analytical model is developed and found to be able to predict the experimentally observed particle and cell focusing behaviors with reasonable agreement. (paper)

  13. A magnetic nanoparticle-based multiple-gene delivery system for transfection of porcine kidney cells.

    Yan Wang

    Full Text Available Superparamagnetic nanoparticles are promising candidates for gene delivery into mammalian somatic cells and may be useful for reproductive cloning using the somatic cell nuclear transfer technique. However, limited investigations of their potential applications in animal genetics and breeding, particularly multiple-gene delivery by magnetofection, have been performed. Here, we developed a stable, targetable and convenient system for delivering multiple genes into the nuclei of porcine somatic cells using magnetic Fe3O4 nanoparticles as gene carriers. After surface modification by polyethylenimine, the spherical magnetic Fe3O4 nanoparticles showed strong binding affinity for DNA plasmids expressing the genes encoding a green (DNAGFP or red (DNADsRed fluorescent protein. At weight ratios of DNAGFP or DNADsRed to magnetic nanoparticles lower than or equal to 10∶1 or 5∶1, respectively, the DNA molecules were completely bound by the magnetic nanoparticles. Atomic force microscopy analyses confirmed binding of the spherical magnetic nanoparticles to stretched DNA strands up to several hundred nanometers in length. As a result, stable and efficient co-expression of GFP and DsRed in porcine kidney PK-15 cells was achieved by magnetofection. The results presented here demonstrate the potential application of magnetic nanoparticles as an attractive delivery system for animal genetics and breeding studies.

  14. Biosorption of mercury on magnetically modified yeast cells

    Yavuz, H.; Denizli, A.; Gungunes, H.; Šafaříková, Miroslava; Šafařík, Ivo

    2006-01-01

    Roč. 52, - (2006), s. 253-260. ISSN 1383-5866 R&D Projects: GA MŠk(CZ) OC 108 Institutional research plan: CEZ:AV0Z60870520 Keywords : mercury removal * magnetic biosorbents * yeast Subject RIV: EI - Biotechnology ; Bionics Impact factor: 2.497, year: 2006

  15. Mechanical anisotropy and adaptation of metastatic cells probed by magnetic microbeads

    Zhang, Zhipeng; Shi, Yanhui; Jhiang, Sissy M.; Menq, Chia-Hsiang

    2010-02-01

    Metastatic cells have the ability to break through the basal lamina, enter the blood vessels, circulate through the vasculature, exit at distant sites, and form secondary tumors. This multi-step process, therefore, clearly indicates the inherent ability of metastatic cells to sense, process, and adapt to the mechanical forces in different surrounding environments. We describe a magnetic probing device that is useful in characterizing the mechanical properties of cells along arbitrary two-dimensional directions. Magnetic force, with the advantages of biocompatibility and specificity, was produced by magnetic poles placed in an octupole configuration and applied to fibronectin-coated magnetic microbeads attached on cell membrane. Cell deformation in response to the applied force was then recorded through the displacement of the microbeads. The motion of the beads was measured by computer processing the video images acquired by a high-speed CMOS camera. Rotating force vectors with constant magnitude while pointing to directions of all 360 degrees were applied to study the mechanical anisotropy of metastatic breast cancer cells MDA-MB-231. The temporal changes in magnitude and directionality of the cellular responses were then analyzed to investigate the cellular adaptation to force stimulation. This probing technology thus has the potential to provide us a better understanding of the mechano-signatures of cells.

  16. Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability

    Palmer, A; Silevitch, D M; Feng, Yejun; Wang, Y; Jaramillo, R.; Banerjee, A.; Ren, Y.; Rosenbaum, T. F.

    2015-09-01

    We discuss techniques for performing continuous measurements across a wide range of pressure–field–temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal.

  17. Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability

    Palmer, A.; Silevitch, D. M.; Feng, Yejun; Wang, Yishu; Jaramillo, R.; Banerjee, A.; Ren, Y.; Rosenbaum, T. F.

    2015-09-01

    We discuss techniques for performing continuous measurements across a wide range of pressure-field-temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal.

  18. Proton nuclear magnetic resonance of intact friend leukemia cells: phosphorylcholine increase during differentiation

    Proton nuclear magnetic resonance of intact Friend leukemia cells was used to analyze their erythroid-like differentiation. The technique, which requires only 108 to 109 cells and approximately 2 minutes for acquisition of each spectrum, demonstrated the occurrence of many signal changes during differentiation. With cell extracts, 64 signals were assigned to 12 amino acids and 19 other intermediary metabolites, and a dramatic signal change was attributed to a fourfrease in cytoplasmic phosphorylcholines

  19. Microfluidic sorting and multimodal typing of cancer cells in self-assembled magnetic arrays

    Saliba, Antoine-Emmanuel; Saias, Laure; Psychari, Eleni; Minc, Nicolas; Simon, Damien; Bidard, François-Clément; Mathiot, Claire; Pierga, Jean-Yves; Fraisier, Vincent; Salamero, Jean; Saada, Véronique; Farace, Françoise; Vielh, Philippe; Malaquin, Laurent; Viovy, Jean-Louis

    2010-01-01

    We propose a unique method for cell sorting, “Ephesia,” using columns of biofunctionalized superparamagnetic beads self-assembled in a microfluidic channel onto an array of magnetic traps prepared by microcontact printing. It combines the advantages of microfluidic cell sorting, notably the application of a well controlled, flow-activated interaction between cells and beads, and those of immunomagnetic sorting, notably the use of batch-prepared, well characterized antibody-bearing beads. On c...

  20. Magnetic Bionanoparticle Enhances Homing of Endothelial Progenitor Cells in Mouse Hindlimb Ischemia

    Kang, Hyun-Jae; Kim, Ju-Young; Lee, Ho-Jae; Kim, Keum-Hyun; Kim, Tae-Youn; Lee, Choon-Soo; Lee, Hyun-Chae; Park, Tai Hyun; Kim, Hyo-Soo; Park, Young-Bae

    2012-01-01

    Background and Objectives Poor homing efficiency is one of the major limitations of current stem cell therapy. Magnetic bionanoparticles (MPs) obtained from Magnetospirillum sp. AMB-1 have a lipid bilayer membrane and ferromagnetic properties. We evaluated a novel priming strategy using MPs to enhance the homing of transplanted progenitor cells to target tissue. Materials and Methods Effects of MP on proliferation, viability, and migration of late human endothelial progenitor cells (EPCs) wer...

  1. Design features of the solenoid magnets for the central cell of the MFTF-B

    The 14 superconducting solenoid magnets which form the central cell of the MFTF-B are being designed and fabricated by General Dynamics for the Lawrence Livermore National Laboratory. Each solenoid coil has a mean diameter of five meters and contains 600 turns of a proven conductor type. Structural loading resulting from credible fault events, cooldown and warmup requirements, and manufacturing processes consistent with other MFTF-B magnets have been considered in the selection of 304 LN as the structural material for the magnet. The solenoid magnets are connected by 24 intercoil beams and 20 solid struts which resist the longitudinal seismic and electromagnetic attractive forces and by 24 hanger/side supports which react magnet dead weight and seismic loads. A modular arrangement of two solenoid coils within a vacuum vessel segment allow for sequential checkout and installation

  2. The magnetic field of Betelgeuse: a local dynamo from giant convection cells?

    Auriere, M; Konstantinova-Antova, R; Perrin, G; Petit, P; Roudier, T

    2010-01-01

    Betelgeuse is an M supergiant with a complex and extended atmosphere, which also harbors spots and giant granules at its surface. A possible magnetic field could contribute to the mass loss and to the heating of the outer atmosphere. We observed Betelgeuse, to directly study and infer the nature of its magnetic field. We used the new-generation spectropolarimeter NARVAL and the least square deconvolution (LSD) method to detect circular polarization within the photospheric absorption lines of Betelgeuse. We have unambiguously detected a weak Stokes V signal in the spectral lines of Betelgeuse, and measured the related surface-averaged longitudinal magnetic field Bl at 6 different epochs over one month. The detected longitudinal field is about one Gauss and is apparently increasing on the time scale of our observations. This work presents the first direct detection of the magnetic field of Betelgeuse. This magnetic field may be associated to the giant convection cells that could enable a "local dynamo:.

  3. Optimization of the magnetic labeling of human neural stem cells and MRI visualization in the hemiparkinsonian rat brain

    Ramos-Gómez, Milagros; Seiz, Emma G; Martínez-Serrano, Alberto

    2015-01-01

    Background Magnetic resonance imaging is the ideal modality for non-invasive in vivo cell tracking allowing for longitudinal studies over time. Cells labeled with superparamagnetic iron oxide nanoparticles have been shown to induce sufficient contrast for in vivo magnetic resonance imaging enabling the in vivo analysis of the final location of the transplanted cells. For magnetic nanoparticles to be useful, a high internalization efficiency of the particles is required without compromising ce...

  4. MULTILEVEL (3D) MICROFLUIDIC TECHNOLOGY FOR AN INNOVATIVE MAGNETIC CELL SEPARATION PLATFORM

    Fouet, Marc; Cargou, Sébastien; Courson, Rémi; Blatché, Charline; Montrose, A.; Reybier, K; Gué, Anne-Marie

    2014-01-01

    We demonstrate a new concept of devices, which by combining 3D fluid engineering and localized mag-netic actuation enables the full integration of a cell tagging and magnetic separation device. We used a low cost, commercially available dry film (EMS Inc, Ohio, USA) that fits microfluidic requirements and gives the possibility to build easily 3D microfluidic structures. The labelling of blood monocytes with su-perparamagnetic particles was performed "up stream" with the aim of a microparticle...

  5. Antibody-Free Magnetic Cell Sorting of Genetically Modified Primary Human CD4+ T Cells by One-Step Streptavidin Affinity Purification

    Matheson, Nicholas J.; Peden, Andrew A.; Lehner, Paul J.

    2014-01-01

    Existing methods for phenotypic selection of genetically modified mammalian cells suffer disadvantages of time, cost and scalability and, where antibodies are used to bind exogenous cell surface markers for magnetic selection, typically yield cells coated with antibody-antigen complexes and beads. To overcome these limitations we have developed a method termed Antibody-Free Magnetic Cell Sorting in which the 38 amino acid Streptavidin Binding Peptide (SBP) is displayed at the cell surface by ...

  6. Investigation of potential fluctuating intra-unit cell magnetic order in cuprates by muon spin relaxation

    Pal, A.; Akintola, K.; Potma, M.; Ishikado, M.; Eisaki, H.; Hardy, W.N.; Bonn, D. A.; Liang, R; Sonier, J. E.

    2016-01-01

    We report low temperature muon spin relaxation (muSR) measurements of the high-transition-temperature (Tc) cuprate superconductors Bi{2+x}Sr{2-x}CaCu2O{8+\\delta} and YBa2Cu3O6.57, aimed at detecting the mysterious intra-unit cell (IUC) magnetic order that has been observed by spin polarized neutron scattering in the pseudogap phase of four different cuprate families. A lack of confirmation by local magnetic probe methods has raised the possibility that the magnetic order fluctuates slowly eno...

  7. MAGNET

    by B. Curé

    2011-01-01

    The magnet operation was very satisfactory till the technical stop at the end of the year 2010. The field was ramped down on 5th December 2010, following the successful regeneration test of the turbine filters at full field on 3rd December 2010. This will limit in the future the quantity of magnet cycles, as it is no longer necessary to ramp down the magnet for this type of intervention. This is made possible by the use of the spare liquid Helium volume to cool the magnet while turbines 1 and 2 are stopped, leaving only the third turbine in operation. This obviously requires full availability of the operators to supervise the operation, as it is not automated. The cryogenics was stopped on 6th December 2010 and the magnet was left without cooling until 18th January 2011, when the cryoplant operation resumed. The magnet temperature reached 93 K. The maintenance of the vacuum pumping was done immediately after the magnet stop, when the magnet was still at very low temperature. Only the vacuum pumping of the ma...

  8. Quantum dots incorporated magnetic nanoparticles for imaging colon carcinoma cells

    Ahmed, Syed Rahin; Dong, Jinhua; Yui, Megumi; Kato, Tatsuya; Lee, Jaebeom; Park, Enoch Y

    2013-01-01

    Background Engineered multifunctional nanoparticles (NPs) have made a tremendous impact on the biomedical sciences, with advances in imaging, sensing and bioseparation. In particular, the combination of optical and magnetic responses through a single particle system allows us to serve as novel multimodal molecular imaging contrast agents in clinical settings. Despite of essential medical imaging modalities and of significant clinical application, only few nanocomposites have been developed wi...

  9. Sterilization of Escherichia coli cells by the application of pulsed magnetic field

    LI Mei; QU Jiu-hui; PENG Yong-zhen

    2004-01-01

    The inactivation of microorganisms by pulsed magnetic field was studied. It was improved that theapplication of electromagnetic pulses evidently causes a lethal effect on E. coli cells suspended in phosphate buffersolution Na2 HPO4 / NaH2 PO4 (0.334/0.867 mmol/L). Experimental results indicated that the survivability( N/N0; whereN0 and N are the number of cells survived per milliliter before and after electromagnetic pulses application,respectively) of E. coli decreased with magnetic field intensity B and treatment time t. It was also found that themedium temperatures, the frequencies of pulse f, and the initial bacterial cell concentrations have determinateinfluences in destruction of E. coli cells by the application of magnetic pulses. The application of an magneticintensity B = 160 mT at pulses frequency f = 62 kHz and treatment time t = 16 h result in a considerable destructionlevels of E. coli cells ( N/N0 = 10-4 ). Possible mechanisms involved in sterilization of the magnetic field treatmentwere discussed. In order to shorten the treatment time, many groups of parallel inductive coil were used. Thepracticability test showed that the treatment time was shortened to 4 h with the application of three groups of parallelcoil when the survivability of E. coli cells was less than 0.01%; and the power consumption was about 0.2 kWh/m3 .

  10. Digitized quantitative electroencephalographic patterns applied as magnetic fields inhibit melanoma cell proliferation in culture.

    Karbowski, Lukasz M; Harribance, Sean L; Buckner, Carly A; Mulligan, Bryce P; Koren, Stanley A; Lafrenie, Robert M; Persinger, Michael A

    2012-08-15

    Weak (1 μT) physiologically patterned magnetic fields produce changes in behavioral, physiological, and cellular activity. In the present experiments 12 temporal samples of the electroencephalographic anomaly and normal activity of a person (SLH) whose proximity reliably affected the brain activity of others were extracted from QEEG data, digitized, and presented as equivalent magnetic field patterns to B16 mouse melanoma cells. Only two of the patterns, both originating from the primary source (right temporal lobe) of the EEG anomaly reduced the cell growth by one-third compared to the other patterns extracted from his QEEG or sham field exposures. In previous experiments these EEG transients were also associated with marked increases in photon emissions from the right side of SLH's head. The results suggest that the intrinsic complexity of electroencephalographic patterns of some people, when amplified appropriately and applied as computer-generated magnetic fields in the three spatial planes, could diminish cancer cell growth. PMID:22750152

  11. Magnetic poly(lactide-co-glycolide) and cellulose particles for MRI-based cell tracking.

    Nkansah, Michael K; Thakral, Durga; Shapiro, Erik M

    2011-06-01

    Biodegradable, superparamagnetic microparticles and nanoparticles of poly(lactide-co-glycolide) (PLGA) and cellulose were designed, fabricated, and characterized for magnetic cell labeling. Monodisperse nanocrystals of magnetite were incorporated into microparticles and nanoparticles of PLGA and cellulose with high efficiency using an oil-in-water single emulsion technique. Superparamagnetic cores had high magnetization (72.1 emu/g). The resulting polymeric particles had smooth surface morphology and high magnetite content (43.3 wt % for PLGA and 69.6 wt % for cellulose). While PLGA and cellulose nanoparticles displayed highest r 2* values per millimole of iron (399 sec(-1) mM(-1) for cellulose and 505 sec(-1) mM(-1) for PLGA), micron-sized PLGA particles had a much higher r 2* per particle than either. After incubation for a month in citrate buffer (pH 5.5), magnetic PLGA particles lost close to 50% of their initial r 2* molar relaxivity, while magnetic cellulose particles remained intact, preserving over 85% of their initial r 2* molar relaxivity. Lastly, mesenchymal stem cells and human breast adenocarcinoma cells were magnetically labeled using these particles with no detectable cytotoxicity. These particles are ideally suited for noninvasive cell tracking in vivo via MRI and due to their vastly different degradation properties, offer unique potential for dedicated use for either short (PLGA-based particles) or long-term (cellulose-based particles) experiments. PMID:21404328

  12. Combination of hyperthermia and photodynamic therapy on mesenchymal stem cell line treated with chloroaluminum phthalocyanine magnetic-nanoemulsion

    de Paula, Leonardo B.; Primo, Fernando L.; Pinto, Marcelo R.; Morais, Paulo C.; Tedesco, Antonio C.

    2015-04-01

    The present study reports on the preparation and the cell viability assay of two nanoemulsions loaded with magnetic nanoparticle and chloroaluminum phthalocyanine. The preparations contain equal amount of chloroaluminum phthalocyanine (0.05 mg/mL) but different contents of magnetic nanoparticle (0.15×1013 or 1.50×1013 particle/mL). The human bone marrow mesenchymal stem cell line was used as the model to assess the cell viability and this type of cell can be used as a model to mimic cancer stem cells. The cell viability assays were performed in isolated as well as under combined magnetic hyperthermia and photodynamic therapy treatments. We found from the cell viability assay that under the hyperthermia treatment (1 MHz and 40 Oe magnetic field amplitude) the cell viability reduction was about 10%, regardless the magnetic nanoparticle content within the magnetic nanoparticle/chloroaluminum phthalocyanine formulation. However, cell viability reduction of about 50% and 60% were found while applying the photodynamic therapy treatment using the magnetic nanoparticle/chloroaluminum phthalocyanine formulation containing 0.15×1013 or 1.50×1013 magnetic particle/mL, respectively. Finally, an average reduction in cell viability of about 66% was found while combining the hyperthermia and photodynamic therapy treatments.

  13. Kinetic of magnetic nanoparticles uptake evaluated by morphometry of mice peritoneal cells

    The development of magnetic fluids (MFs) has led to a wide range of new biomedical applications. Nevertheless, few studies have examined the kinetics of the magnetic nanoparticles (MNPs) internalization by phagocytes. In this study, we present morphometry as a method to quantify the cell surface covered by MNPs. The maximum cell surface covered by MNPs aggregates was 32.5% (8.5 min), 18.3% (24.1 min), and 18.0% (20.2 min) in DMSA, citric acid and dextran-coated MNPs, respectively. We concluded that the phagocytosis process of MNPs is strongly dependent upon the coating species

  14. Magnetic field effects on viscous fingering of a ferrofluid in a radial Hele-Shaw cell

    Herreman, Wietze [Laboratoire Louis Neel, CNRS, BP 166, 38042 Grenoble Cedex 9 (France); Molho, Pierre [Laboratoire Louis Neel, CNRS, BP 166, 38042 Grenoble Cedex 9 (France)]. E-mail: molho@grenoble.cnrs.fr; Neveu, Sophie [LI2C, Universite Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris Cedex 05 (France)

    2005-03-15

    We have studied the effects of a magnetic field on viscous fingering when a ferrofluid is pushed in a more viscous liquid in a circular Hele-Shaw cell. The main effect of the magnetic field, as already known, is to stabilize interfaces parallel to the field and to destabilize interfaces normal to the field. Depending on the growth regime (quasi static, fingering, dendritic growth), which depends on parameters like the cell thickness and oil viscosity, the combination of field effect and anisotropy is analyzed through the various observed patterns.

  15. Synergistic enhancement effect of magnetic nanoparticles on anticancer drug accumulation in cancer cells

    Zhang, Renyun; Wang, Xuemei; Wu, Chunhui; Song, Min; Li, Jingyuan; Lv, Gang; Zhou, Jian; Chen, Chen; Dai, Yongyuan; Gao, Feng; Fu, Degang; Li, Xiaomao; Guan, Zhiqun; Chen, Baoan

    2006-07-01

    Three kinds of magnetic nanoparticle, tetraheptylammonium capped nanoparticles of Fe3O4, Fe2O3 and Ni have been synthesized, and the synergistic effect of these nanoparticles on the drug accumulation of the anticancer drug daunorubicin in leukaemia cells has been explored. Our observations indicate that the enhancement effect of Fe3O4 nanoparticles is much stronger than that of Fe2O3 and Ni nanoparticles, suggesting that nanoparticle surface chemistry and size as well as the unique properties of the magnetic nanoparticles themselves may contribute to the synergistic enhanced effect of the drug uptake of targeted cancer cells.

  16. Contribution of a 300 kHz alternating magnetic field on magnetic hyperthermia treatment of HepG2 cells.

    Wang, Xiaowen; Chen, Youping; Huang, Changshuo; Wang, Xufei; Zhao, Linyun; Zhang, Xiaodong; Tang, Jintian

    2013-02-01

    We investigated the relative contributions of temperature and a 300 kHz alternating magnetic field (AMF) on magnetic hyperthermia treatment (MHT). Our system consisted of an induction coil, which generated AMF by electric current flow, and a newly developed, temperature-controlled circulating water-jacketed glass bottle placed inside the coil. The AMF generator operated at a frequency of 300 kHz with variable field strength ranging from 0 to 11 mT. Four treatment conditions were employed: (A) control (37 °C, 0 mT), (B) AMF exposure (37 °C, 11 mT), (C) hyperthermia (46 °C, 0 mT), and (D) hyperthermia plus AMF exposure (46 °C, 11 mT) for 30 min. Cell viability and apoptotic death rate were estimated. The relative contributions or interactions of hyperthermia (46 °C) and AMF (11 mT) on MHT were evaluated using 2 × 2 factorial experiment analysis. Group A was statistically different (P < 0.05) from each of the other treatments. The observed effects on both cell viability and apoptotic cell death were influenced by temperature (97.36% and 92.15%, respectively), AMF (1.78% and 4.99%, respectively), and the interactions between temperature and AMF (0.25% and 2.36%, respectively). Thus, the effect of hyperthermia was significant. Also, AMF exposure itself might play a role in MHT, although these observations were made in vitro. These findings suggest a possible presence of an AMF effect during clinical magnetic hyperthermia. PMID:23059525

  17. Magnetic resonance spectroscopy in tumor cell lines research

    MRS can be used non-invasively to study the several trace metabolites and energy metabolism in vivo. By quantitatively analyzing the compounds changes we could detect abnormal metabolism in tumor and its surrounding tissue, and estimate tumor infiltration in vivo and vitro. In recent years, MRS has been applied in cell line research and is becoming a promising method. In this article we summarized the applications of MRS in cell lines in studying diagnosis, treatment, and tumor mechanisms. (authors)

  18. MAGNET

    Benoit Curé

    2010-01-01

    Operation of the magnet has gone quite smoothly during the first half of this year. The magnet has been at 4.5K for the full period since January. There was an unplanned short stop due to the CERN-wide power outage on May 28th, which caused a slow dump of the magnet. Since this occurred just before a planned technical stop of the LHC, during which access in the experimental cavern was authorized, it was decided to leave the magnet OFF until 2nd June, when magnet was ramped up again to 3.8T. The magnet system experienced a fault also resulting in a slow dump on April 14th. This was triggered by a thermostat on a filter choke in the 20kA DC power converter. The threshold of this thermostat is 65°C. However, no variation in the water-cooling flow rate or temperature was observed. Vibration may have been the root cause of the fault. All the thermostats have been checked, together with the cables, connectors and the read out card. The tightening of the inductance fixations has also been checked. More tem...

  19. MAGNET

    B. Curé

    2012-01-01

      Following the unexpected magnet stops last August due to sequences of unfortunate events on the services and cryogenics [see CMS internal report], a few more events and initiatives again disrupted the magnet operation. All the magnet parameters stayed at their nominal values during this period without any fault or alarm on the magnet control and safety systems. The magnet was stopped for the September technical stop to allow interventions in the experimental cavern on the detector services. On 1 October, to prepare the transfer of the liquid nitrogen tank on its new location, several control cables had to be removed. One cable was cut mistakenly, causing a digital input card to switch off, resulting in a cold-box (CB) stop. This tank is used for the pre-cooling of the magnet from room temperature down to 80 K, and for this reason it is controlled through the cryogenics control system. Since the connection of the CB was only allowed for a field below 2 T to avoid the risk of triggering a fast d...

  20. MAGNET

    B. Curé

    2012-01-01

      The magnet was energised at the beginning of March 2012 at a low current to check all the MSS safety chains. Then the magnet was ramped up to 3.8 T on 6 March 2012. Unfortunately two days later an unintentional switch OFF of the power converter caused a slow dump. This was due to a misunderstanding of the CCC (CERN Control Centre) concerning the procedure to apply for the CMS converter control according to the beam-mode status at that time. Following this event, the third one since 2009, a discussion was initiated to define possible improvement, not only on software and procedures in the CCC, but also to evaluate the possibility to upgrade the CMS hardware to prevent such discharge from occurring because of incorrect procedure implementations. The magnet operation itself was smooth, and no power cuts took place. As a result, the number of magnetic cycles was reduced to the minimum, with only two full magnetic cycles from 0 T to 3.8 T. Nevertheless the magnet suffered four stops of the cryogeni...

  1. An efficient method of sorting liver stem cells by using immuno-magnetic microbeads

    Yu-Fei He; Yin-Kun Liu; Dong-Mei Gao; Jun Chen; Peng-Yuan Yang

    2006-01-01

    AIM: To develop a method to isolate liver stem cells fast and efficiently.METHODS: Fetal mouse liver cells were characterized by cell surface antigens (c-Kit and CD45/TER119) using flow cytometry. The candidate liver stem cells were sorted by using immuno-magnetic microbeads and identified by clone-forming culture, RT-PCR and immunofluorescence assays.RESULTS: The c-Kit-(CD45/TER119)-cell population with 97.9% of purity were purified by immuno-magnetic microbeads at one time. The yield of this separation was about 6% of the total sorting cells and the cell viability was above 98%. When cultured in vitro these cells had high clone-forming and self-renewing ability and expressed markers of hepatocytes and bile duct cells.Functionally mature hepatocytes were observed after 21 d of culture.CONCLUSION: This method offers an excellent tool for the enrichment of liver stem cells with high purity and viability, which could be used for further studies. It is fast, efficient, simple and not expensive.

  2. Genotoxic Effects of Superconducting Static Magnetic Fields (SMFs) on Wheat (Triticum aestivum) Pollen Mother Cells (PMCs)

    The effects of superconducting static magnetic fields (SMFs) on the pollen mother cells (PMCs) of wheat were investigated in order to evaluate the possible genotoxic effect of such non-ionizing radiation. The seeds of wheat were exposed to static magnetic fields with either different magnetic flux densities (0, 1, 3, 5 and 7 Tesla) for 5 h or different durations (1, 3 and 5 h) at a magnetic flux density of 7 Tesla. The seeds were germinated at 23oC after exposure and the seedlings were transplanted into the field. The PMCs from young wheat ears were taken and slides were made following the conventional method. The genotoxic effect was evaluated in terms of micronucleus (MN), chromosomal bridge, lagging chromosome and fragments in PMCs. Although the exposed groups of a low field intensity (below 5 Tesla) showed no statistically significant difference in the aberration frequency compared with the unexposed control groups and sham exposed groups, a significant increase in the chromosomal bridge, lagging chromosome, triple-polar segregation or micronucleus was observed at a field strength of 5 Tesla or 7 Tesla, respectively. The analysis of dose-effect relationships indicated that the increased frequency of meiotic abnormal cells correlated with the flux density of the magnetic field and duration, but no linear relationship was observed. Such statistically significant differences indicated a potential genotoxic effect of high static magnetic fields above 5 T

  3. Genotoxic Effects of Superconducting Static Magnetic Fields (SMFs) on Wheat (Triticum aestivum) Pollen Mother Cells (PMCs)

    Zhang, Pingping; Yin, Ruochun; Chen, Zhiyou; Wu, Lifang; Yu, Zengliang

    2007-04-01

    The effects of superconducting static magnetic fields (SMFs) on the pollen mother cells (PMCs) of wheat were investigated in order to evaluate the possible genotoxic effect of such non-ionizing radiation. The seeds of wheat were exposed to static magnetic fields with either different magnetic flux densities (0, 1, 3, 5 and 7 Tesla) for 5 h or different durations (1, 3 and 5 h) at a magnetic flux density of 7 Tesla. The seeds were germinated at 23oC after exposure and the seedlings were transplanted into the field. The PMCs from young wheat ears were taken and slides were made following the conventional method. The genotoxic effect was evaluated in terms of micronucleus (MN), chromosomal bridge, lagging chromosome and fragments in PMCs. Although the exposed groups of a low field intensity (below 5 Tesla) showed no statistically significant difference in the aberration frequency compared with the unexposed control groups and sham exposed groups, a significant increase in the chromosomal bridge, lagging chromosome, triple-polar segregation or micronucleus was observed at a field strength of 5 Tesla or 7 Tesla, respectively. The analysis of dose-effect relationships indicated that the increased frequency of meiotic abnormal cells correlated with the flux density of the magnetic field and duration, but no linear relationship was observed. Such statistically significant differences indicated a potential genotoxic effect of high static magnetic fields above 5 T.

  4. Genotoxic Effects of Superconducting Static Magnetic Fields (SMFs) on Wheat (Triticum aestivum) Pollen Mother Cells (PMCs)

    ZHANG Pingping; YIN Ruochun; CHEN Zhiyou; WU Lifang; YU Zengliang

    2007-01-01

    The effects of superconducting static magnetic fields (SMFs) on the pollen mother cells (PMCs) of wheat were investigated in order to evaluate the possible genotoxic effect of such non-ionizing radiation.The seeds of wheat were exposed to static magnetic fields with either different magnetic flux densities (0,1,3,5 and 7 Tesla) for 5 h or different durations (1,3 and 5 h) at a magnetic flux density of 7 Tesla.The seeds were germinated at 23℃ after exposure and the seedlings were transplanted into the field.The PMCs from young wheat ears were taken and slides were made following the conventional method.The genotoxic effect was evaluated in terms of micronucleus (MN),chromosomal bridge,lagging chromosome and fragments in PMCs.Although the exposed groups of a low field intensity (below 5 Tesla) showed no statistically significant difference in the aberration frequency compared with the unexposed control groups and sham exposed groups,a significant increase in the chromosomal bridge,lagging chromosome,triple-polar segregation or micronucleus was observed at a field strength of 5 Tesla or 7 Tesla,respectively.The analysis of dose-effect relationships indicated that the increased frequency of meiotic abnormal cells correlated with the flux density of the magnetic field and duration,but no linear relationship was observed.Such statistically significant differences indicated a potential genotoxic effect of high static magnetic fields above 5 T.

  5. Binding kinetics of magnetic nanoparticles on latex beads and yeast cells studied by magnetorelaxometry

    The ion exchange mediated binding of magnetic nanoparticles (MNP) to modified latex spheres and yeast cells was quantified using magnetorelaxometry. By fitting subsequently recorded relaxation curves, the kinetics of the binding reactions was extracted. The signal of MNP with weak ion exchanger groups bound to latex and yeast cells scales linearly with the concentration of latex beads or yeast cells whereas that of MNP with strong ion exchanger groups is proportional to the square root of concentration. The binding of the latter leads to a much stronger aggregation of yeast cells than the former MNP

  6. Multi-bits memory cell using degenerated magnetic states in a synthetic antiferromagnetic reference layer

    Fukushima, Akio; Yakushiji, Kay; Konoto, Makoto; Kubota, Hitoshi; Imamura, Hiroshi; Yuasa, Shinji

    2016-02-01

    We newly developed a magnetic memory cell having multi-bit function. The memory cell composed of a perpendicularly magnetized magnetic tunnel junction (MB-pMTJ) and a synthetic antiferromagnetic reference layer. The multi-bit function is realized by combining the freedom of states of the magnetic free layer and that in the antiferromagnetically coupled reference layer. The structure of the reference layer is (FeB/Ta/[Co/Pt]3)/Ru/([Co/Pt]6); the top and the bottom layers are coupled through Ru layer where the reference layer has two degrees of freedom of a head-to-head and a bottom-to-bottom magnetic configuration. A four-state memory cell is realized by combination of both degrees of freedom. The states in the reference layer however is hardly detected by the total resistance of MB-pMTJ, because the magnetoresistance effect in the reference layer is negligibly small. That implies that the resistance values for the different states in the reference layer are degenerated. On the other hand, the two different states in the reference layer bring different stray fields to the free layer, which generate two different minor loop with different switching fields. Therefore, the magnetic states in the reference layer can be differentiated by the two-step reading, before and after applying the appropriately pulsed magnetic field which can identify the initial state in the reference layer. This method is similar to distinguishing different magnetic states in an in-plane magnetized spin-valve element. We demonstrated that four different states in the MB-pMTJ can be distinguished by the two-step read-out. The important feature of the two-step reading is a practically large operation margins (large resistance change in reading) which is equal to that of a single MTJ. Even though the two-step reading is a destructive method by which 50% of the magnetic state is changed, this MB-pMTJ is promising for high density non-volatile memory cell with a minor cost of operation speed.

  7. Splenic red pulp macrophages are intrinsically superparamagnetic and contaminate magnetic cell isolates.

    Franken, Lars; Klein, Marika; Spasova, Marina; Elsukova, Anna; Wiedwald, Ulf; Welz, Meike; Knolle, Percy; Farle, Michael; Limmer, Andreas; Kurts, Christian

    2015-01-01

    A main function of splenic red pulp macrophages is the degradation of damaged or aged erythrocytes. Here we show that these macrophages accumulate ferrimagnetic iron oxides that render them intrinsically superparamagnetic. Consequently, these cells routinely contaminate splenic cell isolates obtained with the use of MCS, a technique that has been widely used in immunological research for decades. These contaminations can profoundly alter experimental results. In mice deficient for the transcription factor SpiC, which lack red pulp macrophages, liver Kupffer cells take over the task of erythrocyte degradation and become superparamagnetic. We describe a simple additional magnetic separation step that avoids this problem and substantially improves purity of magnetic cell isolates from the spleen. PMID:26260698

  8. Electrostatically Stabilized Magnetic Nanoparticles - An Optimized Protocol to Label Murine T Cells for in vivo MRI.

    Wuerfel, Eva; Smyth, Maureen; Millward, Jason M; Schellenberger, Eyk; Glumm, Jana; Prozorovski, Timour; Aktas, Orhan; Schulze-Topphoff, Ulf; Schnorr, Jörg; Wagner, Susanne; Taupitz, Matthias; Infante-Duarte, Carmen; Wuerfel, Jens

    2011-01-01

    We present a novel highly efficient protocol to magnetically label T cells applying electrostatically stabilized very small superparamagnetic iron oxide particles (VSOP). Our long-term aim is to use magnetic resonance imaging (MRI) to investigate T cell dynamics in vivo during the course of neuroinflammatory disorders such as experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Encephalitogenic T cells were co-incubated with VSOP, or with protamine-complexed VSOP (VProt), respectively, at different conditions, optimizing concentrations and incubation times. Labeling efficacy was determined by atomic absorption spectrometry as well as histologically, and evaluated on a 7 T MR system. Furthermore, we investigated possible alterations of T cell physiology caused by the labeling procedure. T cell co-incubation with VSOP resulted in an efficient cellular iron uptake. T2 times of labeled cells dropped significantly, resulting in prominent hypointensity on T2*-weighted scans. Optimal labeling efficacy was achieved by VProt (1 mM Fe/ml, 8 h incubation; T2 time shortening of ∼80% compared to untreated cells). Although VSOP promoted T cell proliferation and altered the ratio of T cell subpopulations toward a CD4(+) phenotype, no effects on CD4 T cell proliferation or phenotypic stability were observed by labeling in vitro differentiated Th17 cells with VProt. Yet, high concentrations of intracellular iron oxide might induce alterations in T cell function, which should be considered in cell tagging studies. Moreover, we demonstrated that labeling of encephalitogenic T cells did not affect pathogenicity; labeled T cells were still capable of inducing EAE in susceptible recipient mice. PMID:22203815

  9. Tracking of adipose tissue-derived progenitor cells using two magnetic nanoparticle types

    Kasten, Annika; Siegmund, Birte J. [Department of Oral and Maxillofacial Surgery, Facial Plastic Surgery, Rostock University Medical Center, Schillingallee 35 D-18057 Rostock (Germany); Grüttner, Cordula [Micromod Partikeltechnologie GmbH, Warnemünde, D-18115 Rostock (Germany); Kühn, Jens-Peter [Department of Radiology and Neuroradiology, Greifswald University Medical Center, D-17475 Greifswald (Germany); Frerich, Bernhard, E-mail: bernhard.frerich@med.uni-rostock.de [Department of Oral and Maxillofacial Surgery, Facial Plastic Surgery, Rostock University Medical Center, Schillingallee 35 D-18057 Rostock (Germany)

    2015-04-15

    Magnetic resonance imaging (MRI) is to be considered as an emerging detection technique for cell tracking experiments to evaluate the fate of transplanted progenitor cells and develop successful cell therapies for tissue engineering. Adipose tissue engineering using adipose tissue-derived progenitor cells has been advocated for the cure of soft tissue defects or for persistent soft tissue augmentation. Adipose tissue-derived progenitor cells were differentiated into the adipogenic lineage and labeled with two different types of magnetic iron oxide nanoparticles in varying concentrations which resulted in a concentration-dependent reduction of gene expression of adipogenic differentiation markers, adiponectin and fatty acid-binding protein 4 (FABP4), whereas the metabolic activity was not altered. As a result, only low nanoparticle concentrations for labeling were used for in vivo experiments. Cells were seeded onto collagen scaffolds and subcutaneously implanted into severe combined immunodeficient (SCID) mice. At 24 h as well as 28 days after implantation, MRI analyses were performed visualizing nanoparticle-labeled cells using T2-weighted sequences. The quantification of absolute volume of the scaffolds revealed a decrease of volume over time in all experimental groups. The distribution of nanoparticle-labeled cells within the scaffolds varied likewise over time. - Highlights: • Adipose tissue-derived stem cells (ASC) were labeled with magnetic iron oxide nanoparticles. • Nanoparticles influenced the adipogenic differentiation of ASC. • Labeled cells were seeded onto collagen scaffolds and implanted in SCID mice. • Nanoparticle-labeled cells were visualized in vivo using T2-weighted sequences. • Volume of collagen scaffolds was decreased over time after implantation.

  10. Tracking of adipose tissue-derived progenitor cells using two magnetic nanoparticle types

    Magnetic resonance imaging (MRI) is to be considered as an emerging detection technique for cell tracking experiments to evaluate the fate of transplanted progenitor cells and develop successful cell therapies for tissue engineering. Adipose tissue engineering using adipose tissue-derived progenitor cells has been advocated for the cure of soft tissue defects or for persistent soft tissue augmentation. Adipose tissue-derived progenitor cells were differentiated into the adipogenic lineage and labeled with two different types of magnetic iron oxide nanoparticles in varying concentrations which resulted in a concentration-dependent reduction of gene expression of adipogenic differentiation markers, adiponectin and fatty acid-binding protein 4 (FABP4), whereas the metabolic activity was not altered. As a result, only low nanoparticle concentrations for labeling were used for in vivo experiments. Cells were seeded onto collagen scaffolds and subcutaneously implanted into severe combined immunodeficient (SCID) mice. At 24 h as well as 28 days after implantation, MRI analyses were performed visualizing nanoparticle-labeled cells using T2-weighted sequences. The quantification of absolute volume of the scaffolds revealed a decrease of volume over time in all experimental groups. The distribution of nanoparticle-labeled cells within the scaffolds varied likewise over time. - Highlights: • Adipose tissue-derived stem cells (ASC) were labeled with magnetic iron oxide nanoparticles. • Nanoparticles influenced the adipogenic differentiation of ASC. • Labeled cells were seeded onto collagen scaffolds and implanted in SCID mice. • Nanoparticle-labeled cells were visualized in vivo using T2-weighted sequences. • Volume of collagen scaffolds was decreased over time after implantation

  11. Fluorescent-Magnetic-Biotargeting Multifunctional Nanobioprobes for Detecting and Isolating Multiple Types of Tumor Cells

    Song, Er-Qun; Hu, Jun; Wen, Cong-Ying; Tian, Zhi-Quan; Yu, Xu; Zhang, Zhi-Ling; Shi, Yun-Bo; Pang, Dai-Wen

    2011-01-01

    Fluorescent-magnetic-biotargeting multifunctional nanobioprobes (FMBMNs) have attracted great attention in recent years due to their increasing, important applications in biomedical research, clinical diagnosis, and biomedicine. We have previously developed such nanobioprobes for the detection and isolation of a single kind of tumor cells. Detection and isolation of multiple tumor markers or tumor cells from complex samples sensitively and with high efficiency is critical for the early diagno...

  12. Acute exposure to a 60 Hz magnetic field increases DNA strand breaks in rat brain cells

    Lai, H.; Singh, N.P. [Univ. of Washington, Seattle, WA (United States)

    1997-05-01

    Acute exposure of rats to a 60 Hz magnetic field caused a dose-dependent increase in DNA strand breaks in brain cells of the animals (assayed by a microgel electrophoresis method at 4 h postexposure). An increase in single-strand DNA breaks was observed after exposure to magnetic fields of 0.1, 0.25, and 0.5 mT, whereas an increase in double-strand DNA breaks was observed at 0.25 and 0.5 mT. Because DNA strand breaks may affect cellular functions, lead to carcinogenesis and cell death, and be related to onset of neurodegenerative diseases, the data may have important implications for the possible health effects of exposure to 60 Hz magnetic fields.

  13. Magnetic Nanocomposite Scaffold-Induced Stimulation of Migration and Odontogenesis of Human Dental Pulp Cells through Integrin Signaling Pathways

    Yun, Hyung-Mun; Lee, Eui-Suk; Kim, Mi-joo; Kim, Jung-Ju; Lee, Jung-Hwan; Hae-Hyoung LEE; Park, Kyung-Ran; Yi, Jin-Kyu; Kim, Hae-Won; Kim, Eun-Cheol

    2015-01-01

    Magnetism is an intriguing physical cue that can alter the behaviors of a broad range of cells. Nanocomposite scaffolds that exhibit magnetic properties are thus considered useful 3D matrix for culture of cells and their fate control in repair and regeneration processes. Here we produced magnetic nanocomposite scaffolds made of magnetite nanoparticles (MNPs) and polycaprolactone (PCL), and the effects of the scaffolds on the adhesion, growth, migration and odontogenic differentiation of human...

  14. Effects of Static Magnetic Field on Growth of Leptospire, Leptospira interrogans serovar canicola: Immunoreactivity and Cell Division

    Triampo, Wannapong; Doungchawee, Galayanee; Triampo, Darapond; Wong-Ekkabut, Jirasak; Tang, I-Ming

    2004-01-01

    The effects of the exposure of the bacterium, Leptospira interrogans serovar canicola to a constant magnetic field with magnetic flux density from a permanent ferrite magnet = 140 mT were studied. Changes in Leptospira cells after their exposure to the field were determined on the basis of changes in their growth behavior and agglutination immunoreactivity with a homologous antiserum using darkfield microscopy together with visual imaging. The data showed that the exposed Leptospira cells hav...

  15. Immunomagnetic separation of Salmonella cells using newly designed magnetic carrriers

    Rittich, B.; Španová, A.; Sučiková, J.; Štrumcová, S.; Lenfeld, Jiří; Horák, Daniel

    Frankfurt am Main : Dechema e. V. Society for Chemical Engineering and Biotechnology, 2002. s. P28. [International Symposium on the Separation of Proteins, Peptides and Polynucleotides /22./. 10.11.2002-13.11.2002, Heidelberg] R&D Projects: GA AV ČR KSK4055109 Keywords : Salmonella cells Subject RIV: CC - Organic Chemistry

  16. Magnetic Decoration and Labeling of Prokaryotic and Eukaryotic Cells

    Šafařík, Ivo; Maděrová, Zdeňka; Pospišková, K.; Horská, Kateřina; Šafaříková, Miroslava

    Cambridge: Royal society of chemistry, 2014 - (Fakhrullin, R.; Choi, I.; Lvov, Y.), s. 185-215 ISBN 978-1-84973-902-3 R&D Projects: GA MŠk(CZ) LD13023; GA ČR(CZ) GAP503/11/2263 Institutional support: RVO:67179843 Keywords : eukaryotic cells * nanoparticles * microparticles * organic and inorganic xenobiotics Subject RIV: DJ - Water Pollution ; Quality

  17. MAGNET

    Benoit Curé

    2010-01-01

    The magnet was successfully operated at the end of the year 2009 despite some technical problems on the cryogenics. The magnet was ramped up to 3.8 T at the end of November until December 16th when the shutdown started. The magnet operation met a few unexpected stops. The field was reduced to 3.5 T for about 5 hours on December 3rd due to a faulty pressure sensor on the helium compressor. The following day the CERN CCC stopped unintentionally the power converters of the LHC and the experiments, triggering a ramp down that was stopped at 2.7 T. The magnet was back at 3.8 T about 6 hours after CCC sent the CERN-wide command. Three days later, a slow dump was triggered due to a stop of the pump feeding the power converter water-cooling circuit, during an intervention on the water-cooling plant done after several disturbances on the electrical distribution network. The magnet was back at 3.8 T in the evening the same day. On December 10th a break occurred in one turbine of the cold box producing the liquid ...

  18. MAGNET

    B. Curé

    2013-01-01

      The magnet was operated without any problem until the end of the LHC run in February 2013, apart from a CERN-wide power glitch on 10 January 2013 that affected the CMS refrigerator, causing a ramp down to 2 T in order to reconnect the coldbox. Another CERN-wide power glitch on 15 January 2013 didn’t affect the magnet subsystems, the cryoplant or the power converter. At the end of the magnet run, the reconnection of the coldbox at 2.5 T was tested. The process will be updated, in particular the parameters of some PID valve controllers. The helium flow of the current leads was reduced but only for a few seconds. The exercise will be repeated with the revised parameters to validate the automatic reconnection process of the coldbox. During LS1, the water-cooling services will be reduced and many interventions are planned on the electrical services. Therefore, the magnet cryogenics and subsystems will be stopped for several months, and the magnet cannot be kept cold. In order to avoid unc...

  19. MAGNET

    B. Curé

    2012-01-01

      The magnet and its sub-systems were stopped at the beginning of the winter shutdown on 8th December 2011. The magnet was left without cooling during the cryogenics maintenance until 17th January 2012, when the cryoplant operation resumed. The magnet temperature reached 93 K. The vacuum pumping was maintained during this period. During this shutdown, the yearly maintenance was performed on the cryogenics, the vacuum pumps, the magnet control and safety systems, and the power converter and discharge lines. Several preventive actions led to the replacement of the electrovalve command coils, and the 20A DC power supplies of the magnet control system. The filters were cleaned on the demineralised water circuits. The oil of the diffusion pumps was changed. On the cryogenics, warm nitrogen at 343 K was circulated in the cold box to regenerate the filters and the heat exchangers. The coalescing filters have been replaced at the inlet of both the turbines and the lubricant trapping unit. The active cha...

  20. MAGNET

    B. Curé

    2011-01-01

    The CMS magnet has been running steadily and smoothly since the summer, with no detected flaw. The magnet instrumentation is entirely operational and all the parameters are at their nominal values. Three power cuts on the electrical network affected the magnet run in the past five months, with no impact on the data-taking as the accelerator was also affected at the same time. On 22nd June, a thunderstorm caused a power glitch on the service electrical network. The primary water cooling at Point 5 was stopped. Despite a quick restart of the water cooling, the inlet temperature of the demineralised water on the busbar cooling circuit increased by 5 °C, up to 23.3 °C. It was kept below the threshold of 27 °C by switching off other cooling circuits to avoid the trigger of a slow dump of the magnet. The cold box of the cryogenics also stopped. Part of the spare liquid helium volume was used to maintain the cooling of the magnet at 4.5 K. The operators of the cryogenics quickly restarted ...

  1. Combination of hyperthermia and photodynamic therapy on mesenchymal stem cell line treated with chloroaluminum phthalocyanine magnetic-nanoemulsion

    Paula, Leonardo B. de [Departamento de Química, Centro de Nanotecnologia e Engenharia Tecidual, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP 14040-901 (Brazil); Departamento de Genética, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP 14049-900 (Brazil); Primo, Fernando L. [Departamento de Química, Centro de Nanotecnologia e Engenharia Tecidual, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP 14040-901 (Brazil); Nanophoton Company, SUPERA Innovation and Technology Park, Av. Doutora Nadir de Aguiar, 1805, Universidade de São Paulo, Ribeirão Preto, P 14056-680 (Brazil); Pinto, Marcelo R. [Departamento de Química, Laboratório de Enzimologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP 14040-901 (Brazil); Morais, Paulo C. [Instituto de Física, Universidade de Brasília, Brasília, DF 70910-900 (Brazil); School of Automation, Huazhong University of Science and Technology, Wuhan 430074 (China); and others

    2015-04-15

    The present study reports on the preparation and the cell viability assay of two nanoemulsions loaded with magnetic nanoparticle and chloroaluminum phthalocyanine. The preparations contain equal amount of chloroaluminum phthalocyanine (0.05 mg/mL) but different contents of magnetic nanoparticle (0.15×10{sup 13} or 1.50×10{sup 13} particle/mL). The human bone marrow mesenchymal stem cell line was used as the model to assess the cell viability and this type of cell can be used as a model to mimic cancer stem cells. The cell viability assays were performed in isolated as well as under combined magnetic hyperthermia and photodynamic therapy treatments. We found from the cell viability assay that under the hyperthermia treatment (1 MHz and 40 Oe magnetic field amplitude) the cell viability reduction was about 10%, regardless the magnetic nanoparticle content within the magnetic nanoparticle/chloroaluminum phthalocyanine formulation. However, cell viability reduction of about 50% and 60% were found while applying the photodynamic therapy treatment using the magnetic nanoparticle/chloroaluminum phthalocyanine formulation containing 0.15×10{sup 13} or 1.50×10{sup 13} magnetic particle/mL, respectively. Finally, an average reduction in cell viability of about 66% was found while combining the hyperthermia and photodynamic therapy treatments. - Highlights: • Current protocols in nanotechnology allow for biocompatible magnetic nanoparticles being associated with photosensitizer photoactive drugs, which could lead to perfectly controlled drug release. • The combination of the HPT and PDT therapies can be useful to develop further protocols for both advanced in vitro and in vivo assays. • Magnetic nanodevices associated with therapies have led to the decreased of proliferation of cell population that provides a favorable environment for tumor progression.

  2. Combination of hyperthermia and photodynamic therapy on mesenchymal stem cell line treated with chloroaluminum phthalocyanine magnetic-nanoemulsion

    The present study reports on the preparation and the cell viability assay of two nanoemulsions loaded with magnetic nanoparticle and chloroaluminum phthalocyanine. The preparations contain equal amount of chloroaluminum phthalocyanine (0.05 mg/mL) but different contents of magnetic nanoparticle (0.15×1013 or 1.50×1013 particle/mL). The human bone marrow mesenchymal stem cell line was used as the model to assess the cell viability and this type of cell can be used as a model to mimic cancer stem cells. The cell viability assays were performed in isolated as well as under combined magnetic hyperthermia and photodynamic therapy treatments. We found from the cell viability assay that under the hyperthermia treatment (1 MHz and 40 Oe magnetic field amplitude) the cell viability reduction was about 10%, regardless the magnetic nanoparticle content within the magnetic nanoparticle/chloroaluminum phthalocyanine formulation. However, cell viability reduction of about 50% and 60% were found while applying the photodynamic therapy treatment using the magnetic nanoparticle/chloroaluminum phthalocyanine formulation containing 0.15×1013 or 1.50×1013 magnetic particle/mL, respectively. Finally, an average reduction in cell viability of about 66% was found while combining the hyperthermia and photodynamic therapy treatments. - Highlights: • Current protocols in nanotechnology allow for biocompatible magnetic nanoparticles being associated with photosensitizer photoactive drugs, which could lead to perfectly controlled drug release. • The combination of the HPT and PDT therapies can be useful to develop further protocols for both advanced in vitro and in vivo assays. • Magnetic nanodevices associated with therapies have led to the decreased of proliferation of cell population that provides a favorable environment for tumor progression

  3. Magnetic resonance tracking of implanted adult and embryonic stem cells in injured brain and spinal cord

    Syková, Eva; Jendelová, Pavla

    2005-01-01

    Roč. 1049, - (2005), s. 146-160. ISSN 0077-8923 R&D Projects: GA ČR GA304/03/1189; GA MŠk(CZ) 1M0538 Institutional research plan: CEZ:AV0Z5039906 Keywords : cell transplantation * magnetic resonance Subject RIV: FJ - Surgery incl. Transplants Impact factor: 1.971, year: 2005

  4. Modulation of monocytic leukemia cell function and survival by highgradient magnetic fields and mathematical modeling studies

    Zablotskyy, Vitaliy A.; Syrovets, T.; Schmidt, Z.W.; Dejneka, Alexandr; Simmet, T.

    2014-01-01

    Roč. 35, č. 10 (2014), s. 3164-3171. ISSN 0142-9612 Grant ostatní: AV ČR(CZ) M100101219 Institutional support: RVO:68378271 Keywords : magnetic field * cell proliferation * leukemia * apoptosis * modeling Subject RIV: BO - Biophysics Impact factor: 8.557, year: 2014

  5. Imaging Microwave and DC Magnetic Fields in a Vapor-Cell Rb Atomic Clock

    Affolderbach, Christoph; Bandi, Thejesh; Horsley, Andrew; Treutlein, Philipp; Mileti, Gaetano

    2015-01-01

    We report on the experimental measurement of the DC and microwave magnetic field distributions inside a recently-developed compact magnetron-type microwave cavity, mounted inside the physics package of a high-performance vapor-cell atomic frequency standard. Images of the microwave field distribution with sub-100 $\\mu$m lateral spatial resolution are obtained by pulsed optical-microwave Rabi measurements, using the Rb atoms inside the cell as field probes and detecting with a CCD camera. Asymmetries observed in the microwave field images can be attributed to the precise practical realization of the cavity and the Rb vapor cell. Similar spatially-resolved images of the DC magnetic field distribution are obtained by Ramsey-type measurements. The T2 relaxation time in the Rb vapor cell is found to be position dependent, and correlates with the gradient of the DC magnetic field. The presented method is highly useful for experimental in-situ characterization of DC magnetic fields and resonant microwave structures,...

  6. Towards The Generation of Functionalized Magnetic Nanowires to Target Leukemic Cells

    Alsharif, Nouf

    2016-04-01

    In recent years, magnetic nanowires (NWs) have been widely used for their therapeutic potential in biomedical applications. The use of iron (Fe) NWs combines two important properties, biocompatibility and remote manipulation by magnetic fields. In addition the NWs can be coated and functionalized to target cells of interest and, upon exposure to an alternating magnetic field, have been shown to induce cell death on several types of adherent cells, including several cancer cell types. For suspension cells, however, using these NWs has been much less effective primarily due to the free-floating nature of the cells minimizing the interaction between them and the NWs. Leukemic cells express higher levels of the cell surface marker CD44 (Braumüller, Gansauge, Ramadani, & Gansauge, 2000), compared to normal blood cells. The goal of this study was to functionalize Fe NWs with a specific monoclonal antibody towards CD44 in order to target leukemic cells (HL-60 cells). This approach is expected to increase the probability of a specific binding to occur between HL-60 cells and Fe NWs. Fe NWs were fabricated with an average diameter of 30-40 nm and a length around 3-4 μm. Then, they were coated with both 3-Aminopropyl-triethoxysilane and bovine serum albumin (BSA) in order to conjugate them with an anti-CD44 antibody (i.e. anti-CD44-iron NWs). The antibody interacts with the amine group in the BSA via the 1-Ethyl-3-3-dimethylaminopropyl-carbodiimide and N-Hydroxysuccinimide coupling. The NWs functionalization was confirmed using a number of approaches including: infrared spectroscopy, Nanodrop to measure the concentration of CD44 antibody, as well as fluorescent-labeled secondary antibody staining to detect the primary CD44 antibody. To confirm that the anti-CD44-iron NWs and bare Fe NWs, in the absence of a magnetic field, were not toxic to HL-60 cells, cytotoxicity assays using XTT (2,3-Bis-2-Methoxy-4-Nitro-5-Sulfophenyl-2H-Tetrazolium-5-Carboxanilide) were performed and

  7. Three-dimensional cell culturing by magnetic levitation for evaluating efficacy/toxicity of photodynamic therapy

    Sabino, Luis G.; Menezes, Priscila F. C.; Bagnato, Vanderlei S.; Souza, Glauco; Killian, Thomas C.; Kurachi, Cristina

    2014-03-01

    We used three dimensional cell cultures (3D) based on the magnetic levitation method (MLM) to evaluate cytotoxicity of photodynamic therapy (PDT). First, we decorated Hep G2 and MDA-MB-321 cells with NanoShuttle by introducing it in the media and incubated overnight. Next day, we transferred the cells to a 6-well plate and placed a magnetic driver on the top of the plate to start levitation. We monitored the formation of the 3D cell culture by optical microscopy and after four days, we added the photosensitizer Photogem (PG) in the culture media in concentrations of 50, 25, 12.5, 6.25μg/ml. We incubated them for 24 hours, after that we washed the cultures with PBS and added fresh media. Samples were then illuminated for 600s using a 630nm LED-based device, generating light intensities of 30 mW/cm2 in a total light fluence of 18 J/cm2. Following the illumination, we added fresh media, and 30 hours later, the 3D structures were broken using a pipettor and the cells seeded in 96 well plates, 105 cells per well, with a magnetic drive placed on the bottom of the plate to create cell culture dots. After 24 hours, we used a MTT assay to evaluate PDT cytotoxicity. The PDT effect, evaluated by the half maximal effective concentration (EC50), in MDA-MB-231 cells (EC50 =3.14 μg/ml) is more aggressive compared to the effect of PDT in Hep G2 cells (EC50 = 7.48 μg/ml). It suggests that the cell culture structure and its interaction facilitated the PG uptake and consequently elevated the Photodynamic effect for MDA-MB-231.

  8. Hepatic involvement of Langerhans cell histiocytosis in children - imaging findings of computed tomography, magnetic resonance imaging and magnetic resonance cholangiopancreatography

    Shi, Yingyan; Qiao, Zhongwei; Gong, Ying; Yang, Haowei; Li, Guoping; Pa, Mier [Children' s Hospital of Fudan University, Department of Radiology, Shanghai (China); Xia, Chunmei [Shanghai Medical College of Fudan University, Physiology and Pathophysiology Department, Shanghai (China)

    2014-06-15

    Langerhans cell histiocytosis is a rare disease that occurs mainly in children, and hepatic involvement is generally a poor prognostic factor. To describe CT and MRI findings of hepatic involvement of Langerhans cell histiocytosis in children, especially the abnormal bile duct manifestation on magnetic resonance cholangiopancreatography (MRCP). Thirteen children (seven boys, six girls; mean age 28.9 months) were diagnosed with disseminated Langerhans cell histiocytosis. They underwent CT (n = 5) or MRI (n = 4), or CT and MRI examinations (n = 4) to evaluate the liver involvement. Periportal abnormalities presented as band-like or nodular lesions on CT and MRI in all 13 children. The hepatic parenchymal lesions were found in the peripheral regions of the liver in seven children, including multiple nodules on MRI (n = 6), and cystic-like lesions on CT and MRI (n = 3). In 11 of the 13 children the dilatations of the bile ducts were observed on CT and MRI. Eight of the 13 children underwent MR cholangiopancreatography, which demonstrated stenoses or segmental stenoses with slight dilatation of the central bile ducts, including the common hepatic duct and its first-order branches. The peripheral bile ducts in these children showed segmental dilatations and stenoses. Stenosis of the central bile ducts revealed by MR cholangiopancreatography was the most significant finding of liver involvement in Langerhans cell histiocytosis in children. (orig.)

  9. Hepatic involvement of Langerhans cell histiocytosis in children - imaging findings of computed tomography, magnetic resonance imaging and magnetic resonance cholangiopancreatography

    Langerhans cell histiocytosis is a rare disease that occurs mainly in children, and hepatic involvement is generally a poor prognostic factor. To describe CT and MRI findings of hepatic involvement of Langerhans cell histiocytosis in children, especially the abnormal bile duct manifestation on magnetic resonance cholangiopancreatography (MRCP). Thirteen children (seven boys, six girls; mean age 28.9 months) were diagnosed with disseminated Langerhans cell histiocytosis. They underwent CT (n = 5) or MRI (n = 4), or CT and MRI examinations (n = 4) to evaluate the liver involvement. Periportal abnormalities presented as band-like or nodular lesions on CT and MRI in all 13 children. The hepatic parenchymal lesions were found in the peripheral regions of the liver in seven children, including multiple nodules on MRI (n = 6), and cystic-like lesions on CT and MRI (n = 3). In 11 of the 13 children the dilatations of the bile ducts were observed on CT and MRI. Eight of the 13 children underwent MR cholangiopancreatography, which demonstrated stenoses or segmental stenoses with slight dilatation of the central bile ducts, including the common hepatic duct and its first-order branches. The peripheral bile ducts in these children showed segmental dilatations and stenoses. Stenosis of the central bile ducts revealed by MR cholangiopancreatography was the most significant finding of liver involvement in Langerhans cell histiocytosis in children. (orig.)

  10. Tracking of iron-labeled human neural stem cells by magnetic resonance imaging in cell replacement therapy for Parkinson’s disease

    Milagros Ramos-Gmez; Alberto Martnez-Serrano

    2016-01-01

    Human neural stem cells (hNSCs) derived from the ventral mesencephalon are powerful research tools and candidates for cell therapies in Parkinson’s disease. However, their clinical translation has not been fully realized due, in part, to the limited ability to track stem cell regional localization and survival over long periods of time afterin vivo transplantation. Magnetic resonance imaging provides an excellent non-invasive method to study the fate of transplanted cellsin vivo. For magnetic resonance imaging cell tracking, cells need to be labeled with a contrast agent, such as magnetic nanoparticles, at a concentration high enough to be easily detected by magnetic resonance imaging. Grafting of human neural stem cells labeled with magnetic nanoparticles allows cell tracking by magnetic resonance imaging without impairment of cell survival, prolif-eration, self-renewal, and multipotency. However, the results reviewed here suggest that in long term grafting, activated microglia and macrophages could contribute to magnetic resonance imaging signal by engulifng dead labeled cells or iron nanoparticles dispersed freely in the brain parenchyma over time.

  11. Immunocapture of CD133-positive cells from human cancer cell lines by using monodisperse magnetic poly(glycidyl methacrylate) microspheres containing amino groups

    Magnetic poly(glycidyl methacrylate)-based macroporous microspheres with an average particle size of 4.2 μm were prepared using a modified multi-step swelling polymerization method and by introducing amino functionality on their surfaces. Antibody molecules were oxidized on their carbohydrate moieties and bound to the amino-containing magnetic microspheres via a site-directed procedure. CD133-positive cells could be effectively captured from human cancer cell lines (HepG2, HCT116, MCF7, and IMR-32) by using magnetic microspheres conjugated to an anti-human CD133 antibody. After further culture, the immunocaptured CD133-expressing cells from IMR-32 proliferated and gradually detached from the magnetic microspheres. Flow-cytometric analysis confirmed the enrichment of CD133-expressing cells by using the antibody-bound magnetic microspheres. Such microspheres suitable for immunocapture are very promising for cancer diagnosis because the CD133-expressing cells in cancer cell lines have been suggested to be cancer stem cells. - Highlights: • Multi-step swelling polymerization produced poly(glycidyl methacrylate) microspheres. • Anti-human CD133 antibodies were bound to the amino-containing magnetic microspheres. • CD133-positive cells were effectively captured from human cancer cell lines. • Immunocaptured CD133-expressing cells proliferated and were detached from microspheres. • Enrichment of CD133-expressing cells was confirmed by flow-cytometric analysis

  12. Biotechnological promises of Fe-filled CNTs for cell shepherding and magnetic fluid hyperthermia applications

    Pineux, Florent; Marega, Riccardo; Stopin, Antoine; La Torre, Alessandro; Garcia, Yann; Devlin, Eamonn; Michiels, Carine; N. Khlobystov, Andrei; Bonifazi, Davide

    2015-12-01

    Fe-filled carbon nanotubes (Fe@CNTs) recently emerged as an effective class of hybrid nanoparticles for biotechnological applications, such as magnetic cell sorting and magnetic fluid hyperthermia. Aiming at studying the effects of both the Fe loading and the magnetocrystalline characteristics in these applications, we describe herein the preparation of Fe@CNTs containing different Fe phases that, upon functionalization with the antibody Cetuximab (Ctxb), allow the targeting of cancer cells. Our experimental findings reveal that an optimal Ctxb/Fe weight ratio of 1.2 is needed for efficient magnetic cell shepherding, whereas enhanced MFH-induced mortality (70 vs. 15%) can be reached with hybrids enriched in the coercive Fe3C phase. These results suggest that a synergistic effect between the Ab loading and the Fe distribution in each nanotube exists, for which the maximum shepherding and hyperthermia effects are observed when higher densities of Fe@CNTs featuring the more coercive phase are interfaced with the cells.Fe-filled carbon nanotubes (Fe@CNTs) recently emerged as an effective class of hybrid nanoparticles for biotechnological applications, such as magnetic cell sorting and magnetic fluid hyperthermia. Aiming at studying the effects of both the Fe loading and the magnetocrystalline characteristics in these applications, we describe herein the preparation of Fe@CNTs containing different Fe phases that, upon functionalization with the antibody Cetuximab (Ctxb), allow the targeting of cancer cells. Our experimental findings reveal that an optimal Ctxb/Fe weight ratio of 1.2 is needed for efficient magnetic cell shepherding, whereas enhanced MFH-induced mortality (70 vs. 15%) can be reached with hybrids enriched in the coercive Fe3C phase. These results suggest that a synergistic effect between the Ab loading and the Fe distribution in each nanotube exists, for which the maximum shepherding and hyperthermia effects are observed when higher densities of Fe

  13. Tracking of adipose tissue-derived progenitor cells using two magnetic nanoparticle types

    Kasten, Annika; Siegmund, Birte J.; Grüttner, Cordula; Kühn, Jens-Peter; Frerich, Bernhard

    2015-04-01

    Magnetic resonance imaging (MRI) is to be considered as an emerging detection technique for cell tracking experiments to evaluate the fate of transplanted progenitor cells and develop successful cell therapies for tissue engineering. Adipose tissue engineering using adipose tissue-derived progenitor cells has been advocated for the cure of soft tissue defects or for persistent soft tissue augmentation. Adipose tissue-derived progenitor cells were differentiated into the adipogenic lineage and labeled with two different types of magnetic iron oxide nanoparticles in varying concentrations which resulted in a concentration-dependent reduction of gene expression of adipogenic differentiation markers, adiponectin and fatty acid-binding protein 4 (FABP4), whereas the metabolic activity was not altered. As a result, only low nanoparticle concentrations for labeling were used for in vivo experiments. Cells were seeded onto collagen scaffolds and subcutaneously implanted into severe combined immunodeficient (SCID) mice. At 24 h as well as 28 days after implantation, MRI analyses were performed visualizing nanoparticle-labeled cells using T2-weighted sequences. The quantification of absolute volume of the scaffolds revealed a decrease of volume over time in all experimental groups. The distribution of nanoparticle-labeled cells within the scaffolds varied likewise over time.

  14. Optimization of Human Corneal Endothelial Cells for Culture: The Removal of Corneal Stromal Fibroblast Contamination Using Magnetic Cell Separation

    Gary S. L. Peh

    2012-01-01

    Full Text Available The culture of human corneal endothelial cells (CECs is critical for the development of suitable graft alternative on biodegradable material, specifically for endothelial keratoplasty, which can potentially alleviate the global shortage of transplant-grade donor corneas available. However, the propagation of slow proliferative CECs in vitro can be hindered by rapid growing stromal corneal fibroblasts (CSFs that may be coisolated in some cases. The purpose of this study was to evaluate a strategy using magnetic cell separation (MACS technique to deplete the contaminating CSFs from CEC cultures using antifibroblast magnetic microbeads. Separated “labeled” and “flow-through” cell fractions were collected separately, cultured, and morphologically assessed. Cells from the “flow-through” fraction displayed compact polygonal morphology and expressed Na+/K+ATPase indicative of corneal endothelial cells, whilst cells from the “labeled” fraction were mostly elongated and fibroblastic. A separation efficacy of 96.88% was observed. Hence, MACS technique can be useful in the depletion of contaminating CSFs from within a culture of CECs.

  15. MAGNET

    B. Curé

    2011-01-01

    The magnet ran smoothly in the last few months until a fast dump occurred on 9th May 2011. Fortunately, this occurred in the afternoon of the first day of the technical stop. The fast dump was due to a valve position controller that caused the sudden closure of a valve. This valve is used to regulate the helium flow on one of the two current leads, which electrically connects the coil at 4.5 K to the busbars at room temperature. With no helium flow on the lead, the voltage drop and the temperatures across the leads increase up to the defined thresholds, triggering a fast dump through the Magnet Safety System (MSS). The automatic reaction triggered by the MSS worked properly. The helium release was limited as the pressure rise was just at the limit of the safety valve opening pressure. The average temperature of the magnet reached 72 K. It took four days to recover the temperature and refill the helium volumes. The faulty valve controller was replaced by a spare one before the magnet ramp-up resumed....

  16. Microfluidic synthesis of microfibers for magnetic-responsive controlled drug release and cell culture.

    Yung-Sheng Lin

    Full Text Available This study demonstrated the fabrication of alginate microfibers using a modular microfluidic system for magnetic-responsive controlled drug release and cell culture. A novel two-dimensional fluid-focusing technique with multi-inlets and junctions was used to spatiotemporally control the continuous laminar flow of alginate solutions. The diameter of the manufactured microfibers, which ranged from 211 µm to 364 µm, could be well controlled by changing the flow rate of the continuous phase. While the model drug, diclofenac, was encapsulated into microfibers, the drug release profile exhibited the characteristic of a proper and steady release. Furthermore, the diclofenac release kinetics from the magnetic iron oxide-loaded microfibers could be controlled externally, allowing for a rapid drug release by applying a magnetic force. In addition, the successful culture of glioblastoma multiforme cells in the microfibers demonstrated a good structural integrity and environment to grow cells that could be applied in drug screening for targeting cancer cells. The proposed microfluidic system has the advantages of ease of fabrication, simplicity, and a fast and low-cost process that is capable of generating functional microfibers with the potential for biomedical applications, such as drug controlled release and cell culture.

  17. A tunable cancer cell filter using magnetic beads: cellular and fluid dynamic simulations

    Gusenbauer, Markus; Bance, Simon; Exl, Lukas; Reichel, Franz; Oezelt, Harald; Schrefl, Thomas

    2011-01-01

    In the field of biomedicine magnetic beads are used for drug delivery and to treat hyperthermia. Here we propose to use self-organized bead structures to isolate circulating tumor cells using lab-on-chip technologies. Typically blood flows past microposts functionalized with antibodies for circulating tumor cells. Creating these microposts with interacting magnetic beads makes it possible to tune the geometry in size, position and shape. We develop a simulation tool that combines micromagnetics, discrete particle dynamics and fluid dynamics, in order to design micropost arrays made of interacting beads. For the simulation of blood flow we use the Lattice-Boltzmann method with immersed elastic blood cell models. Parallelization distributes large fluid and particle dynamic simulations over available resources to reduce overall calculation time.

  18. Highly efficient mesenchymal stem cell proliferation on poly-epsilon-caprolactone nanofibers with embedded magnetic nanoparticles

    Daňková, Jana; Buzgo, Matej; Vejpravová, Jana; Kubíčková, Simona; Sovková, Věra; Vysloužilová, L.; Mantlíková, Alice; Nečas, A.; Amler, Evžen

    2015-01-01

    Roč. 10, č. 2015 (2015), s. 7307-7317. ISSN 1176-9114 R&D Projects: GA ČR(CZ) GA15-15697S; GA MŠk(CZ) LO1508; GA MŠk(CZ) LO1309; GA MŠk(CZ) 7E12057 Grant ostatní: FP7 MULTIFUN(XE) 262943 Institutional support: RVO:68378041 ; RVO:68378271 Keywords : magnetic particles * mesenchymal stem cells * nanofibers Subject RIV: FP - Other Medical Disciplines; BM - Solid Matter Physics ; Magnetism (FZU-D)

  19. MPQ-cytometry: a magnetism-based method for quantification of nanoparticle-cell interactions

    Shipunova, V. O.; Nikitin, M. P.; Nikitin, P. I.; Deyev, S. M.

    2016-06-01

    Precise quantification of interactions between nanoparticles and living cells is among the imperative tasks for research in nanobiotechnology, nanotoxicology and biomedicine. To meet the challenge, a rapid method called MPQ-cytometry is developed, which measures the integral non-linear response produced by magnetically labeled nanoparticles in a cell sample with an original magnetic particle quantification (MPQ) technique. MPQ-cytometry provides a sensitivity limit 0.33 ng of nanoparticles and is devoid of a background signal present in many label-based assays. Each measurement takes only a few seconds, and no complicated sample preparation or data processing is required. The capabilities of the method have been demonstrated by quantification of interactions of iron oxide nanoparticles with eukaryotic cells. The total amount of targeted nanoparticles that specifically recognized the HER2/neu oncomarker on the human cancer cell surface was successfully measured, the specificity of interaction permitting the detection of HER2/neu positive cells in a cell mixture. Moreover, it has been shown that MPQ-cytometry analysis of a HER2/neu-specific iron oxide nanoparticle interaction with six cell lines of different tissue origins quantitatively reflects the HER2/neu status of the cells. High correlation of MPQ-cytometry data with those obtained by three other commonly used in molecular and cell biology methods supports consideration of this method as a prospective alternative for both quantifying cell-bound nanoparticles and estimating the expression level of cell surface antigens. The proposed method does not require expensive sophisticated equipment or highly skilled personnel and it can be easily applied for rapid diagnostics, especially under field conditions.Precise quantification of interactions between nanoparticles and living cells is among the imperative tasks for research in nanobiotechnology, nanotoxicology and biomedicine. To meet the challenge, a rapid method

  20. Development of Multifunctional Magnetic Nanoparticles for Genetic Engineering and Tracking of Neural Stem Cells.

    Adams, Christopher; Israel, Liron Limor; Ostrovsky, Stella; Taylor, Arthur; Poptani, Harish; Lellouche, Jean-Paul; Chari, Divya

    2016-04-01

    Genetic modification of cell transplant populations and cell tracking ability are key underpinnings for effective cell therapies. Current strategies to achieve these goals utilize methods which are unsuitable for clinical translation because of related safety issues, and multiple protocol steps adding to cost and complexity. Multifunctional magnetic nanoparticles (MNPs) offering dual mode gene delivery and imaging contrast capacity offer a valuable tool in this context. Despite their key benefits, there is a critical lack of neurocompatible and multifunctional particles described for use with transplant populations for neurological applications. Here, a systematic screen of MNPs (using a core shown to cause contrast in magnetic resonance imaging (MRI)) bearing various surface chemistries (polyethylenimine (PEI) and oxidized PEI and hybrids of oxidized PEI/alginic acid, PEI/chitosan and PEI/polyamidoamine) is performed to test their ability to genetically engineer neural stem cells (NSCs; a cell population of high clinical relevance for central nervous system disorders). It is demonstrated that gene delivery to NSCs can be safely achieved using two of the developed formulations (PEI and oxPEI/alginic acid) when used in conjunction with oscillating magnetofection technology. After transfection, intracellular particles can be detected by histological procedures with labeled cells displaying contrast in MRI (for real time cell tracking). PMID:26867130

  1. Using magnetic resonance imaging to evaluate dendritic cell-based vaccination.

    Peter M Ferguson

    Full Text Available Cancer immunotherapy with antigen-loaded dendritic cell-based vaccines can induce clinical responses in some patients, but further optimization is required to unlock the full potential of this strategy in the clinic. Optimization is dependent on being able to monitor the cellular events that take place once the dendritic cells have been injected in vivo, and to establish whether antigen-specific immune responses to the tumour have been induced. Here we describe the use of magnetic resonance imaging (MRI as a simple, non-invasive approach to evaluate vaccine success. By loading the dendritic cells with highly magnetic iron nanoparticles it is possible to assess whether the injected cells drain to the lymph nodes. It is also possible to establish whether an antigen-specific response is initiated by assessing migration of successive rounds of antigen-loaded dendritic cells; in the face of a successfully primed cytotoxic response, the bulk of antigen-loaded cells are eradicated on-route to the node, whereas cells without antigen can reach the node unchecked. It is also possible to verify the induction of a vaccine-induced response by simply monitoring increases in draining lymph node size as a consequence of vaccine-induced lymphocyte trapping, which is an antigen-specific response that becomes more pronounced with repeated vaccination. Overall, these MRI techniques can provide useful early feedback on vaccination strategies, and could also be used in decision making to select responders from non-responders early in therapy.

  2. Electrochemical cell for in situ electrodeposition of magnetic thin films in a superconducting quantum interference device magnetometer

    Topolovec, Stefan, E-mail: stefan.topolovec@tugraz.at; Würschum, Roland, E-mail: wuerschum@tugraz.at [Institute of Materials Physics, Graz University of Technology, Petersgasse 16, 8010 Graz (Austria); Krenn, Heinz [Institute of Physics, University of Graz, Universitätsplatz 5, 8010 Graz (Austria)

    2015-06-15

    An electrochemical cell is designed and applied for in situ electrodeposition of magnetic thin films in a commercial SQUID magnetometer system. The cell is constructed in such a way that any parasitic contribution of the cell and of the substrate for electrodeposition to the magnetic moment of the deposited film is reduced to a minimum. A remanent minor contribution is readily taken into account by a proper analysis of the detected signal. Thus, a precise determination of the absolute magnetic moment of the electrodeposited magnetic film during its growth and dissolution is achieved. The feasibility of the cell design is demonstrated by performing Co electrodeposition using cyclic voltammetry. For an average Co film thickness of (35.6 ± 3.0) atomic layers, a magnetic moment per Co atom of (1.75 ± 0.11) μ{sub B} was estimated, in good agreement with the literature bulk value.

  3. Electrochemical cell for in situ electrodeposition of magnetic thin films in a superconducting quantum interference device magnetometer

    An electrochemical cell is designed and applied for in situ electrodeposition of magnetic thin films in a commercial SQUID magnetometer system. The cell is constructed in such a way that any parasitic contribution of the cell and of the substrate for electrodeposition to the magnetic moment of the deposited film is reduced to a minimum. A remanent minor contribution is readily taken into account by a proper analysis of the detected signal. Thus, a precise determination of the absolute magnetic moment of the electrodeposited magnetic film during its growth and dissolution is achieved. The feasibility of the cell design is demonstrated by performing Co electrodeposition using cyclic voltammetry. For an average Co film thickness of (35.6 ± 3.0) atomic layers, a magnetic moment per Co atom of (1.75 ± 0.11) μB was estimated, in good agreement with the literature bulk value

  4. Hyperthermic potentiation of cisplatin by magnetic nanoparticle heaters is correlated with an increase in cell membrane fluidity

    Alvarez-Berrios MP

    2013-03-01

    Full Text Available Merlis P Alvarez-Berríos, Amalchi Castillo, Janet Mendéz, Orlando Soto, Carlos Rinaldi, Madeline Torres-LugoDepartment of Chemical Engineering, University of Puerto Rico, Mayagüez, Puerto RicoAbstract: Magnetic fluid hyperthermia as a cancer treatment method is an attractive alternative to other forms of hyperthermia. It is based on the heat released by magnetic nanoparticles subjected to an alternating magnetic field. Recent studies have shown that magnetic fluid hyperthermia-treated cells respond significantly better to chemotherapeutic treatment compared with cells treated with hot water hyperthermia under the same temperature conditions. We hypothesized that this synergistic effect is due to an additional stress on the cellular membrane, independent of the thermal heat dose effect that is induced by nanoparticles exposed to an alternating magnetic field. This would result in an increase in Cis-diammine-dichloroplatinum (II (cDDP, cisplatin uptake via passive transport. To test this hypothesis, we exposed cDDP-treated cells to extracellular copper in order to hinder the human cell copper transporter (hCTR1-mediated active transport of cDDP. This, in turn, can increase the passive transport of the drug through the cell membrane. Our results did not show statistically significant differences in surviving fractions for cells treated concomitantly with magnetic fluid hyperthermia and cDDP, in the presence or absence of copper. Nonetheless, significant copper-dependent variations in cell survival were observed for samples treated with combined cDDP and hot water hyperthermia. These results correlated with platinum uptake studies, which showed that cells treated with magnetic fluid hyperthermia had higher platinum uptake than cells treated with hot water hyperthermia. Changes in membrane fluidity were tested through fluorescence anisotropy measurements using trimethylamine-diphenylhexatriene. Additional uptake studies were conducted with

  5. Magnetic nanoparticles in primary neural cell cultures are mainly taken up by microglia

    Pinkernelle Josephine

    2012-03-01

    Full Text Available Abstract Background Magnetic nanoparticles (MNPs offer a large range of applications in life sciences. Applications in neurosciences are one focus of interest. Unfortunately, not all groups have access to nanoparticles or the possibility to develop and produce them for their applications. Hence, they have to focus on commercially available particles. Little is known about the uptake of nanoparticles in primary cells. Previously studies mostly reported cellular uptake in cell lines. Here we present a systematic study on the uptake of magnetic nanoparticles (MNPs by primary cells of the nervous system. Results We assessed the internalization in different cell types with confocal and electron microscopy. The analysis confirmed the uptake of MNPs in the cells, probably with endocytotic mechanisms. Furthermore, we compared the uptake in PC12 cells, a rat pheochromocytoma cell line, which is often used as a neuronal cell model, with primary neuronal cells. It was found that the percentage of PC12 cells loaded with MNPs was significantly higher than for neurons. Uptake studies in primary mixed neuronal/glial cultures revealed predominant uptake of MNPs by microglia and an increase in their number. The number of astroglia and oligodendroglia which incorporated MNPs was lower and stable. Primary mixed Schwann cell/fibroblast cultures showed similar MNP uptake of both cell types, but the Schwann cell number decreased after MNP incubation. Organotypic co-cultures of spinal cord slices and peripheral nerve grafts resembled the results of the dispersed primary cell cultures. Conclusions The commercial MNPs used activated microglial phagocytosis in both disperse and organotypic culture systems. It can be assumed that in vivo application would induce immune system reactivity, too. Because of this, their usefulness for in vivo neuroscientific implementations can be questioned. Future studies will need to overcome this issue with the use of cell

  6. MAGNET

    B. Curé

    2013-01-01

    The magnet is fully stopped and at room temperature. The maintenance works and consolidation activities on the magnet sub-systems are progressing. To consolidate the cryogenic installation, two redundant helium compressors will be installed as ‘hot spares’, to avoid the risk of a magnet downtime in case of a major failure of a compressor unit during operation. The screw compressors, their motors, the mechanical couplings and the concrete blocks are already available and stored at P5. The metallic structure used to access the existing compressors in SH5 will be modified to allow the installation of the two redundant ones. The plan is to finish the installation and commissioning of the hot spare compressors before the summer 2014. In the meantime, a bypass on the high-pressure helium piping will be installed for the connection of a helium drier unit later during the Long Shutdown 1, keeping this installation out of the schedule critical path. A proposal is now being prepared for the con...

  7. MAGNET

    Benoit Curé

    2010-01-01

    The magnet worked very well at 3.8 T as expected, despite a technical issue that manifested twice in the cryogenics since June. All the other magnet sub-systems worked without flaw. The issue in the cryogenics was with the cold box: it could be observed that the cold box was getting progressively blocked, due to some residual humidity and air accumulating in the first thermal exchanger and in the adsorber at 65 K. This was later confirmed by the analysis during the regeneration phases. An increase in the temperature difference between the helium inlet and outlet across the heat exchanger and a pressure drop increase on the filter of the adsorber were observed. The consequence was a reduction of the helium flow, first compensated by the automatic opening of the regulation valves. But once they were fully opened, the flow and refrigeration power reduced as a consequence. In such a situation, the liquid helium level in the helium Dewar decreased, eventually causing a ramp down of the magnet current and a field...

  8. MAGNET

    Benoit Curé.

    The magnet operation restarted end of June this year. Quick routine checks of the magnet sub-systems were performed at low current before starting the ramps up to higher field. It appeared clearly that the end of the field ramp down to zero was too long to be compatible with the detector commissioning and operations plans. It was decided to perform an upgrade to keep the ramp down from 3.8T to zero within 4 hours. On July 10th, when a field of 1.5T was reached, small movements were observed in the forward region support table and it was decided to fix this problem before going to higher field. At the end of July the ramps could be resumed. On July 28th, the field was at 3.8T and the summer CRAFT exercise could start. This run in August went smoothly until a general CERN wide power cut took place on August 3rd, due to an insulation fault on the high voltage network outside point 5. It affected the magnet powering electrical circuit, as it caused the opening of the main circuit breakers, resulting in a fast du...

  9. MAGNET

    B. Curé

    MAGNET During the winter shutdown, the magnet subsystems went through a full maintenance. The magnet was successfully warmed up to room temperature beginning of December 2008. The vacuum was broken later on by injecting nitrogen at a pressure just above one atmosphere inside the vacuum tank. This was necessary both to prevent any accidental humidity ingress, and to allow for a modification of the vacuum gauges on the vacuum tank and maintenance of the diffusion pumps. The vacuum gauges had to be changed, because of erratic variations on the measurements, causing spurious alarms. The new type of vacuum gauges has been used in similar conditions on the other LHC experiments and without problems. They are shielded against the stray field. The lubricants of the primary and diffusion pumps have been changed. Several minor modifications were also carried out on the equipment in the service cavern, with the aim to ease the maintenance and to allow possible intervention during operation. Spare sensors have been bough...

  10. Isolation of cells for selective treatment and analysis using a magnetic microfluidic chip

    Yassine, O.

    2014-05-01

    This study describes the development and testing of a magnetic microfluidic chip (MMC) for trapping and isolating cells tagged with superparamagnetic beads (SPBs) in a microfluidic environment for selective treatment and analysis. The trapping and isolation are done in two separate steps; first, the trapping of the tagged cells in a main channel is achieved by soft ferromagnetic disks and second, the transportation of the cells into side chambers for isolation is executed by tapered conductive paths made of Gold (Au). Numerical simulations were performed to analyze the magnetic flux and force distributions of the disks and conducting paths, for trapping and transporting SPBs. The MMC was fabricated using standard microfabrication processes. Experiments were performed with E. coli (K12 strand) tagged with 2.8 μm SPBs. The results showed that E. coli can be separated from a sample solution by trapping them at the disk sites, and then isolated into chambers by transporting them along the tapered conducting paths. Once the E. coli was trapped inside the side chambers, two selective treatments were performed. In one chamber, a solution with minimal nutrition content was added and, in another chamber, a solution with essential nutrition was added. The results showed that the growth of bacteria cultured in the second chamber containing nutrient was significantly higher, demonstrating that the E. coli was not affected by the magnetically driven transportation and the feasibility of performing different treatments on selectively isolated cells on a single microfluidic platform.

  11. Expression of Heat Shock Proteins in Human Fibroblast Cells under Magnetic Resonant Coupling Wireless Power Transfer

    Kohei Mizuno

    2015-10-01

    Full Text Available Since 2007, resonant coupling wireless power transfer (WPT technology has been attracting attention and has been widely researched for practical use. Moreover, dosimetric evaluation has also been discussed to evaluate the potential health risks of the electromagnetic field from this WPT technology based on the International Commission on Non-Ionizing Radiation Protection (ICNIRP guidelines. However, there has not been much experimental evaluation of the potential health risks of this WPT technology. In this study, to evaluate whether magnetic resonant coupling WPT induces cellular stress, we focused on heat shock proteins (Hsps and determined the expression level of Hsps 27, 70 and 90 in WI38VA13 subcloned 2RA human fibroblast cells using a western blotting method. The expression level of Hsps under conditions of magnetic resonant coupling WPT for 24 h was not significantly different compared with control cells, although the expression level of Hsps for cells exposed to heat stress conditions was significantly increased. These results suggested that exposure to magnetic resonant coupling WPT did not cause detectable cell stress.

  12. Size-Dependent Photodynamic Anticancer Activity of Biocompatible Multifunctional Magnetic Submicron Particles in Prostate Cancer Cells.

    Choi, Kyong-Hoon; Nam, Ki Chang; Malkinski, Leszek; Choi, Eun Ha; Jung, Jin-Seung; Park, Bong Joo

    2016-01-01

    In this study, newly designed biocompatible multifunctional magnetic submicron particles (CoFe₂O₄-HPs-FAs) of well-defined sizes (60, 133, 245, and 335 nm) were fabricated for application as a photosensitizer delivery agent for photodynamic therapy in cancer cells. To provide selective targeting of cancer cells and destruction of cancer cell functionality, basic cobalt ferrite (CoFe₂O₄) particles were covalently bonded with a photosensitizer (PS), which comprises hematoporphyrin (HP), and folic acid (FA) molecules. The magnetic properties of the CoFe₂O₄ particles were finely adjusted by controlling the size of the primary CoFe₂O₄ nanograins, and secondary superstructured composite particles were formed by aggregation of the nanograins. The prepared CoFe₂O₄-HP-FA exhibited high water solubility, good MR-imaging capacity, and biocompatibility without any in vitro cytotoxicity. In particular, our CoFe₂O₄-HP-FA exhibited remarkable photodynamic anticancer efficiency via induction of apoptotic death in PC-3 prostate cancer cells in a particle size- and concentration-dependent manner. This size-dependent effect was determined by the specific surface area of the particles because the number of HP molecules increased with decreasing size and increasing surface area. These results indicate that our CoFe₂O₄-HP-FA may be applicable for photodynamic therapy (PDT) as a PS delivery material and a therapeutic agent for MR-imaging based PDT owing to their high saturation value for magnetization and superparamagnetism. PMID:27607999

  13. Dual-Color Fluorescence Imaging of Magnetic Nanoparticles in Live Cancer Cells Using Conjugated Polymer Probes.

    Sun, Minjie; Sun, Bin; Liu, Yun; Shen, Qun-Dong; Jiang, Shaojun

    2016-01-01

    Rapid growth in biological applications of nanomaterials brings about pressing needs for exploring nanomaterial-cell interactions. Cationic blue-emissive and anionic green-emissive conjugated polymers are applied as dual-color fluorescence probes to the surface of negatively charged magnetic nanoparticles through sequentially electrostatic adsorption. These conjugated polymers have large extinction coefficients and high fluorescence quantum yield (82% for PFN and 62% for ThPFS). Thereby, one can visualize trace amount (2.7 μg/mL) of fluorescence-labeled nanoparticles within cancer cells by confocal laser scanning microscopy. Fluorescence labeling by the conjugated polymers is also validated for quantitative determination of the internalized nanoparticles in each individual cell by flow cytometry analysis. Extensive overlap of blue and green fluorescence signals in the cytoplasm indicates that both conjugated polymer probes tightly bind to the surface of the nanoparticles during cellular internalization. The highly charged and fluorescence-labeled nanoparticles non-specifically bind to the cell membranes, followed by cellular uptake through endocytosis. The nanoparticles form aggregates inside endosomes, which yields a punctuated staining pattern. Cellular internalization of the nanoparticles is dependent on the dosage and time. Uptake efficiency can be enhanced three-fold by application of an external magnetic field. The nanoparticles are low cytotoxicity and suitable for simultaneously noninvasive fluorescence and magnetic resonance imaging application. PMID:26931282

  14. Electric cell voltage at etching and deposition of metals under an inhomogeneous constant magnetic field

    O.Yu. Gorobets

    2014-12-01

    Full Text Available The self-organized electric cell voltage of the physical circuit is calculated at etching and deposition of metals at the surface of a magnetized ferromagnetic electrode in an electrolyte without passing an external electrical current. This self-organized voltage arises due to the inhomogeneous distribution of concentration of the effectively dia- or paramagnetic cluster components of an electrolyte at the surface of a ferromagnetic electrode under the effect of inhomogeneous magnetostatic fields. The current density and Lorentz force are calculated in an electrolyte in the vicinity of the magnetized steel ball-shaped electrode. The Lorentz force causes the rotation of an electrolyte around the direction of an external magnetic field.

  15. Magnetic resonance imaging findings in giant cell arteritis.

    D'Souza, N M; Morgan, M L; Almarzouqi, S J; Lee, A G

    2016-05-01

    PurposeGiant cell arteritis (GCA) is a systemic vasculitis that affects medium-to-large-caliber arteries. Early diagnosis and treatment is essential as involvement of the ophthalmic artery or its branches may cause blindness. Radiographic findings may be variable and non-specific leading to delay in diagnosis. We conducted a review of the literature on neuroimaging findings in GCA and present a retrospective case series from tertiary-care ophthalmic referral centers of three patients with significant neuroimaging findings in biopsy-proven GCA.MethodsRetrospective case series of biopsy-proven GCA cases with neuroimaging findings at the Department of Ophthalmology, Blanton Eye Institute, Houston Methodist Hospital between 2010-2015 were included in this study. Literature search was conducted using Google Scholar and Medline search engines between the years 1970 and 2015.ResultsWe report findings of optic nerve enhancement, optic nerve sheath enhancement, and the first description in the English-language ophthalmic literature, to our knowledge, of chiasmal enhancement in biopsy-proven GCA. We describe four main categories of neuroimaging findings that may be seen in GCA from our series and from past cases in the literature.DiscussionIt is essential that clinicians be aware of the possible radiographic findings in GCA. Appropriate and prompt treatment should not be delayed based upon these findings. PMID:26915748

  16. Antibody-free magnetic cell sorting of genetically modified primary human CD4+ T cells by one-step streptavidin affinity purification.

    Nicholas J Matheson

    Full Text Available Existing methods for phenotypic selection of genetically modified mammalian cells suffer disadvantages of time, cost and scalability and, where antibodies are used to bind exogenous cell surface markers for magnetic selection, typically yield cells coated with antibody-antigen complexes and beads. To overcome these limitations we have developed a method termed Antibody-Free Magnetic Cell Sorting in which the 38 amino acid Streptavidin Binding Peptide (SBP is displayed at the cell surface by the truncated Low Affinity Nerve Growth Receptor (LNGFRF and used as an affinity tag for one-step selection with streptavidin-conjugated magnetic beads. Cells are released through competition with the naturally occurring vitamin biotin, free of either beads or antibody-antigen complexes and ready for culture or use in downstream applications. Antibody-Free Magnetic Cell Sorting is a rapid, cost-effective, scalable method of magnetic selection applicable to either viral transduction or transient transfection of cell lines or primary cells. We have optimised the system for enrichment of primary human CD4+ T cells expressing shRNAs and exogenous genes of interest to purities of >99%, and used it to isolate cells following Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR/Cas9 genome editing.

  17. Antibody-Free Magnetic Cell Sorting of Genetically Modified Primary Human CD4+ T Cells by One-Step Streptavidin Affinity Purification

    Matheson, Nicholas J.; Peden, Andrew A.; Lehner, Paul J.

    2014-01-01

    Existing methods for phenotypic selection of genetically modified mammalian cells suffer disadvantages of time, cost and scalability and, where antibodies are used to bind exogenous cell surface markers for magnetic selection, typically yield cells coated with antibody-antigen complexes and beads. To overcome these limitations we have developed a method termed Antibody-Free Magnetic Cell Sorting in which the 38 amino acid Streptavidin Binding Peptide (SBP) is displayed at the cell surface by the truncated Low Affinity Nerve Growth Receptor (LNGFRF) and used as an affinity tag for one-step selection with streptavidin-conjugated magnetic beads. Cells are released through competition with the naturally occurring vitamin biotin, free of either beads or antibody-antigen complexes and ready for culture or use in downstream applications. Antibody-Free Magnetic Cell Sorting is a rapid, cost-effective, scalable method of magnetic selection applicable to either viral transduction or transient transfection of cell lines or primary cells. We have optimised the system for enrichment of primary human CD4+ T cells expressing shRNAs and exogenous genes of interest to purities of >99%, and used it to isolate cells following Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 genome editing. PMID:25360777

  18. Multifunctional nanoprobe for cancer cell targeting and simultaneous fluorescence/magnetic resonance imaging.

    Wei, Zhenzhen; Wu, Yafeng; Zhao, Yuewu; Mi, Li; Wang, Jintao; Wang, Jimin; Zhao, Jinjin; Wang, Lixin; Liu, Anran; Li, Ying; Wei, Wei; Zhang, Yuanjian; Liu, Songqin

    2016-09-28

    Multifunctional nanoprobes with distinctive magnetic and fluorescent properties are highly useful in accurate and early cancer diagnosis. In this study, nanoparticles of Fe3O4 core with fluorescent SiO2 shell (MFS) are synthesized by a facile improved Stöber method. These nanoparticles owning a significant core-shell structure exhibit good dispersion, stable fluorescence, low cytotoxicity and excellent biocompatibility. TLS11a aptamer (Apt1), a specific membrane protein for human liver cancer cells which could be internalized into cells, is conjugated to the MFS nanoparticles through the formation of amide bond working as a target-specific moiety. The attached TLS11a aptamers on nanoparticles are very stable and can't be hydrolyzed by DNA hydrolytic enzyme in vivo. Both fluorescence and magnetic resonance imaging show significant uptake of aptamer conjugated nanoprobe by HepG2 cells compared to 4T1, SGC-7901 and MCF-7 cells. In addition, with the increasing concentration of the nanoprobe, T2-weighted MRI images of the as-treated HepG2 cells are significantly negatively enhanced, indicating that a high magnetic field gradient is generated by MFS-Apt1 which has been specifically captured by HepG2 cells. The relaxivity of nanoprobe is calculated to be 11.5 mg(-1)s(-1). The MR imaging of tumor-bearing nude mouse is also confirmed. The proposed multifunctional nanoprobe with the size of sub-100 nm has the potential to provide real-time imaging in early liver cancer cell diagnosis. PMID:27619098

  19. Mesenchymal stem cell in vitro labeling by hybrid fluorescent magnetic polymeric particles for application in cell tracking.

    Supokawej, Aungkura; Nimsanor, Natakarn; Sanvoranart, Tanwarat; Kaewsaneha, Chariya; Hongeng, Suradej; Tangboriboonrat, Pramuan; Jangpatarapongsa, Kulachart

    2015-12-01

    Mesenchymal stem cells (MSCs) are a type of adult stem cell that contains multi-differentiation and proliferative properties and that shows high treatment implications for many clinical problems. The outcome of stem cell transplantation is still limited due to many factors, especially their survival and their interaction with the microenvironment after transplantation. Molecular imaging is a challenging technique that has been used to overcome this limitation and is based on the concept of labeling cells with tractable, visible, and non-toxic materials to track the cells after transplantation. In this study, magnetic polymeric nanoparticles (MPNPs) were used to directly label Wharton's jelly-derived MSCs (WJ-MSCs). After labeling, the growth rate and the viability of the MSCs as well as the time of exposure were determined. The 3D images of WJ-MSCs labeled with MPNPs for 24 h were created using confocal microscopy. The results showed that, after incubation with fluorescent MPNPs for over 8 h, the growth rate and cell viability of the WJ-MSCs was similar to those of the control. Three-dimensional imaging revealed that the fluorescent MPNPs could infiltrate into the cells and spread into the cytoplasm, which suggests that the synthesized fluorescent MPNPs could possibly label MSCs for cell tracking study and be further developed for in vivo applications. PMID:25893425

  20. A smart fully integrated micromachined separator with soft magnetic micro-pillar arrays for cell isolation

    Dong, Tao; Su, Qianhua; Yang, Zhaochu; Zhang, Yulong; Egeland, Eirik B.; Gu, Dan D.; Calabrese, Paolo; Kapiris, Matteo J.; Karlsen, Frank; Minh, Nhut T.; Wang, K.; Jakobsen, Henrik

    2010-11-01

    A smart fully integrated micromachined separator with soft magnetic micro-pillar arrays has been developed and demonstrated, which can merely employ one independent lab-on-chip to realize cell isolation. The simulation, design, microfabrication and test for the new electromagnetic micro separator were executed. The simulation results of the electromagnetic field in the separator show that special soft magnetic micro-pillar arrays can amplify and redistribute the electromagnetic field generated by the micro-coils. The separator can be equipped with a strong magnetic field to isolate the target cells with a considerably low input current. The micro separator was fabricated by micro-processing technology. An electroplating bath was hired to deposit NiCo/NiFe to fabricate the micro-pillar arrays. An experimental system was set up to verify the function of the micro separator by isolating the lymphocytes, in which the human whole blood mixed with Dynabeads® FlowComp Flexi and monoclonal antibody MHCD2704 was used as the sample. The results show that the electromagnetic micro separator with an extremely low input current can recognize and capture the target lymphocytes with a high efficiency, the separation ratio reaching more than 90% at a lower flow rate. For the electromagnetic micro separator, there is no external magnetizing field required, and there is no extra cooling system because there is less Joule heat generated due to the lower current. The magnetic separator is totally reusable, and it can be used to separate cells or proteins with common antigens.

  1. The effect of cryoprotection on the use of PLGA encapsulated iron oxide nanoparticles for magnetic cell labeling

    Magnetic PLGA nanoparticles are a significant advancement in the quest to translate MRI-based cell tracking to the clinic. The benefits of these types of particles are that they encapsulate large amounts of iron oxide nanocrystals within an FDA-approved polymer matrix, combining the best aspects of inert micron-sized iron oxide particles, or MPIOs, and biodegradable small particles of iron oxide, or SPIOs. Practically, PLGA nanoparticle fabrication and storage requires some form of cryoprotectant to both protect the particle during freeze drying and to promote resuspension. While this is a commonly employed procedure in the fabrication of drug loaded PLGA nanoparticles, it has yet to be investigated for magnetic particles and what effect this might have on internalization of magnetic particles. As such, in this study, magnetic PLGA nanoparticles were fabricated with various concentrations of two common cryoprotectants, dextrose and sucrose, and analyzed for their ability to magnetically label cells. It was found that cryoprotection with either sugar significantly enhanced the ability to resuspend nanoparticles without aggregation. Magnetic cell labeling was impacted by sugar concentration, with higher sugar concentrations used during freeze drying more significantly reducing magnetic cell labeling than lower concentrations. These studies suggest that cryoprotection with 1% dextrose is an optimal compromise that preserves monodispersity following resuspension and high magnetic cell labeling. (paper)

  2. The effect of cryoprotection on the use of PLGA encapsulated iron oxide nanoparticles for magnetic cell labeling

    Tang, Kevin S.; Hashmi, Sarah M.; Shapiro, Erik M.

    2013-03-01

    Magnetic PLGA nanoparticles are a significant advancement in the quest to translate MRI-based cell tracking to the clinic. The benefits of these types of particles are that they encapsulate large amounts of iron oxide nanocrystals within an FDA-approved polymer matrix, combining the best aspects of inert micron-sized iron oxide particles, or MPIOs, and biodegradable small particles of iron oxide, or SPIOs. Practically, PLGA nanoparticle fabrication and storage requires some form of cryoprotectant to both protect the particle during freeze drying and to promote resuspension. While this is a commonly employed procedure in the fabrication of drug loaded PLGA nanoparticles, it has yet to be investigated for magnetic particles and what effect this might have on internalization of magnetic particles. As such, in this study, magnetic PLGA nanoparticles were fabricated with various concentrations of two common cryoprotectants, dextrose and sucrose, and analyzed for their ability to magnetically label cells. It was found that cryoprotection with either sugar significantly enhanced the ability to resuspend nanoparticles without aggregation. Magnetic cell labeling was impacted by sugar concentration, with higher sugar concentrations used during freeze drying more significantly reducing magnetic cell labeling than lower concentrations. These studies suggest that cryoprotection with 1% dextrose is an optimal compromise that preserves monodispersity following resuspension and high magnetic cell labeling.

  3. Modular design for narrow scintillating cells with MRS photodiodes in strong magnetic field for ILC detector

    Beznosko, D.; Blazey, G.; Dyshkant, A.; Rykalin, V.; Schellpffer, J.; Zutshi, V.

    2006-08-01

    The experimental results for the narrow scintillating elements with effective area about 20 cm 2 are reported. The elements were formed from the single piece of scintillator and were read out via wavelength shifting (WLS) fibers with the Metal/Resistor/Semiconductor (MRS) photodiodes on both ends of each fiber. The count rates were obtained using radioactive source 90Sr, with threshold at about three photoelectrons in each channel and quad coincidences (double coincidences between sensors on each fiber and double coincidences between two neighboring fibers). The formation of the cells from the piece of scintillator by using grooves is discussed, and their performances were tested using the radioactive source by measuring the photomutiplier current using the same WLS fiber. Because effective cell area can be readily enlarged or reduced, this module may be used as an active element for calorimeter or muon system for the design of the future electron-positron linear collider detector. Experimental verification of the performance of the MRS photodiode in a strong magnetic field of 9 T, and the impact a magnet quench at 9.5 T are reported. The measurement method used is described. The results confirm the expectations that the MRS photodiode is insensitive to a strong magnetic field and therefore applicable to calorimetry in the presence of magnetic field. The overall result is of high importance for large multi-channel systems.

  4. Effects of Static Magnetic Field on Growth of Leptospire, Leptospira interrogans serovar canicola: Immunoreactivity and Cell Division

    Triampo, W; Triampo, D; Wong-Ekkabut, J; Tang, I M; Triampo, Wannapong; Doungchawee, Galayanee; Triampo, Darapond; Wong-Ekkabut, Jirasak

    2004-01-01

    The effects of the exposure of the bacterium, Leptospira interrogans serovar canicola to a constant magnetic field with magnetic flux density from a permanent ferrite magnet = 140 mT were studied. Changes in Leptospira cells after their exposure to the field were determined on the basis of changes in their growth behavior and agglutination immunoreactivity with a homologous antiserum using darkfield microscopy together with visual imaging. The data showed that the exposed Leptospira cells have lower densities and lower agglutination immunoreactivity than the unexposed control group. Interestingly, some of the exposed Leptospira cells showed abnormal morphologies such as large lengths. We discussed some of the possible reasons for these observations.

  5. In vitro studies of magnetically enhanced transfection in COS-7 cells

    Ang, D.; Tay, C.Y.; Tan, L.P. [School of Materials Science and Engineering, Nanyang Technological University (Singapore); Preiser, P.R. [School of Biological Sciences, Nanyang Technological University (Singapore); Ramanujan, R.V., E-mail: Ramanujan@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University (Singapore)

    2011-10-10

    In the magnetically enhanced gene delivery technique, DNA complexed with polymer coated aggregated magnetic nanoparticles (AMNPs) is used for effecting transfection. The aim of this study is to examine the relationship between transfection efficiency and the physical characteristics of the polymer coated AMNPs. In vitro studies of transfection efficiency in COS-7 cells were carried out using pEGFP-N1 and pMIR-REPORT complexed polyethylenimine (PEI) coated iron oxide magnetic nanoparticles. PEI coated AMNPs (PEI-AMNPs) with average individual particle diameters in the range of 8 nm to 30 nm were studied and characterized by transmission electron microscopy, vibrating sample magnetometry, X-ray diffractometry, thermal gravimetric analysis and photon correlation spectroscopy methods. PEI-A8MNP and PEI-A30MNP yielded higher transfection efficiency compared to commercial polyMAG particles as well as PEI of equivalent molar ratio of nitrogen/phosphorous (N/P ratio). The transfection efficiency was related to the physical characteristics of the PEI-AMNPs and its complexes: transfection efficiency was strongly positively correlated with saturation magnetization (Ms) and susceptibility ({chi}), strongly negatively correlated with N/P ratio, moderately positively correlated to zeta potential and moderately negatively correlated to hydrodynamic diameter of the complex. PEI-A8MNP and PEI-A30MNP possessing higher Ms, {chi}, lower N/P ratio and smaller complex size exhibited higher transfection efficiency compared to PEI-A16MNP which have weaker magnetic properties, higher N/P ratio and larger complex size. We have demonstrated that optimization of the physical properties of PEI-AMNPs is needed to maximize transfection efficiency. - Research highlights: {yields}The transfection efficiency in magnetically enhanced gene delivery was studied. {yields}Transfection efficiency was strongly positively correlated to magnetic properties. {yields}Transfection efficiency was strongly

  6. In vitro studies of magnetically enhanced transfection in COS-7 cells

    In the magnetically enhanced gene delivery technique, DNA complexed with polymer coated aggregated magnetic nanoparticles (AMNPs) is used for effecting transfection. The aim of this study is to examine the relationship between transfection efficiency and the physical characteristics of the polymer coated AMNPs. In vitro studies of transfection efficiency in COS-7 cells were carried out using pEGFP-N1 and pMIR-REPORT complexed polyethylenimine (PEI) coated iron oxide magnetic nanoparticles. PEI coated AMNPs (PEI-AMNPs) with average individual particle diameters in the range of 8 nm to 30 nm were studied and characterized by transmission electron microscopy, vibrating sample magnetometry, X-ray diffractometry, thermal gravimetric analysis and photon correlation spectroscopy methods. PEI-A8MNP and PEI-A30MNP yielded higher transfection efficiency compared to commercial polyMAG particles as well as PEI of equivalent molar ratio of nitrogen/phosphorous (N/P ratio). The transfection efficiency was related to the physical characteristics of the PEI-AMNPs and its complexes: transfection efficiency was strongly positively correlated with saturation magnetization (Ms) and susceptibility (χ), strongly negatively correlated with N/P ratio, moderately positively correlated to zeta potential and moderately negatively correlated to hydrodynamic diameter of the complex. PEI-A8MNP and PEI-A30MNP possessing higher Ms, χ, lower N/P ratio and smaller complex size exhibited higher transfection efficiency compared to PEI-A16MNP which have weaker magnetic properties, higher N/P ratio and larger complex size. We have demonstrated that optimization of the physical properties of PEI-AMNPs is needed to maximize transfection efficiency. - Research highlights: →The transfection efficiency in magnetically enhanced gene delivery was studied. →Transfection efficiency was strongly positively correlated to magnetic properties. →Transfection efficiency was strongly negatively correlated with

  7. The Effect of Iron Oxide Magnetic Nanoparticles on Smooth Muscle Cells

    Zhang, Song; Chen, Xiangjian; Gu, Chunrong; Zhang, Yu; Xu, Jindan; Bian, Zhiping; Yang, Di; Gu, Ning

    2009-01-01

    Recently, magnetic nanoparticles of iron oxide (Fe3O4, γ-Fe2O3) have shown an increasing number of applications in the field of biomedicine, but some questions have been raised about the potential impact of these nanoparticles on the environment and human health. In this work, the three types of magnetic nanoparticles (DMSA-Fe2O3, APTS-Fe2O3, and GLU-Fe2O3) with the same crystal structure, magnetic properties, and size distribution was designed, prepared, and characterized by transmission electronic microscopy, powder X-ray diffraction, zeta potential analyzer, vibrating sample magnetometer, and Fourier transform Infrared spectroscopy. Then, we have investigated the effect of the three types of magnetic nanoparticles (DMSA-Fe2O3, APTS-Fe2O3, and GLU-Fe2O3) on smooth muscle cells (SMCs). Cellular uptake of nanoparticles by SMC displays the dose, the incubation time and surface property dependent patterns. Through the thin section TEM images, we observe that DMSA-Fe2O3 is incorporated into the lysosome of SMCs. The magnetic nanoparticles have no inflammation impact, but decrease the viability of SMCs. The other questions about metabolism and other impacts will be the next subject of further studies.

  8. Imaging characteristics of papillary renal cell carcinoma by computed tomography scan and magnetic resonance imaging

    The aim of this study was to analyse the differences in the patterns between clear and papillary renal cell carcinomas using magnetic resonance imaging (MRI) and dual-phase helical computed tomography (CT). We examined seven patients with papillary renal cell carcinoma, and six with clear cell carcinoma. The highest attenuation value of tumors in the corticomedullary phase (CMP) and the excretory phase (EP) was measured using the observer-defined region of interest (ROI). MRI consisted of T1-weighted and T2-weighted spin-echo imaging. All five tumors except for one with papillary renal cell carcinoma showed homogenous hypointensity, but all six tumors with clear cell carcinoma showed heterogeneous hyperintensity on their T2-weighted images. In the CMP, the mean CT numbers of the papillary renal cell carcinomas were significantly lower than those of the clear cell carcinomas. The mean enhancement of the papillary renal cell carcinomas in the CMP and the EP was significantly lower than that of the clear renal cell carcinomas. The mean CT numbers of the clear cell carcinomas in the CMP were markedly increased from those on the unenhanced CT; those in the EP were decreased gradually. But the mean CT numbers of the papillary renal cell carcinomas in the EP were still slightly more increased than those in the CMP. The enhancement patterns of the papillary renal cell carcinomas in the CMP and the EP were homogenous, but those of the clear cell carcinomas were heterogeneous. We can speculate the differential diagnosis from clear to papillary renal cell carcinoma using MRI and dual-phase helical CT. (author)

  9. Multifunctional magnetic-hollow gold nanospheres for bimodal cancer cell imaging and photothermal therapy

    Bai, Ling-Yu; Yang, Xiao-Quan; An, Jie; Zhang, Lin; Zhao, Kai; Qin, Meng-Yao; Fang, Bi-Yun; Li, Cheng; Xuan, Yang; Zhang, Xiao-Shuai; Zhao, Yuan-Di; Ma, Zhi-Ya

    2015-08-01

    Multifunctional nanocomposites combining imaging and therapeutic functions have great potential for cancer diagnosis and therapy. In this work, we developed a novel theranostic agent based on hollow gold nanospheres (HGNs) and superparamagnetic iron oxide nanoparticles (SPIO). Taking advantage of the excellent magnetic properties of SPIO and strong near-infrared (NIR) absorption property of HGNs, such nanocomposites were applied to targeted magnetic resonance imaging (MRI) and photoacoustic imaging (PAI) of cancer cells. In vitro results demonstrated they displayed significant contrast enhancement for T2-weighted MRI and strong PAI signal enhancement. Simultaneously, the nanocomposites exhibited a high photothermal effect under the irradiation of the near-infrared laser and can be used as efficient photothermal therapy (PTT) agents for selective killing of cancer cells. All these results indicated that such nanocomposites combined with MRI-PAI and PTT functionality can have great potential for effective cancer diagnosis and therapy.

  10. Cell culture device and microchamber which can be monitored using nuclear magnetic resonance

    Celda-Muñoz, Bernardo; Esteve-Moya, Vicent; Sancho-Bielsa, Francisco; Villa Sanz, Rosa; Fernández Ledesma, Luis José; Berganzo Ruiz, Javier

    2010-01-01

    [EN] The invention relates to a cell culture device and microchamber which can be monitored using nuclear magnetic resonance and other imaging techniques, in which the culture microchamber is encapsulated and housed inside a chip. The microchamber and the device are easy for the user to handle, allowing same to be handled or repositioned without requiring complex mounting operations. In addition, the invention allows cultures to be studied for long periods, great...

  11. Estimation of localized current anomalies in polymer electrolyte fuel cells from magnetic flux density measurements

    Nara, Takaaki; Koike, Masanori; Ando, Shigeru; Gotoh, Yuji; Izumi, Masaaki

    2016-05-01

    In this paper, we propose novel inversion methods to estimate defects or localized current anomalies in membrane electrode assemblies (MEAs) in polymer electrolyte fuel cells (PEFCs). One method is an imaging approach with L1-norm regularization that is suitable for estimation of focal anomalies compared to Tikhonov regularization. The second is a complex analysis based method in which multiple pointwise current anomalies can be identified directly and algebraically from the measured magnetic flux density.

  12. Electric cell voltage at etching and deposition of metals under an inhomogeneous constant magnetic field

    O.Yu. Gorobets; Gorobets, Yu.I.; Rospotniuk, V. P.; Legenkiy, Yu. A.

    2015-01-01

    The self-organized electric cell voltage of the physical circuit is calculated at etching and deposition of metals at the surface of a magnetized ferromagnetic electrode in an electrolyte without passing an external electrical current. This self-organized voltage arises due to the inhomogeneous distribution of concentration of the effectively dia- or paramagnetic cluster components of an electrolyte at the surface of a ferromagnetic electrode under the effect of inhomogeneous magnetostatic fi...

  13. Motion and Magnetic Flux Changes of Coronal Bright Points Relative to Supergranular Cell Boundaries

    Yousefzadeh, M.; Safari, H.; Attie, R.; Alipour, N.

    2016-01-01

    To calculate the magnetic flux and the horizontal movement of coronal bright points (CBPs) in relation to supergranular cell boundaries, the time series of the SDO/HMI visible-light continuum images and SDO/AIA EUV images for 13 February 2011 have been studied. The supergranular lanes were detected in HMI continuum images using the automatic supergranular cell recognition method. The automatic identification and tracking method was applied for detecting the CBPs in AIA 193 Å images. By applying the ball-tracking method on HMI continuum images, the underlying flow fields were determined. By using the velocity fields and the automatic supergranular cell recognition method, the lanes and boundaries were detected. The locations of CBPs were projected on the photospheric co-spatial and co-temporal images. We found that about 90 % of the locations of CBPs correspond to the lane of the supergranular cell boundaries (network CBPs or NCBPs) of which about 40 % of them appeared at junctions. The remaining 10 % appeared within the supergranular regions (internetwork CBPs or INCBPs). The horizontal velocities for NCBPs and INCBPs were about 1.6±0.1 km s^{-1} and 1.7±0.1 km s^{-1}, respectively. Using the magnetic field extrapolation, we were able to detect the bipoles underlying CBPs, and we studied their magnetic evolution. The orientation of CBPs observed in the 171, 193, and 211 Å images and the orientation of their magnetic bipoles are positively correlated. For out of 50 INCBPs, 54 % showed cancellation, 32 % emergence, and 12 % complex flux changes. Out of 90 NCBPs, 60 % presented cancellation, 20 % showed emergence, and 20 % showed complex flux changes.

  14. Application in the Ethanol Fermentation of Immobilized Yeast Cells in Matrix of Alginate/Magnetic Nanoparticles, on Chitosan-Magnetite Microparticles and Cellulose-coated Magnetic Nanoparticles

    Ivanova, Viara; Hristov, Jordan

    2011-01-01

    Saccharomyces cerevisiae cells were entrapped in matrix of alginate and magnetic nanoparticles and covalently immobilized on magnetite-containing chitosan and cellulose-coated magnetic nanoparticles. Cellulose-coated magnetic nanoparticles with covalently immobilized thermostable {\\alpha}-amylase and chitosan particles with immobilized glucoamylase were also prepared. The immobilized cells and enzymes were applied in column reactors - 1/for simultaneous corn starch saccharification with the immobilized glucoamylase and production of ethanol with the entrapped or covalently immobilized yeast cells, 2/ for separate ethanol fermentation of the starch hydrolysates with the fixed yeasts. Hydrolysis of corn starch with the immobilized {\\alpha}-amylase and glucoamylase, and separate hydrolysis with the immobilized {\\alpha}-amylase were also examined. In the first reactor the ethanol yield reached approx. 91% of the theoretical; the yield was approx. 86% in the second. The ethanol fermentation was affected by the typ...

  15. Model experiments for immunomagnetic elimination of leukemic cells from human bone marrow. Presentation of a novel magnetic separation system.

    Gruhn, B; Häfer, R; Müller, A; Andrä, W; Danan, H; Zintl, F

    1991-11-01

    Optimal conditions for removing leukemic cells from human bone marrow with monoclonal antibodies (mAb) and magnetic immunobeads were investigated. Monodisperse 3 microns polystyrene microspheres containing magnetite were coated with affinity-purified rabbit antimouse IgG at 4 degrees C, pH 9.6 for 18 h. SKW-3 cells (T-CLL cell line) were marked with the supravital DNA stain Hoechst 33342, seeded into normal human bone marrow, and then incubated with the mAb CD1, CD6, and CD8 at 4 degrees C for 30 min. In preliminary experiments REH cells (cALL cells) and mouse anti-REH cell antibodies were used to find the most favorable conditions for the binding of magnetic beads to tumor cells. Optimal formation of cell-bead rosettes was achieved by rotating beads and tumor cells together at room temperature at a concentration of 1 x 10(7) cells/ml, a bead: tumor cell ratio of 100:1 and an incubation time of one hour. The novel magnetic separation apparatus consists of three polystyrene chambers connected by silicone rubber tubing. The chambers contain four steel inserts each equipped with 32 nickel wires, which are magnetized by permanent magnets in such a way that the inhomogeneous high gradient magnetic field could be established within the cell suspension containing the cells to be depleted. The fluid flow was established by a peristaltic pump. At a flow rate of 1.5 ml/min and a field strength of 160 kA/m, no beads could be detected in the purged marrow. A cocktail of the three mAb was more effective than any single antibody in forming bead-cell rosettes. Two sequential purging cycles were superior to one. The marrow recovered was highly viable as assessed by trypan blue dye exclusion and by growth of CFU-GM. PMID:1786986

  16. Nitric oxide releasing iron oxide magnetic nanoparticles for biomedical applications: cell viability, apoptosis and cell death evaluations

    Nitric oxide (NO) is involved in several physiological and pathophysiological processes, such as control of vascular tone and immune responses against microbes. Thus, there is great interest in the development of NO-releasing materials to carry and deliver NO for biomedical applications. Magnetic iron oxide nanoparticles have been used in important pharmacological applications, including drug-delivery. In this work, magnetic iron oxide nanoparticles were coated with thiol-containing hydrophilic ligands: mercaptosuccinic acid (MSA) and dimercaptosuccinic acid (DMSA). Free thiol groups on the surface of MSA- or DMSA- coated nanoparticles were nitrosated, leading to the formation of NO-releasing iron oxide nanoparticles. The cytotoxicity of MSA- or DMSA-coated magnetic nanoparticles (MNP) (thiolated nanoparticles) and nitrosated MSA- or nitrosated DMSA- coated MNPs (NO-releasing nanoparticles) were evaluated towards human lymphocytes. The results showed that MNP-MSA and MNP-DMSA have low cytotoxicity effects. On the other hand, NO-releasing MNPs were found to increase apoptosis and cell death compared to free NO-nanoparticles. Therefore, the cytotoxicity effects observed for NO-releasing MNPs may result in important biomedical applications, such as the treatment of tumors cells.

  17. Microfluidic sorting and multimodal typing of cancer cells in self-assembled magnetic arrays

    Saliba, Antoine-Emmanuel; Saias, Laure; Psychari, Eleni; Minc, Nicolas; Simon, Damien; Bidard, François-Clément; Mathiot, Claire; Pierga, Jean-Yves; Fraisier, Vincent; Salamero, Jean; Saada, Véronique; Farace, Françoise; Vielh, Philippe; Malaquin, Laurent; Viovy, Jean-Louis

    2010-01-01

    We propose a unique method for cell sorting, “Ephesia,” using columns of biofunctionalized superparamagnetic beads self-assembled in a microfluidic channel onto an array of magnetic traps prepared by microcontact printing. It combines the advantages of microfluidic cell sorting, notably the application of a well controlled, flow-activated interaction between cells and beads, and those of immunomagnetic sorting, notably the use of batch-prepared, well characterized antibody-bearing beads. On cell lines mixtures, we demonstrated a capture yield better than 94%, and the possibility to cultivate in situ the captured cells. A second series of experiments involved clinical samples—blood, pleural effusion, and fine needle aspirates— issued from healthy donors and patients with B-cell hematological malignant tumors (leukemia and lymphoma). The immunophenotype and morphology of B-lymphocytes were analyzed directly in the microfluidic chamber, and compared with conventional flow cytometry and visual cytology data, in a blind test. Immunophenotyping results using Ephesia were fully consistent with those obtained by flow cytometry. We obtained in situ high resolution confocal three-dimensional images of the cell nuclei, showing intranuclear details consistent with conventional cytological staining. Ephesia thus provides a powerful approach to cell capture and typing allowing fully automated high resolution and quantitative immunophenotyping and morphological analysis. It requires at least 10 times smaller sample volume and cell numbers than cytometry, potentially increasing the range of indications and the success rate of microbiopsy-based diagnosis, and reducing analysis time and cost. PMID:20679245

  18. Microfluidic sorting and multimodal typing of cancer cells in self-assembled magnetic arrays.

    Saliba, Antoine-Emmanuel; Saias, Laure; Psychari, Eleni; Minc, Nicolas; Simon, Damien; Bidard, François-Clément; Mathiot, Claire; Pierga, Jean-Yves; Fraisier, Vincent; Salamero, Jean; Saada, Véronique; Farace, Françoise; Vielh, Philippe; Malaquin, Laurent; Viovy, Jean-Louis

    2010-08-17

    We propose a unique method for cell sorting, "Ephesia," using columns of biofunctionalized superparamagnetic beads self-assembled in a microfluidic channel onto an array of magnetic traps prepared by microcontact printing. It combines the advantages of microfluidic cell sorting, notably the application of a well controlled, flow-activated interaction between cells and beads, and those of immunomagnetic sorting, notably the use of batch-prepared, well characterized antibody-bearing beads. On cell lines mixtures, we demonstrated a capture yield better than 94%, and the possibility to cultivate in situ the captured cells. A second series of experiments involved clinical samples--blood, pleural effusion, and fine needle aspirates--issued from healthy donors and patients with B-cell hematological malignant tumors (leukemia and lymphoma). The immunophenotype and morphology of B-lymphocytes were analyzed directly in the microfluidic chamber, and compared with conventional flow cytometry and visual cytology data, in a blind test. Immunophenotyping results using Ephesia were fully consistent with those obtained by flow cytometry. We obtained in situ high resolution confocal three-dimensional images of the cell nuclei, showing intranuclear details consistent with conventional cytological staining. Ephesia thus provides a powerful approach to cell capture and typing allowing fully automated high resolution and quantitative immunophenotyping and morphological analysis. It requires at least 10 times smaller sample volume and cell numbers than cytometry, potentially increasing the range of indications and the success rate of microbiopsy-based diagnosis, and reducing analysis time and cost. PMID:20679245

  19. MAGNET

    B. Curé

    During the winter shutdown, the magnet subsystems went through a full maintenance. The magnet was successfully warmed up to room temperature beginning of December 2008. The vacuum was broken later on by injecting nitrogen at a pressure just above one atmosphere inside the vacuum tank. This was necessary both to prevent any accidental humidity ingress, and to allow for a modification of the vacuum gauges on the vacuum tank and maintenance of the diffusion pumps. The vacuum gauges had to be changed, because of erratic variations on the measurements, causing spurious alarms. The new type of vacuum gauges has been used in similar conditions on the other LHC experiments and without problems. They are shielded against the stray field. The lubricants of the primary and diffusion pumps have been changed. Several minor modifications were also carried out on the equipment in the service cavern, with the aim to ease the maintenance and to allow possible intervention during operation. Spare sensors have been bought. Th...

  20. MAGNET

    Benoit Curé

    The magnet subsystems resumed operation early this spring. The vacuum pumping was restarted mid March, and the cryogenic power plant was restarted on March 30th. Three and a half weeks later, the magnet was at 4.5 K. The vacuum pumping system is performing well. One of the newly installed vacuum gauges had to be replaced at the end of the cool-down phase, as the values indicated were not coherent with the other pressure measurements. The correction had to be implemented quickly to be sure no helium leak could be at the origin of this anomaly. The pressure measurements have been stable and coherent since the change. The cryogenics worked well, and the cool-down went quite smoothly, without any particular difficulty. The automated start of the turbines had to be fine-tuned to get a smooth transition, as it was observed that the cooling power delivered by the turbines was slightly higher than needed, causing the cold box to stop automatically. This had no consequence as the cold box safety system acts to keep ...

  1. A magnetic vehicle realized tumor cell-targeted radiotherapy using low-dose radiation.

    Chen, Hsiao-Ping; Tung, Fu-I; Chen, Ming-Hong; Liu, Tse-Ying

    2016-03-28

    Radiotherapy, a common cancer treatment, often adversely affects the surrounding healthy tissue and/or cells. Some tumor tissue-focused radiation therapies have been developed to lower radiation-induced lesion formation; however, achieving tumor cell-targeted radiotherapy (i.e., precisely focusing the radiation efficacy to tumor cells) remains a challenge. In the present study, we developed a novel tumor cell-targeted radiotherapy, named targeted sensitization-enhanced radiotherapy (TSER), that exploits tumor-specific folic acid-conjugated carboxymethyl lauryl chitosan/superparamagnetic iron oxide (FA-CLC/SPIO) micelles to effectively deliver chlorin e6 (Ce6, a sonosensitizer) to mitochondria of HeLa cells under magnetic guidance. For the in vitro tests, the sensitization of Ce6 induced by ultrasound, that could weaken the radiation resistant ability of tumor cells, occurred only in Ce6-internalizing tumor cells. Therefore, low-dose X-ray irradiation, that was not harmful to normal cells, could exert high tumor cell-specific killing ability. The ratio of viable normal cells to tumor cells was increased considerably, from 7.8 (at 24h) to 97.1 (at 72h), after they had received TSER treatment. Our data suggest that TSER treatment significantly weakens tumor cells, resulting in decreased viability in vitro as well as decreased in vivo subcutaneous tumor growth in nude mice, while the adverse effects were minimal. Taken together, TSER treatment appears to be an effective, clinically feasible tumor cell-targeted radiotherapy that can solve the problems of traditional radiotherapy and photodynamic therapy. PMID:26892750

  2. The influence of surface functionalization on the enhanced internalization of magnetic nanoparticles in cancer cells

    The internalization and biocompatibility of iron oxide nanoparticles surface functionalized with four differently charged carbohydrates have been tested in the human cervical carcinoma cell line (HeLa). Neutral, positive, and negative iron oxide nanoparticles were obtained by coating with dextran, aminodextran, heparin, and dimercaptosuccinic acid, resulting in colloidal suspensions stable at pH 7 with similar aggregate size. No intracellular uptake was detected in cells incubated with neutral charged nanoparticles, while negative particles showed different behaviour depending on the nature of the coating. Thus, dimercaptosuccinic-coated nanoparticles showed low cellular uptake with non-toxic effects, while heparin-coated particles showed cellular uptake only at high nanoparticle concentrations and induced abnormal mitotic spindle configurations. Finally, cationic magnetic nanoparticles show excellent properties for possible in vivo biomedical applications such as cell tracking by magnetic resonance imaging (MRI) and cancer treatment by hyperthermia: (i) they enter into cells with high effectiveness, and are localized in endosomes; (ii) they can be easily detected inside cells by optical microscopy, (iii) they are retained for relatively long periods of time, and (iv) they do not induce any cytotoxicity.

  3. The influence of surface functionalization on the enhanced internalization of magnetic nanoparticles in cancer cells

    Villanueva, Angeles; Cañete, Magdalena; Roca, Alejandro G; Calero, Macarena; Veintemillas-Verdaguer, Sabino; Serna, Carlos J; del Puerto Morales, María; Miranda, Rodolfo

    2009-03-01

    The internalization and biocompatibility of iron oxide nanoparticles surface functionalized with four differently charged carbohydrates have been tested in the human cervical carcinoma cell line (HeLa). Neutral, positive, and negative iron oxide nanoparticles were obtained by coating with dextran, aminodextran, heparin, and dimercaptosuccinic acid, resulting in colloidal suspensions stable at pH 7 with similar aggregate size. No intracellular uptake was detected in cells incubated with neutral charged nanoparticles, while negative particles showed different behaviour depending on the nature of the coating. Thus, dimercaptosuccinic-coated nanoparticles showed low cellular uptake with non-toxic effects, while heparin-coated particles showed cellular uptake only at high nanoparticle concentrations and induced abnormal mitotic spindle configurations. Finally, cationic magnetic nanoparticles show excellent properties for possible in vivo biomedical applications such as cell tracking by magnetic resonance imaging (MRI) and cancer treatment by hyperthermia: (i) they enter into cells with high effectiveness, and are localized in endosomes; (ii) they can be easily detected inside cells by optical microscopy, (iii) they are retained for relatively long periods of time, and (iv) they do not induce any cytotoxicity.

  4. Magnetic Nanocomposite Scaffold-Induced Stimulation of Migration and Odontogenesis of Human Dental Pulp Cells through Integrin Signaling Pathways.

    Hyung-Mun Yun

    Full Text Available Magnetism is an intriguing physical cue that can alter the behaviors of a broad range of cells. Nanocomposite scaffolds that exhibit magnetic properties are thus considered useful 3D matrix for culture of cells and their fate control in repair and regeneration processes. Here we produced magnetic nanocomposite scaffolds made of magnetite nanoparticles (MNPs and polycaprolactone (PCL, and the effects of the scaffolds on the adhesion, growth, migration and odontogenic differentiation of human dental pulp cells (HDPCs were investigated. Furthermore, the associated signaling pathways were examined in order to elucidate the molecular mechanisms in the cellular events. The magnetic scaffolds incorporated with MNPs at varying concentrations (up to 10%wt supported cellular adhesion and multiplication over 2 weeks, showing good viability. The cellular constructs in the nanocomposite scaffolds played significant roles in the stimulation of adhesion, migration and odontogenesis of HDPCs. Cells were shown to adhere to substantially higher number when affected by the magnetic scaffolds. Cell migration tested by in vitro wound closure model was significantly enhanced by the magnetic scaffolds. Furthermore, odontogenic differentiation of HDPCs, as assessed by the alkaline phosphatase activity, mRNA expressions of odontogenic markers (DMP-1, DSPP,osteocalcin, and ostepontin, and alizarin red staining, was significantly stimulated by the magnetic scaffolds. Signal transduction was analyzed by RT-PCR, Western blotting, and confocal microscopy. The magnetic scaffolds upregulated the integrin subunits (α1, α2, β1 and β3 and activated downstream pathways, such as FAK, paxillin, p38, ERK MAPK, and NF-κB. The current study reports for the first time the significant impact of magnetic scaffolds in stimulating HDPC behaviors, including cell migration and odontogenesis, implying the potential usefulness of the magnetic scaffolds for dentin-pulp tissue engineering.

  5. Magnetic Nanocomposite Scaffold-Induced Stimulation of Migration and Odontogenesis of Human Dental Pulp Cells through Integrin Signaling Pathways

    Kim, Mi-joo; Kim, Jung-Ju; Lee, Jung-Hwan; Lee, Hae-Hyoung; Park, Kyung-Ran; Yi, Jin-Kyu; Kim, Hae-Won; Kim, Eun-cheol

    2015-01-01

    Magnetism is an intriguing physical cue that can alter the behaviors of a broad range of cells. Nanocomposite scaffolds that exhibit magnetic properties are thus considered useful 3D matrix for culture of cells and their fate control in repair and regeneration processes. Here we produced magnetic nanocomposite scaffolds made of magnetite nanoparticles (MNPs) and polycaprolactone (PCL), and the effects of the scaffolds on the adhesion, growth, migration and odontogenic differentiation of human dental pulp cells (HDPCs) were investigated. Furthermore, the associated signaling pathways were examined in order to elucidate the molecular mechanisms in the cellular events. The magnetic scaffolds incorporated with MNPs at varying concentrations (up to 10%wt) supported cellular adhesion and multiplication over 2 weeks, showing good viability. The cellular constructs in the nanocomposite scaffolds played significant roles in the stimulation of adhesion, migration and odontogenesis of HDPCs. Cells were shown to adhere to substantially higher number when affected by the magnetic scaffolds. Cell migration tested by in vitro wound closure model was significantly enhanced by the magnetic scaffolds. Furthermore, odontogenic differentiation of HDPCs, as assessed by the alkaline phosphatase activity, mRNA expressions of odontogenic markers (DMP-1, DSPP,osteocalcin, and ostepontin), and alizarin red staining, was significantly stimulated by the magnetic scaffolds. Signal transduction was analyzed by RT-PCR, Western blotting, and confocal microscopy. The magnetic scaffolds upregulated the integrin subunits (α1, α2, β1 and β3) and activated downstream pathways, such as FAK, paxillin, p38, ERK MAPK, and NF-κB. The current study reports for the first time the significant impact of magnetic scaffolds in stimulating HDPC behaviors, including cell migration and odontogenesis, implying the potential usefulness of the magnetic scaffolds for dentin-pulp tissue engineering. PMID:26382272

  6. Magnetic labeling and in vitro MR imaging of rat bone marrow mesenchymal stem cells

    Objective: To label rat bone marrow mesenchymal stem cells with feridex combined with poly-l-lysine (PLL), and to determine the feasibility of detection of magnetically labeled stem cells with MR imaging. Methods: Feridex were incubated with PLL for 1 hour to obtain a complex of feridex-PLL. Mesenchymal stem cells isolated from the bone marrows of Wistar rats were cultured and expanded. By the 4th passage, cells were co-incubated overnight with the feridex-PLL complex. Prussian blue staining for demonstrating intracytoplastic nanoparticles and trypan-blue exclusion test for cell viability were performed respectively at 24 h, 1 w, 2 w, 3 w after labeling. MR imaging of cell suspensions was performed by using T1WI, T2WI and T2* WI sequences at a clinical 1.5 T MR system. Results: Numerous intracytoplastic iron particles were stained with Prussian blue. With division of stern cells, the stained particles were seen decreased gradually. Trypan blue exclusion test at 24 h, 1 w, 2 w and 3 w showed that the viability of the labeled cells was 91.00%, 93.00%, 91.75%, and 92.50%, not significantly different with that of nonlabeled cells (P>0.05). For 103, 104 and l05 cells, T2 signal intensity decreased by 63.75%, 82.31% and 91.92% respectively, T2* signal intensity decreased by 68.24%, 83.01%, and 93.94% respectively. For 105 labeled cells, T2* signal intensity decreased by 93.75%, 75.92%, 41.75% and 8.83 % respectively at 24 h, 1 w, 2 w and 3 w after labeling. Conclusion: Magnetic labeling of rat bone marrow stem cells with feridex-PLL complex is feasible, efficient and safe. T2* WI is the most sensitive sequence to detect the labeled cells. The degree of T2 signal decreasing may be related to the cell count and division phase. (authors)

  7. Dragging Human Mesenchymal Stem Cells with the Aid of Supramolecular Assemblies of Single-Walled Carbon Nanotubes, Molecular Magnets, and Peptides in a Magnetic Field

    Ana Cláudia C. de Paula

    2015-01-01

    Full Text Available Human adipose-derived stem cells (hASCs are an attractive cell source for therapeutic applicability in diverse fields for the repair and regeneration of damaged or malfunctioning tissues and organs. There is a growing number of cell therapies using stem cells due to their characteristics of modulation of immune system and reduction of acute rejection. So a challenge in stem cells therapy is the delivery of cells to the organ of interest, a specific site. The aim of this paper was to investigate the effects of a supramolecular assembly composed of single-walled carbon nanotubes (SWCNT, molecular magnets (lawsone-Co-phenanthroline, and a synthetic peptide (FWYANHYWFHNAFWYANHYWFHNA in the hASCs cultures. The hASCs were isolated, characterized, expanded, and cultured with the SWCNT supramolecular assembly (SWCNT-MA. The assembly developed did not impair the cell characteristics, viability, or proliferation. During growth, the cells were strongly attached to the assembly and they could be dragged by an applied magnetic field of less than 0.3 T. These assemblies were narrower than their related allotropic forms, that is, multiwalled carbon nanotubes, and they could therefore be used to guide cells through thin blood capillaries within the human body. This strategy seems to be useful as noninvasive and nontoxic stem cells delivery/guidance and tracking during cell therapy.

  8. Observation of single neutral atoms in a large-magnetic-gradient vapour-cell magneto-optical trap

    Wang Jing; He Jun; Qiu Ying; Yang Bao-Dong; Zhao Jiang-Yan; Zhang Tian-Cai; Wang Jun-Min

    2008-01-01

    Single caesium atoms in a large-magnetic-gradient vapour-cell magneto-optical trap have been identified. The trapping of individual atoms is marked by the steps in fluorescence signal corresponding to the capture or loss of single atoms. The typical magnetic gradient is about 29 mT/cm, which evidently reduces the capture rate of magneto-optical trap.

  9. Investigation of superparamagnetic (Fe3O4) nanoparticles and magnetic field exposures on CHO-K1 cell line

    Coker, Zachary; Estlack, Larry; Hussain, Saber; Choi, Tae-Youl; Ibey, Bennett L.

    2016-03-01

    Rapid development in nanomaterial synthesis and functionalization has led to advanced studies in actuation and manipulation of cellular functions for biomedical applications. Often these actuation techniques employ externally applied magnetic fields to manipulate magnetic nanomaterials inside cell bodies in order to drive or trigger desired effects. While cellular interactions with low-frequency magnetic fields and nanoparticles have been extensively studied, the fundamental mechanisms behind these interactions remain poorly understood. Additionally, modern investigations on these concurrent exposure conditions have been limited in scope, and difficult to reproduce. This study presents an easily reproducible method of investigating the biological impact of concurrent magnetic field and nanoparticle exposure conditions using an in-vitro CHO-K1 cell line model, with the purpose of establishing grounds for in-depth fundamental studies of the mechanisms driving cellular-level interactions. Cells were cultured under various nanoparticle and magnetic field exposure conditions from 0 to 500 μg/ml nanoparticle concentrations, and DC, 50 Hz, or 100 Hz magnetic fields with 2.0 mT flux density. Cells were then observed by confocal fluorescence microscopy, and subject to biological assays to determine the effects of concurrent extreme-low frequency magnetic field and nanoparticle exposures on cellnanoparticle interactions, such as particle uptake and cell viability by MTT assay. Current results indicate little to no variation in effect on cell cultures based on magnetic field parameters alone; however, it is clear that deleterious synergistic effects of concurrent exposure conditions exist based on a significant decrease in cell viability when exposed to high concentrations of nanoparticles and concurrent magnetic field.

  10. Highly efficient mesenchymal stem cell proliferation on poly-ε-caprolactone nanofibers with embedded magnetic nanoparticles

    Daňková J

    2015-12-01

    Full Text Available Jana Danková,1,2 Matej Buzgo,1,3,4 Jana Vejpravová,5 Simona Kubíčková,5 Věra Sovková,1,2 Lucie Vysloužilová,4,6 Alice Mantlíková,5 Alois Nečas,7 Evžen Amler1–31Laboratory of Tissue Engineering, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic; 2Institute of Biophysics, Second Faculty of Medicine, Charles University in Prague, Prague, Czech Republic; 3Faculty of Biomedical Engineering, Czech Technical University in Prague, Kladno, Czech Republic; 4University Center for Energy Efficient Buildings, Czech Technical University in Prague, Bustehrad, Czech Republic; 5Department of Magnetic Nanosystems, Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic; 6Department of Nonwoven Textiles, Faculty of Textile Engineering, Technical University of Liberec, Liberec, Czech Republic; 7Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech RepublicAbstract: In this study, we have developed a combined approach to accelerate the proliferation of mesenchymal stem cells (MSCs in vitro, using a new nanofibrous scaffold made by needleless electrospinning from a mixture of poly-ε-caprolactone and magnetic particles. The biological characteristics of porcine MSCs were investigated while cultured in vitro on composite scaffold enriched with magnetic nanoparticles. Our data indicate that due to the synergic effect of the poly-ε-caprolactone nanofibers and magnetic particles, cellular adhesion and proliferation of MSCs is enhanced and osteogenic differentiation is supported. The cellular and physical attributes make this new scaffold very promising for the acceleration of efficient MSC proliferation and regeneration of hard tissues.Keywords: magnetic particles, mesenchymal stem cells, nanofibers, tissue engineering 

  11. Magnetic fluid hyperthermia enhances cytotoxicity of bortezomib in sensitive and resistant cancer cell lines

    Alvarez-Berríos MP

    2013-12-01

    Full Text Available Merlis P Alvarez-Berríos,1 Amalchi Castillo,1 Carlos Rinaldi,1–3 Madeline Torres-Lugo1 1Department of Chemical Engineering, University of Puerto Rico, Mayagüez, Puerto Rico; 2J Crayton Pruitt Family Department of Biomedical Engineering, 3Department of Chemical Engineering, University of Florida, Gainesville, FL, USA Abstract: The proteasome inhibitor bortezomib (BZ has shown promising results in some types of cancer, but in others it has had minimal activity. Recent studies have reported enhanced efficacy of BZ when combined with hyperthermia. However, the use of magnetic nanoparticles to induce hyperthermia in combination with BZ has not been reported. This novel hyperthermia modality has shown better potentiation of chemotherapeutics over other types of hyperthermia. We hypothesized that inducing hyperthermia via magnetic nanoparticles (MFH would enhance the cytotoxicity of BZ in BZ-sensitive and BZ-resistant cancer cells more effectively than hyperthermia using a hot water bath (HWH. Studies were conducted using BZ in combination with MFH in two BZ-sensitive cell lines (MDA-MB-468, Caco-2, and one BZ-resistant cell line (A2780 at two different conditions, ie, 43°C for 30 minutes and 45°C for 30 minutes. These experiments were compared with combined application of HWH and BZ. The results indicate enhanced potentiation between hyperthermic treatment and BZ. MFH combined with BZ induced cytotoxicity in sensitive and resistant cell lines to a greater extent than HWH under the same treatment conditions. The observation that MFH sensitizes BZ-resistant cell lines makes this approach a potentially effective anticancer therapy platform. Keywords: magnetic fluid hyperthermia, hot water hyperthermia, BZ, enhanced cytotoxicity, thermal sensitization

  12. In vivo tracking of human neural stem cells with 19F magnetic resonance imaging.

    Philipp Boehm-Sturm

    Full Text Available BACKGROUND: Magnetic resonance imaging (MRI is a promising tool for monitoring stem cell-based therapy. Conventionally, cells loaded with ironoxide nanoparticles appear hypointense on MR images. However, the contrast generated by ironoxide labeled cells is neither specific due to ambiguous background nor quantitative. A strategy to overcome these drawbacks is (19F MRI of cells labeled with perfluorocarbons. We show here for the first time that human neural stem cells (NSCs, a promising candidate for clinical translation of stem cell-based therapy of the brain, can be labeled with (19F as well as detected and quantified in vitro and after brain implantation. METHODOLOGY/PRINCIPAL FINDINGS: Human NSCs were labeled with perfluoropolyether (PFPE. Labeling efficacy was assessed with (19F MR spectroscopy, influence of the label on cell phenotypes studied by immunocytochemistry. For in vitro MRI, NSCs were suspended in gelatin at varying densities. For in vivo experiments, labeled NSCs were implanted into the striatum of mice. A decrease of cell viability was observed directly after incubation with PFPE, which re-normalized after 7 days in culture of the replated cells. No label-related changes in the numbers of Ki67, nestin, GFAP, or βIII-tubulin+ cells were detected, both in vitro and on histological sections. We found that 1,000 NSCs were needed to accumulate in one image voxel to generate significant signal-to-noise ratio in vitro. A detection limit of ∼10,000 cells was found in vivo. The location and density of human cells (hunu+ on histological sections correlated well with observations in the (19F MR images. CONCLUSION/SIGNIFICANCE: Our results show that NSCs can be efficiently labeled with (19F with little effects on viability or proliferation and differentiation capacity. We show for the first time that (19F MRI can be utilized for tracking human NSCs in brain implantation studies, which ultimately aim for restoring loss of function after

  13. Electric Equivalent Models of Intrinsic Recombination Velocities of a Bifacial Silicon Solar Cell under Frequency Modulation and Magnetic Field Effect

    Nd. Thiam; A. Diao; NDiaye, M; Dieng, A.; Thiam, A.; Sarr, M.; A.S. Maiga; G. Sissoko

    2012-01-01

    In this study, we present a theoretical study of the photogenerated charge carriers in the base of an illuminated n+-p-p+ crystalline silicon solar cell under an external magnetic field. By solving the charge carriers’ continuity equation, the dependence of diffusion coefficient and the photocurrent density on the frequency modulation and magnetic field, is studied. Hence, the study of intrinsic recombination velocities at the junction Sfo1 and rear side Sbo1 of the solar cell, leads to elect...

  14. Static magnetic fields modulate X-ray-induced DNA damage in human glioblastoma primary cells

    Although static magnetic fields (SMFs) are used extensively in the occupational and medical fields, few comprehensive studies have investigated their possible genotoxic effect and the findings are controversial. With the advent of magnetic resonance imaging-guided radiation therapy, the potential effects of SMFs on ionizing radiation (IR) have become increasingly important. In this study we focused on the genotoxic effect of 80 mT SMFs, both alone and in combination with (i.e. preceding or following) X-ray (XR) irradiation, on primary glioblastoma cells in culture. The cells were exposed to: (1) SMFs alone; (2) XRs alone; (3) XR, with SMFs applied during recovery; (4) SMFs both before and after XR irradiation. XR-induced DNA damage was analyzed by Single Cell Gel Electrophoresis assay (comet assay) using statistical tools designed to assess the tail DNA (TD) and tail length (TL) as indicators of DNA fragmentation. Mitochondrial membrane potential, known to be affected by IR, was assessed using the JC-1 mitochondrial probe. Our results showed that exposure of cells to 5 Gy of XR irradiation alone led to extensive DNA damage, which was significantly reduced by post-irradiation exposure to SMFs. The XR-induced loss of mitochondrial membrane potential was to a large extent averted by exposure to SMFs. These data suggest that SMFs modulate DNA damage and/or damage repair, possibly through a mechanism that affects mitochondria. (author)

  15. The influence of particle size and static magnetic fields on the uptake of magnetic nanoparticles into three dimensional cell-seeded collagen gel cultures.

    Lewis, Emily E L; Child, Hannah W; Hursthouse, Andrew; Stirling, David; McCully, Mark; Paterson, David; Mullin, Margaret; Berry, Catherine C

    2015-08-01

    Over recent decades there has been and continues to be major advances in the imaging, diagnosis and potential treatment of medical conditions, by the use of magnetic nanoparticles. However, to date the majority of cell delivery studies employ a traditional 2D monolayer culture. This article aims to determine the ability of various sized magnetic nanoparticles to penetrate and travel through a cell seeded collagen gel model, in the presence or absence of a magnetic field. Three different sized (100, 200, and 500 nm) nanoparticles were employed in the study. The results showed cell viability was unaffected by the presence of nanoparticles over a 24-h test period. The initial uptake of the 100 nm nanoparticle into the collagen gel structure was superior compared to the larger sized nanoparticles under the influence of a magnetic field and incubated for 24 h. Interestingly, it was the 200 nm nanoparticles, which proved to penetrate the gel furthest, under the influence of a magnetic field, during the initial culture stage after 1-h incubation. PMID:25358626

  16. Effects of surfactants on agarose-based magnetic polymer electrolyte for dye-sensitized solar cells

    Highlights: ► A novel agarose magnetic polymer electrolyte for DSSC was investigated. ► Four surfactants were introduced to improve the dispersivity of Fe3O4 nanoparticle. ► Fe3O4 nanoparticles are well dispersed and the ionic conductivity was improved. ► TW-80 was selected as the proper surfactant for magnetic polymer electrolyte. -- Abstract: Four surfactants, sodium dodecyl sulfate (SDS), polyvinylpyrrolidone (PVP), polyethylene glycol (PEG200) and polysorbate 80 (TW-80), were added to disperse Fe3O4 nanoparticles in agarose based magnetic polymer electrolyte, for the purpose of improving the performance of dye-sensitized solar cell (DSSC). Fourier transform infrared spectroscopy (FTIR) was employed to characterize the interactions between surfactants and magnetic polymer electrolyte. TW-80 and PEG200 showed good dispersion properties according to surface morphology tests. Through electrochemical impedance spectroscopy (EIS) study, the ionic conductivity, charge transfer resistance, charge recombination resistance and electron lifetime of polymer electrolytes were all improved by modification, while TW-80 modified electrolyte reached the highest ionic conductivity of 2.98 × 10−3 S/cm. Moreover, the photoelectric properties were also significantly enhanced and the best energy conversion efficiency achieved 1.83% with TW-80 modification

  17. High resolution in-operando microimaging of solar cells with pulsed electrically-detected magnetic resonance

    Katz, Itai; Fehr, Matthias; Schnegg, Alexander; Lips, Klaus; Blank, Aharon

    2015-02-01

    The in-operando detection and high resolution spatial imaging of paramagnetic defects, impurities, and states becomes increasingly important for understanding loss mechanisms in solid-state electronic devices. Electron spin resonance (ESR), commonly employed for observing these species, cannot meet this challenge since it suffers from limited sensitivity and spatial resolution. An alternative and much more sensitive method, called electrically-detected magnetic resonance (EDMR), detects the species through their magnetic fingerprint, which can be traced in the device's electrical current. However, until now it could not obtain high resolution images in operating electronic devices. In this work, the first spatially-resolved electrically-detected magnetic resonance images (EDMRI) of paramagnetic states in an operating real-world electronic device are provided. The presented method is based on a novel microwave pulse sequence allowing for the coherent electrical detection of spin echoes in combination with powerful pulsed magnetic-field gradients. The applicability of the method is demonstrated on a device-grade 1-μm-thick amorphous silicon (a-Si:H) solar cell and an identical device that was degraded locally by an electron beam. The degraded areas with increased concentrations of paramagnetic defects lead to a local increase in recombination that is mapped by EDMRI with ∼20-μm-scale pixel resolution. The novel approach presented here can be widely used in the nondestructive in-operando three-dimensional characterization of solid-state electronic devices with a resolution potential of less than 100 nm.

  18. High resolution in-operando microimaging of solar cells with pulsed electrically-detected magnetic resonance.

    Katz, Itai; Fehr, Matthias; Schnegg, Alexander; Lips, Klaus; Blank, Aharon

    2015-02-01

    The in-operando detection and high resolution spatial imaging of paramagnetic defects, impurities, and states becomes increasingly important for understanding loss mechanisms in solid-state electronic devices. Electron spin resonance (ESR), commonly employed for observing these species, cannot meet this challenge since it suffers from limited sensitivity and spatial resolution. An alternative and much more sensitive method, called electrically-detected magnetic resonance (EDMR), detects the species through their magnetic fingerprint, which can be traced in the device's electrical current. However, until now it could not obtain high resolution images in operating electronic devices. In this work, the first spatially-resolved electrically-detected magnetic resonance images (EDMRI) of paramagnetic states in an operating real-world electronic device are provided. The presented method is based on a novel microwave pulse sequence allowing for the coherent electrical detection of spin echoes in combination with powerful pulsed magnetic-field gradients. The applicability of the method is demonstrated on a device-grade 1-μm-thick amorphous silicon (a-Si:H) solar cell and an identical device that was degraded locally by an electron beam. The degraded areas with increased concentrations of paramagnetic defects lead to a local increase in recombination that is mapped by EDMRI with ∼20-μm-scale pixel resolution. The novel approach presented here can be widely used in the nondestructive in-operando three-dimensional characterization of solid-state electronic devices with a resolution potential of less than 100 nm. PMID:25557860

  19. Red blood cell membrane camouflaged magnetic nanoclusters for imaging-guided photothermal therapy.

    Ren, Xiaoqing; Zheng, Rui; Fang, Xiaoling; Wang, Xiaofei; Zhang, Xiaoyan; Yang, Wuli; Sha, Xianyi

    2016-06-01

    Along with intrinsic magnetic resonance imaging (MRI) advantages, iron oxide nanomaterials capable of photothermal conversion have been reported very recently and have again raised great interest in their designs among biomedical researchers. However, like other inorganic nanomaterials, high macrophage uptake, short blood retention time and unfavorable biodistributions have strongly hampered their applications in vivo. To solve these problems, a rational design of red blood cell (RBC) membrane camouflaged iron oxide magnetic clusters (MNC@RBCs) is presented in this paper. Our data show that by simply introducing an "ultra-stealth" biomimetic coating to iron oxide magnetic nanoclusters (MNCs), MNC@RBCs maintain the imaging and photothermal functionalities inherited from MNCs cores while achieving much lower nonspecific macrophage uptake and dramatically altered fate in vivo. MNC@RBCs with superior prolonged blood retention time, preferred high tumor accumulation and relatively lowered liver biodistribution are demonstrated when injected intravenously in mice, leading to greatly enhanced photothermal therapeutic efficacy by a single treatment without further magnetic force manipulation. Our study illustrates a well prepared integration of MNCs and RBCs, exploiting advantages of both functionalities within a single unit and suggests a promising future for iron-based nanomaterials application in vivo. PMID:27031929

  20. Stray magnetic field influence on the CPT resonance in a coated Rb vacuum cell

    Taskova, E.; Alipieva, E.; Todorov, G.

    2016-03-01

    Interaction of a resonant laser beam with an atomic absorption medium creates population redistribution and interference between atomic levels. This anisotropy of the medium is experimentally observed as coherent population trapping (CPT) or electromagnetically induced transparency (EIT). Due to the small sub-natural width of the CPT and EIT resonances, they find wide applications in metrology, quantum optics, atom cooling. A non-compensated stray magnetic field (SMF) can change the shape and sign of the resonance or destroy it completely. In this work, we present an experimental and theoretical investigation of the influence of a stray magnetic field on the CPT resonances obtained on Zeeman sublevels of the D1 line of 87Rb in a paraffin-coated vacuum cell. The role is clarified of the polarization moments with different rank in creating the integral registered fluorescent signal in the presence of a stray magnetic field. It is shown that a transverse magnetic field plays an important role in changing the shape of the signal.

  1. Effects of exposure to gradient magnetic fields emitted by nuclear magnetic resonance devices on clonogenic potential and proliferation of human hematopoietic stem cells.

    Iachininoto, Maria Grazia; Camisa, Vincenzo; Leone, Lucia; Pinto, Rosanna; Lopresto, Vanni; Merla, Caterina; Giorda, Ezio; Carsetti, Rita; Zaffina, Salvatore; Podda, Maria Vittoria; Teofili, Luciana; Grassi, Claudio

    2016-05-01

    This study investigates effects of gradient magnetic fields (GMFs) emitted by magnetic resonance imaging (MRI) devices on hematopoietic stem cells. Field measurements were performed to assess exposure to GMFs of staff working at 1.5 T and 3 T MRI units. Then an exposure system reproducing measured signals was realized to expose in vitro CD34+ cells to GMFs (1.5 T-protocol and 3 T-protocol). CD34+ cells were obtained by Fluorescence Activated Cell Sorting from six blood donors and three MRI-exposed workers. Blood donor CD34+ cells were exposed in vitro for 72 h to 1.5 T or 3 T-protocol and to sham procedure. Cells were then cultured and evaluated in colony forming unit (CFU)-assay up to 4 weeks after exposure. Results showed that in vitro GMF exposure did not affect cell proliferation but instead induced expansion of erythroid and monocytes progenitors soon after exposure and for the subsequent 3 weeks. No decrease of other clonogenic cell output (i.e., CFU-granulocyte/erythroid/macrophage/megakaryocyte and CFU-granulocyte/macrophage) was noticed, nor exposed CD34+ cells underwent the premature exhaustion of their clonogenic potential compared to sham-exposed controls. On the other hand, pilot experiments showed that CD34+ cells exposed in vivo to GMFs (i.e., samples from MRI workers) behaved in culture similarly to sham-exposed CD34+ cells, suggesting that other cells and/or microenvironment factors might prevent GMF effects on hematopoietic stem cells in vivo. Accordingly, GMFs did not affect the clonogenic potential of umbilical cord blood CD34+ cells exposed in vitro together with the whole mononuclear cell fraction. Bioelectromagnetics. 37:201-211, 2016. © 2016 Wiley Periodicals, Inc. PMID:26992028

  2. MAGNET

    Benoit Curé

    The cooling down to the nominal temperature of 4.5 K was achieved at the beginning of August, in conjunction with the completion of the installation work of the connection between the power lines and the coil current leads. The temperature gradient on the first exchanger of the cold box is now kept within the nominal range. A leak of lubricant on a gasket of the helium compressor station installed at the surface was observed and several corrective actions were necessary to bring the situation back to normal. The compressor had to be refilled with lubricant and a regeneration of the filters and adsorbers was necessary. The coil cool down was resumed successfully, and the cryogenics is running since then with all parameters being nominal. Preliminary tests of the 20kA coil power supply were done earlier at full current through the discharge lines into the dump resistors, and with the powering busbars from USC5 to UXC5 without the magnet connected. On Monday evening August 25th, at 8pm, the final commissionin...

  3. MAGNET

    B. Curé

    The first phase of the commissioning ended in August by a triggered fast dump at 3T. All parameters were nominal, and the temperature recovery down to 4.5K was carried out in two days by the cryogenics. In September, series of ramps were achieved up to 3 and finally 3.8T, while checking thoroughly the detectors in the forward region, measuring any movement of and around the HF. After the incident of the LHC accelerator on September 19th, corrective actions could be undertaken in the forward region. When all these displacements were fully characterized and repetitive, with no sign of increments in displacement at each field ramp, it was possible to start the CRAFT, Cosmic Run at Four Tesla (which was in fact at 3.8T). The magnet was ramped up to 18.16kA and the 3 week run went smoothly, with only 4 interruptions: due to the VIP visits on 21st October during the LHC inauguration day; a water leak on the cooling demineralized water circuit, about 1 l/min, that triggered a stop of the cooling pumps, and resulte...

  4. MAGNET

    Benoit Curé

    2013-01-01

    Maintenance work and consolidation activities on the magnet cryogenics and its power distribution are progressing according to the schedules. The manufacturing of the two new helium compressor frame units has started. The frame units support the valves, all the sensors and the compressors with their motors. This activity is subcontracted. The final installation and the commissioning at CERN are scheduled for March–April 2014. The overhauls of existing cryogenics equipment (compressors, motors) are in progress. The reassembly of the components shall start in early 2014. The helium drier, to be installed on the high-pressure helium piping, has been ordered and will be delivered in the first trimester of 2014. The power distribution for the helium compressors in SH5 on the 3.3kV network is progressing. The 3.3kV switches, between each compressor and its hot spare compressor, are being installed, together with the power cables for the new compressors. The 3.3kV electrical switchboards in SE5 will ...

  5. Human induced pluripotent stem cells labeled with fluorescent magnetic nanoparticles for targeted imaging and hyperthermia therapy for gastric cancer

    Human induced pluripotent stem (iPS) cells exhibit great potential for generating functional human cells for medical therapies. In this paper, we report for use of human iPS cells labeled with fluorescent magnetic nanoparticles (FMNPs) for targeted imaging and synergistic therapy of gastric cancer cells in vivo. Human iPS cells were prepared and cultured for 72 h. The culture medium was collected, and then was co-incubated with MGC803 cells. Cell viability was analyzed by the MTT method. FMNP-labeled human iPS cells were prepared and injected into gastric cancer-bearing nude mice. The mouse model was observed using a small-animal imaging system. The nude mice were irradiated under an external alternating magnetic field and evaluated using an infrared thermal mapping instrument. Tumor sizes were measured weekly. iPS cells and the collected culture medium inhibited the growth of MGC803 cells. FMNP-labeled human iPS cells targeted and imaged gastric cancer cells in vivo, as well as inhibited cancer growth in vivo through the external magnetic field. FMNP-labeled human iPS cells exhibit considerable potential in applications such as targeted dual-mode imaging and synergistic therapy for early gastric cancer

  6. Immunological identification of human T cells intracranially and tracing of neuronal projections by magnetic resonance imaging

    This report describes the preparation and utilization of paramagnetically labelled proteins to trace neural projections in vivo, and to distinguish between human T cells and bovine T cells implanted into canine brain. The proteins are covalently coupled to the chelator (DTPA), then labelled with gadolinium and visualized in vivo by magnetic resonance imaging (MRI) techniques. Gadolinium labelled horseradish peroxidase (HRP) was injected into the auditory cortex of adult cats (1-7 μ1 containing 50 μg HRP per μ1) and 48-72 hours later the brain was imaged by MRI. The HRP was labelled with an average of 20 DTPA per HRP. MRI unambiguously identified the HRP injection sites and the sites of neural projections in the medical geniculate body (MGB). MGB localization of HRP-Gd was confirmed histologically demonstrating that MRI can distinguish between paramagnetically labelled protein and local environment effects in the brain (i.e. gray vs white matter). Two monoclonal antibodies against human T cells were labelled with gadolinium. The distinguished by MRI, human from bovine T cells implanted into canine brains (each implant contained 10 million cells in 40 μ1). The T1 weighted and calculated images readily identified the human T cells as a lesion of <4 mm while the bovine T cells did not yield a significant MRI signal. The ratio of DTPA to protein during the coupling procedure, affects the formation of protein aggregates by crosslinking

  7. Magnetic particle spectroscopy allows precise quantification of nanoparticles after passage through human brain microvascular endothelial cells

    Gräfe, C.; Slabu, I.; Wiekhorst, F.; Bergemann, C.; von Eggeling, F.; Hochhaus, A.; Trahms, L.; Clement, J. H.

    2016-06-01

    Crossing the blood–brain barrier is an urgent requirement for the treatment of brain disorders. Superparamagnetic iron oxide nanoparticles (SPIONs) are a promising tool as carriers for therapeutics because of their physical properties, biocompatibility, and their biodegradability. In order to investigate the interaction of nanoparticles with endothelial cell layers in detail, in vitro systems are of great importance. Human brain microvascular endothelial cells are a well-suited blood–brain barrier model. Apart from generating optimal conditions for the barrier-forming cell units, the accurate detection and quantification of SPIONs is a major challenge. For that purpose we use magnetic particle spectroscopy to sensitively and directly quantify the SPION-specific iron content. We could show that SPION concentration depends on incubation time, nanoparticle concentration and location. This model system allows for further investigations on particle uptake and transport at cellular barriers with regard to parameters including particles’ shape, material, size, and coating.

  8. Magnetic particle spectroscopy allows precise quantification of nanoparticles after passage through human brain microvascular endothelial cells.

    Gräfe, C; Slabu, I; Wiekhorst, F; Bergemann, C; von Eggeling, F; Hochhaus, A; Trahms, L; Clement, J H

    2016-06-01

    Crossing the blood-brain barrier is an urgent requirement for the treatment of brain disorders. Superparamagnetic iron oxide nanoparticles (SPIONs) are a promising tool as carriers for therapeutics because of their physical properties, biocompatibility, and their biodegradability. In order to investigate the interaction of nanoparticles with endothelial cell layers in detail, in vitro systems are of great importance. Human brain microvascular endothelial cells are a well-suited blood-brain barrier model. Apart from generating optimal conditions for the barrier-forming cell units, the accurate detection and quantification of SPIONs is a major challenge. For that purpose we use magnetic particle spectroscopy to sensitively and directly quantify the SPION-specific iron content. We could show that SPION concentration depends on incubation time, nanoparticle concentration and location. This model system allows for further investigations on particle uptake and transport at cellular barriers with regard to parameters including particles' shape, material, size, and coating. PMID:27163489

  9. Signs of hypervascularization at magnetic resonance imaging in bone metastases from renal cell carcinoma

    Objective: To evaluate the frequency of hypervascularization by visualizing vascular structures inside or around bone metastases from renal cell carcinoma. Materials and methods: Magnetic resonance imaging studies of 13 untreated patients with diagnosis of renal cell carcinoma and 15 metastatic bone lesions were retrospectively evaluated. Results: Signs of hypervascularization were found in 12 of the 15 bone lesions (80%), 6 of them localized in the lumbar spine, 3 in the hip, 3 in the thoracic spine, 1 in the ulna and 1 in the tibia. Conclusion: The high frequency of hypervascularization of bone metastases from renal cell carcinoma found in the present study may suggest that the renal etiology is a useful parameter in the evaluation of a usual clinical presentation of a single bone lesion with unknown primary neoplasm. (author)

  10. A hybrid magnetic/complementary metal oxide semiconductor three-context memory bit cell for non-volatile circuit design

    After decades of continued scaling to the beat of Moore's law, it now appears that conventional silicon based devices are approaching their physical limits. In today's deep-submicron nodes, a number of short-channel and quantum effects are emerging that affect the manufacturing process, as well as, the functionality of the microelectronic systems-on-chip. Spintronics devices that exploit both the intrinsic spin of the electron and its associated magnetic moment, in addition to its fundamental electronic charge, are promising solutions to circumvent these scaling threats. Being compatible with the CMOS technology, such devices offer a promising synergy of radiation immunity, infinite endurance, non-volatility, increased density, etc. In this paper, we present a hybrid (magnetic/CMOS) cell that is able to store and process data both electrically and magnetically. The cell is based on perpendicular spin-transfer torque magnetic tunnel junctions (STT-MTJs) and is suitable for use in magnetic random access memories and reprogrammable computing (non-volatile registers, processor cache memories, magnetic field-programmable gate arrays, etc). To demonstrate the potential our hybrid cell, we physically implemented a small hybrid memory block using 45 nm × 45 nm round MTJs for the magnetic part and 28 nm fully depleted silicon on insulator (FD-SOI) technology for the CMOS part. We also report the cells measured performances in terms of area, robustness, read/write speed and energy consumption

  11. Use of a SQUID array to detect T-cells with magnetic nanoparticles in determining transplant rejection

    Flynn, Edward R. [Senior Scientific, 11109 Country Club NE, Albuquerque, NM 87111 (United States)]. E-mail: seniorsci@nmia.com; Bryant, H.C. [Senior Scientific, 11109 Country Club NE, Albuquerque, NM 87111 (United States); Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131 (United States); Bergemann, Christian [Chemicell GmbH, Berlin (Germany); Larson, Richard S. [Cancer Research and Treatment Center, University of New Mexico, Albuquerque, NM 87131 (United States); Lovato, Debbie [Cancer Research and Treatment Center, University of New Mexico, Albuquerque, NM 87131 (United States); Sergatskov, Dmitri A. [Senior Scientific, 11109 Country Club NE, Albuquerque, NM 87111 (United States)

    2007-04-15

    Acute rejection in organ transplant is signaled by the proliferation of T-cells that target and kill the donor cells requiring painful biopsies to detect rejection onset. An alternative non-invasive technique is proposed using a multi-channel superconducting quantum interference device (SQUID) magnetometer to detect T-cell lymphocytes in the transplanted organ labeled with magnetic nanoparticles conjugated to antibodies specifically attached to lymphocytic ligand receptors. After a magnetic field pulse, the T-cells produce a decaying magnetic signal with a characteristic time of the order of a second. The extreme sensitivity of this technique, 10{sup 5} cells, can provide early warning of impending transplant rejection and monitor immune-suppressive chemotherapy.

  12. Use of a SQUID array to detect T-cells with magnetic nanoparticles in determining transplant rejection

    Flynn, Edward R.; Bryant, H. C.; Bergemann, Christian; Larson, Richard S.; Lovato, Debbie; Sergatskov, Dmitri A.

    2007-04-01

    Acute rejection in organ transplant is signaled by the proliferation of T-cells that target and kill the donor cells requiring painful biopsies to detect rejection onset. An alternative non-invasive technique is proposed using a multi-channel superconducting quantum interference device (SQUID) magnetometer to detect T-cell lymphocytes in the transplanted organ labeled with magnetic nanoparticles conjugated to antibodies specifically attached to lymphocytic ligand receptors. After a magnetic field pulse, the T-cells produce a decaying magnetic signal with a characteristic time of the order of a second. The extreme sensitivity of this technique, 10 5 cells, can provide early warning of impending transplant rejection and monitor immune-suppressive chemotherapy.

  13. Use of a SQUID array to detect T-cells with magnetic nanoparticles in determining transplant rejection

    Acute rejection in organ transplant is signaled by the proliferation of T-cells that target and kill the donor cells requiring painful biopsies to detect rejection onset. An alternative non-invasive technique is proposed using a multi-channel superconducting quantum interference device (SQUID) magnetometer to detect T-cell lymphocytes in the transplanted organ labeled with magnetic nanoparticles conjugated to antibodies specifically attached to lymphocytic ligand receptors. After a magnetic field pulse, the T-cells produce a decaying magnetic signal with a characteristic time of the order of a second. The extreme sensitivity of this technique, 105 cells, can provide early warning of impending transplant rejection and monitor immune-suppressive chemotherapy

  14. Comparison of magnetic resonance angiography and conventional angiography in sickle cell disease: clinical significance and realibility

    We retrospectively reviewed the medical records and conventional angiograms of 21 patients with known sickle cell disease, who underwent a total of 50 magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) studies. MRA and conventional angiography were assessed separately for evidence of stenosis or occulusion. Follow up MRI/MRA studies were also assessed for evidence of progression, regression or stability of the disease in these patients. In the carotid circulation, MRA made the correct diagnosis in 85% of the vessels evaluated with a sensitivity of 80.5% and a specificity of 94%. MRA was also found to show evidence of disease progression, more often than did MRI or the clinical condition of the patients. (orig.)

  15. In-gas-cell laser spectroscopy for magnetic dipole moment of $^{199}$Pt toward $N=$ 126

    Hirayama, Y; Watanabe, Y X; Jeong, S C; Jung, H S; Kakiguchi, Y; Kimura, S; Moon, J Y; Oyaizu, M; Park, J H; Schury, P; Wada, M; Miyatake, H

    2016-01-01

    Magnetic dipole moment and mean-square charge radius of $^{199}$Pt ($I^{\\pi}=$ 5/2$^-$) have been evaluated for the first time from the investigation of the hyperfine splitting of the $\\lambda_1=$ 248.792 nm transition by in-gas-cell laser ionization spectroscopy. Neutron-rich nucleus $^{199}$Pt was produced by multi-nucleon transfer reaction at the KISS where the nuclear spectroscopy in the vicinity of $N=$ 126 is planed from the aspect of an astrophysical interest as well as the nuclear structure. Measured magnetic dipole moment $+$0.63(13)$\\mu_{\\rm N}$ is consistent with the systematics of those of nuclei with $I^{\\pi}=$ 5/2$^-$. The deformation parameter $|^{1/2}|$ evaluated from the isotope shift indicates the gradual shape change to spherical shape of platinum isotopes with increasing neutron number toward $N=$ 126.

  16. Comparison of magnetic resonance angiography and conventional angiography in sickle cell disease: clinical significance and realibility

    Kandeel, A.Y. [Dept. of Radiology, Mansoura Univ. Hospital (Egypt); Zimmerman, R.A. [Dept. of Radiology, The Children`s Hospital of Philadelphia, PA (United States); Ohene-Frempong, K. [Div. of Hematology, The Children`s Hospital of Philadelphia, PA (United States)

    1996-07-01

    We retrospectively reviewed the medical records and conventional angiograms of 21 patients with known sickle cell disease, who underwent a total of 50 magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) studies. MRA and conventional angiography were assessed separately for evidence of stenosis or occulusion. Follow up MRI/MRA studies were also assessed for evidence of progression, regression or stability of the disease in these patients. In the carotid circulation, MRA made the correct diagnosis in 85% of the vessels evaluated with a sensitivity of 80.5% and a specificity of 94%. MRA was also found to show evidence of disease progression, more often than did MRI or the clinical condition of the patients. (orig.)

  17. Effect of Magnetic Nanoparticles on Tobacco BY-2 Cell Suspension Culture

    Rene Kizek

    2012-12-01

    Full Text Available Nanomaterials are structures whose exceptionality is based on their large surface, which is closely connected with reactivity and modification possibilities. Due to these properties nanomaterials are used in textile industry (antibacterial textiles with silver nanoparticles, electronics (high-resolution imaging, logical circuits on the molecular level and medicine. Medicine represents one of the most important fields of application of nanomaterials. They are investigated in connection with targeted therapy (infectious diseases, malignant diseases or imaging (contrast agents. Nanomaterials including nanoparticles have a great application potential in the targeted transport of pharmaceuticals. However, there are some negative properties of nanoparticles, which must be carefully solved, as hydrophobic properties leading to instability in aqueous environment, and especially their possible toxicity. Data about toxicity of nanomaterials are still scarce. Due to this fact, in this work we focused on studying of the effect of magnetic nanoparticles (NPs and modified magnetic nanoparticles (MNPs on tobacco BY-2 plant cell suspension culture. We aimed at examining the effect of NPs and MNPs on growth, proteosynthesis — total protein content, thiols — reduced (GSH and oxidized (GSSG glutathione, phytochelatins PC2-5, glutathione S-transferase (GST activity and antioxidant activity of BY-2 cells. Whereas the effect of NPs and MNPs on growth of cell suspension culture was only moderate, significant changes were detected in all other biochemical parameters. Significant changes in protein content, phytochelatins levels and GST activity were observed in BY-2 cells treated with MNPs nanoparticles treatment. Changes were also clearly evident in the case of application of NPs. Our results demonstrate the ability of MNPs to negatively affect metabolism and induce biosynthesis of protective compounds in a plant cell model represented by BY-2 cell suspension

  18. Carbon-covered magnetic nanomaterials and their application for the thermolysis of cancer cells

    Yang Xu

    2010-03-01

    Full Text Available Yang Xu1, Meena Mahmood1, Ashley Fejleh1, Zhongrui Li1, Fumiya Watanabe1, Steve Trigwell2, Reginald B Little3, Vasyl P Kunets4, Enkeleda Dervishi1, Alexandru R Biris5, Gregory J Salamo4, Alexandru S Biris11Nanotechnology Center and Applied Science Department, University of Arkansas at Little Rock, Little Rock, AR, USA; 2Applied Science and Technology, ASRC Aerospace, NASA Kennedy Space Center, FL, USA; 3Department of Chemistry, Elizabeth City State University, Elizabeth City, NC, USA; 4Physics Department, University of Arkansas, Fayetteville, AR, USA; 5National Institute for Research and Development of Isotopic and Molecular Technologies, Cluj Napoca, RomaniaAbstract: Three types of graphitic shelled-magnetic core (Fe, Fe/Co, and Co nanoparticles (named as C-Fe, C-Fe/Co, and C-Co NPs were synthesized by radio frequency-catalytic chemical vapor deposition (RF-cCVD. X-ray diffraction and X-ray photoelectron spectroscopy analysis revealed that the cores inside the carbon shells of these NPs were preserved in their metallic states. Fluorescence microscopy images indicated effective penetrations of the NPs through the cellular membranes of cultured cancer HeLa cells, both inside the cytoplasm and the nucleus. Low RF radiation of 350 kHz induced localized heating of the magnetic NPs, which triggered cell death. Apoptosis inducement was found to be dependent on the RF irradiation time and NP concentration. It was showed that the Fe-C NPs had a much higher ability of killing the cancer cells (over 99% compared with the other types of NPs (C-Co or C-Fe/Co, even at a very low concentration of 0.83 μg/mL. The localized heating of NPs inside the cancer cells comes from the hysteresis heating and resistive heating through eddy currents generated under the RF radiation. The RF thermal ablation properties of the magnetic NPs were correlated with the analysis provided by a superconducting quantum interference device (SQUID.Keywords: graphitic shelled, magnetic

  19. The interaction of sterically stabilized magnetic nanoparticles with fresh human red blood cells

    Pham BTT

    2015-10-01

    Full Text Available Binh TT Pham,1 Nirmesh Jain,1 Philip W Kuchel,2 Bogdan E Chapman,2,† Stephanie A Bickley,3 Stephen K Jones,3 Brian S Hawkett11School of Chemistry, University of Sydney, 2School of Molecular Bioscience, University of Sydney, 3Sirtex Medical Limited, Sydney, NSW, Australia†Bogdan E Chapman passed away on August 16, 2014Abstract: Sterically stabilized superparamagnetic iron oxide nanoparticles (SPIONs were incubated with fresh human erythrocytes (red blood cells [RBCs] to explore their potential application as magnetic resonance imaging contrast agents. The chemical shift and linewidth of 133Cs+ resonances from inside and outside the RBCs in 133Cs nuclear magnetic resonance spectra were monitored as a function of time. Thus, we investigated whether SPIONs of two different core sizes and with three different types of polymeric stabilizers entered metabolically active RBCs, consuming glucose at 37°C. The SPIONs broadened the extracellular 133Cs+ nuclear magnetic resonance, and brought about a small change in its chemical shift to a higher frequency; while the intracellular resonance remained unchanged in both amplitude and chemical shift. This situation pertained over incubation times of up to 90 minutes. If the SPIONs had entered the RBCs, the intracellular resonance would have become broader and possibly even shifted. Therefore, we concluded that our SPIONs did not enter the RBCs. In addition, the T2 relaxivity of the small and large particles was 368 and 953 mM-1 s-1, respectively (three and nine times that of the most effective commercially available samples. This suggests that these new SPIONs will provide a superior performance to any others reported thus far as magnetic resonance imaging contrast agents.Keywords: 133Cs NMR spectroscopy, bulk magnetic susceptibility, fresh human erythrocyte, particle stability, paramagnetic shift, superparamagnetic iron oxide nanoparticles, SPIONs

  20. Magnetically Responsive Bone Marrow Mesenchymal Stem Cell-Derived Smooth Muscle Cells Maintain Their Benefits to Augmenting Elastic Matrix Neoassembly.

    Swaminathan, Ganesh; Sivaraman, Balakrishnan; Moore, Lee; Zborowski, Maciej; Ramamurthi, Anand

    2016-04-01

    Abdominal aortic aneurysms (AAA) represent abnormal aortal expansions that result from chronic proteolytic breakdown of elastin and collagen fibers by matrix metalloproteases. Poor elastogenesis by adult vascular smooth muscle cells (SMCs) limits regenerative repair of elastic fibers, critical for AAA growth arrest. Toward overcoming these limitations, we recently demonstrated significant elastogenesis by bone marrow mesenchymal stem cell-derived SMCs (BM-SMCs) and their proelastogenesis and antiproteolytic effects on rat aneurysmal SMCs (EaRASMCs). We currently investigate the effects of super paramagnetic iron oxide nanoparticle (SPION) labeling of BM-SMCs, necessary to magnetically guide them to the AAA wall, on their functional benefits. Our results indicate that SPION-labeling is noncytotoxic and does not adversely impact the phenotype and elastogenesis by BM-SMCs. In addition, SPION-BM-SMCs showed no changes in the ability of the BM-SMCs to stimulate elastin regeneration and attenuate proteolytic activity by EaRASMCs. Together, our results are promising toward the utility of SPIONs for magnetic targeting of BM-SMCs for in situ AAA regenerative repair. PMID:26830683

  1. Magnetic Force Nanoprobe for Direct Observation of Audio Frequency Tonotopy of Hair Cells.

    Kim, Ji-Wook; Lee, Jae-Hyun; Ma, Ji-Hyun; Chung, Eunna; Choi, Hongsuh; Bok, Jinwoong; Cheon, Jinwoo

    2016-06-01

    Sound perception via mechano-sensation is a remarkably sensitive and fast transmission process, converting sound as a mechanical input to neural signals in a living organism. Although knowledge of auditory hair cell functions has advanced over the past decades, challenges remain in understanding their biomechanics, partly because of their biophysical complexity and the lack of appropriate probing tools. Most current studies of hair cells have been conducted in a relatively low-frequency range (perception of 20 kHz or higher. Here, we demonstrate that the magnetic force nanoprobe (MFN) has superb spatiotemporal capabilities to mechanically stimulate spatially-targeted individual hair cells with a temporal resolution of up to 9 μs, which is equivalent to approximately 50 kHz; therefore, it is possible to investigate avian hair cell biomechanics at different tonotopic regions of the cochlea covering a full hearing frequency range of 50 to 5000 Hz. We found that the variation of the stimulation frequency and amplitude of hair bundles creates distinct mechanical responsive features along the tonotopic axis, where the kinetics of the hair bundle recovery motion exhibits unique frequency-dependent characteristics: basal, middle, and apical hair bundles can effectively respond at their respective ranges of frequency. We revealed that such recovery kinetics possesses two different time constants that are closely related to the passive and active motilities of hair cells. The use of MFN is critical for the kinetics study of free-standing hair cells in a spatiotemporally distinct tonotopic organization. PMID:27215487

  2. Cellular Magnetic Resonance Imaging: In Vivo Imaging of Melanoma Cells in Lymph Nodes of Mice

    Paula J Foster

    2008-03-01

    Full Text Available Metastasis is responsible for most deaths due to malignant melanoma. The clinical significance of micrometastases in the lymph is a hotly debated topic, but an improved understanding of the lymphatic spread of cancer remains important for improving cancer survival. Cellular magnetic resonance imaging (MRI is a newly emerging field of imaging research that is expected to have a large impact on cancer research. In this study, we demonstrate the cellular MRI technology required to reliably image the lymphatic system in mice and to detect iron-labeled metastatic melanoma cells within the mouse lymph nodes. Melanoma cells were implanted directly into the inguinal lymph nodes in mice, and micro-MRI was performed using a customized 1.5-T clinical MRI system. We show cell detection of as few as 100 iron-labeled cells within the lymph node, with injections of larger cell numbers producing increasingly obvious regions of signal void. In addition, we show that cellular MRI allows monitoring of the fate of these cells over time as they develop into intranodal tumors. This technology will allow noninvasive investigations of cellular events in cancer metastasis within an entire animal and will facilitate progress in understanding the mechanisms of metastasis within the lymphatic system.

  3. Application of magnetic resonance imaging for monitoring stem cell transplantation for the treatment of cerebral ischemia

    Xianglin Zhang; Gang Wang; Furen Dong; Zhiming Wang

    2012-01-01

    OBJECTIVE: To identify global research trends in the application of MRI for monitoring stem cell transplantation using a bibliometric analysis of Web of Science. DATA RETRIEVAL: We performed a bibliometric analysis of studies relating to the application of MRI for detecting stem cell transplantation for the treatment of cerebral ischemia using papers in Web of Science published from 2002 to 2011. SELECTION CRITERIA: The inclusion criteria were: (a) peer-reviewed articles on the application of MRI for detecting transplanted stem cells published and indexed in Web of Science; (b) year of publication between 2002 and 2011. Exclusion criteria were: (a) articles that required manual searching or telephone access; (b) some corrected papers.MAIN OUTCOME MEASURES: (1) Annual publication output; (2) distribution according to journals; (3) distribution according to institution; (4) distribution according to country; (5) top cited authors over the last 10 years.RESULTS: A total of 1 498 studies related to the application of MRI for monitoring stem cell transplantation appeared in Web of Science from 2002 to 2011, almost half of which were derived from American authors and institutes. The number of studies on the application of MRI for detecting stem cell transplantation has gradually increased over the past 10 years. Most papers on this topic appeared in Magnetic Resonance in Medicine. CONCLUSION: This analysis suggests that few experimental studies have been investigated the use of MRI for tracking SPIO-labeled human umbilical cord blood-derived mesenchymal stem cells during the treatment of cerebral ischemia.

  4. Electroporation of cells using EM induction of ac fields by a magnetic stimulator

    This paper describes a method of effectively electroporating mammalian cell membranes with pulsed alternating-current (ac) electric fields at field strengths of 30-160 kV m-1. Although many in vivo electroporation protocols entail applying square wave or monotonically decreasing pulses via needles or electrode plates, relatively few have explored the use of pulsed ac fields. Following our previous study, which established the effectiveness of ac fields for electroporating cell membranes, a primary/secondary coil system was constructed to produce sufficiently strong electric fields by electromagnetic induction. The primary coil was formed from the applicator of an established transcranial magnetic stimulation (TMS) system, while the secondary coil was a purpose-built device of a design which could eventually be implanted into tissue. The effects of field strength, pulse interval and cumulative exposure time were investigated using microscopy and flow cytometry. Results from experiments on concentrated cell suspensions showed an optimized electroporation efficiency of around 50%, demonstrating that electroporation can be practicably achieved by inducing such pulsed ac fields. This finding confirms the possibility of a wide range of in vivo applications based on magnetically coupled ac electroporation.

  5. Quadrupole Magnet Error Sensitivities for FODO-Cell and Triplet Lattices in the LCLS Undulator

    The error sensitivities of quadrupole magnets in the LCLS FEL undulator are compared for a FODO-cell lattice and for a triplet lattice. The comparisons are made at a radiation wavelength of 1.5 (angstrom), where electron-to-photon phase errors are very sensitive to small trajectory variations in misaligned quadrupoles between the undulator sections. The results show that the triplet lattice is extremely sensitive, with triplet pitch and yaw alignment tolerances of ∼100 (micro)rad. The FODO-cell lattice, with its shorter, weaker quadrupoles is much more error tolerant with pitch and yaw tolerances of ∼2.5 mrad. Several other magnet errors are examined and categorized as trajectory, phase slip, and beam size effects. In nearly all cases, the FODO-cell lattice is much less sensitive with technologically achievable tolerance levels, while the triplet lattice tolerances are, in many cases, near achievable limits and may not be sustainable over the long term. Table 2 presents a brief tolerance comparison for the two lattice types

  6. Influence on bionomics of endothelial progenitor cells labeling with magnetic nanoparticles

    Objective: To explore the influence of home synthesize magnetic iron oxide (called Fe2O3-PLL) labeling on peripheral blood endothelial progenitor cells (EPCs) bionomics to provide experimental foundation for MR imaging ex and in vivo. Methods: Fe2O3 was incubated with PLL for 2 hours to obtain a complex of Fe2O3-PLL. Rabbit peripheral blood mononuclear cells were isolated and EPCs were selected by adherence method. Fe2O3-PLL was used to label EPCs. Prussian blue stain and electron microscope was used for showing intracellular iron. MTF assay was assessed to evaluate the difference of growth curve between unlabeled and labeled with 25 mg/L Fe2O3-PLL. Flow cytometry was performed to analyze cell cycle, cell apoptosis and the expression of surface markers of labeled and unlabeled cells. Expressions of eNOS, KDR and vWF at mRNA levels among unlabeled and labeled EPCs were detected by real-time polymerase chain reaction. Calcium ion channel and membrane fluidity were observed and analyzed by laser confocal microscopy. Statistical analyses were used with ANOVA and t test. Results: Almost 100% cells were labeled by Fe2O3-PLL, iron-containing vesicles were intracytoplasma. There was no statistical difference in cells growth curve, cell life cycle [(93.74±3.52)%, (94.57±3.66)%] and cell apoptosis rate (12.89±1.81)%, (11.67±1.18)%) between labeling with Fe2O3-PLL at a concentration of 25 mg/L and unlabeled cells (t=0.283, P>0.05; t=0.977, P>0.05). There was also no statistical difference in relative amount of eNOS, KDR and vWF at mRNA levels and the expression of surface phenotypic markers (CD34, CD106, CD146 and KDR) between two groups (P>0.05). In addition, Labeling had little influence on calcium ion channel and didn't significantly alter cell membrane fluidity. Conclusions: The rabbit peripheral blood EPCs can be effective labeled with Fe2O3-PLL and without significant influence on cells bionomics at a low concentration of 25 mg/L. Almost every cell can be labeled

  7. The use of oligoperoxide-coated magnetic nanoparticles to label stem cells

    Šponarová, Daniela; Horák, Daniel; Trchová, Miroslava; Jendelová, Pavla; Herynek, V.; Mitina, N.; Zaichenko, A.; Stoika, R.; Lesný, Petr; Syková, Eva

    2011-01-01

    Roč. 7, č. 3 (2011), s. 384-394. ISSN 1550-7033 R&D Projects: GA ČR GA203/09/1242; GA ČR GAP503/10/0664; GA MŠk 1M0538; GA AV ČR KAN201110651; GA AV ČR(CZ) KAN401220801 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z50390703 Keywords : magnetic * nanoparticles * stem cells Subject RIV: FH - Neurology Impact factor: 4.216, year: 2011

  8. The effect of magnetic field during freezing and thawing of rat bone marrow-derived mesenchymal stem cells.

    Shikata, H; Kaku, M; Kojima, S-I; Sumi, H; Kojima, S-T; Yamamoto, T; Yashima, Y; Kawata, T; Tanne, K; Tanimoto, K

    2016-08-01

    Previous studies showed that a programmed freezer with magnetic field can maintain a high survival rate of mesenchymal stem cells (MSCs). The purpose of this study was to evaluate the influences of magnetic field during freezing and thawing on the survival of MSCs isolated from rat bone marrow. The cells were frozen by a normal programmed freezer or a programmed freezer with magnetic field (CAS-LAB1) and cryopreserved for 7 days at -150 °C. Then, the cells were thawed in the presence or absence of magnetic field. Immediately after thawing, the number of surviving or viable cells was counted. The cell proliferation was examined after 1-week culture. Cryopreserved MSCs which were frozen by a normal freezer or a CAS freezer were transplanted into bone defects artificially made in calvaria of 4-week-old rats. Non-cryopreserved MSCs were used as a control. The rats were sacrificed at 8, 16, or 24 weeks after transplantation and the bone regeneration area was measured. Proliferation rates of MSCs after 1 week were significantly higher in the CAS-freezing-thawing group than in the CAS-freezing group. The extent of new bone formation in the CAS-freezing-thawing group tended to be larger than in CAS-freezing group 24 weeks after transplantation. These results suggest that a magnetic field enhances cell survival during thawing as well as freezing. PMID:27346603

  9. Enhanced magnetic resonance imaging and staining of cancer cells using ferrimagnetic H-ferritin nanoparticles with increasing core size

    Cai, Yao; Cao, Changqian; He, Xiaoqing; Yang, Caiyun; Tian, Lanxiang; Zhu, Rixiang; Pan, Yongxin

    2015-01-01

    Purpose This study is to demonstrate the nanoscale size effect of ferrimagnetic H-ferritin (M-HFn) nanoparticles on magnetic properties, relaxivity, enzyme mimetic activities, and application in magnetic resonance imaging (MRI) and immunohistochemical staining of cancer cells. Materials and methods M-HFn nanoparticles with different sizes of magnetite cores in the range of 2.7–5.3 nm were synthesized through loading different amounts of iron into recombinant human H chain ferritin (HFn) shells. Core size, crystallinity, and magnetic properties of those M-HFn nanoparticles were analyzed by transmission electron microscope and low-temperature magnetic measurements. The MDA-MB-231 cancer cells were incubated with synthesized M-HFn nanoparticles for 24 hours in Dulbecco’s Modified Eagle’s Medium. In vitro MRI of cell pellets after M-HFn labeling was performed at 7 T. Iron uptake of cells was analyzed by Prussian blue staining and inductively coupled plasma mass spectrometry. Immunohistochemical staining by using the peroxidase-like activity of M-HFn nanoparticles was carried out on MDA-MB-231 tumor tissue paraffin sections. Results The saturation magnetization (Ms), relaxivity, and peroxidase-like activity of synthesized M-HFn nanoparticles were monotonously increased with the size of ferrimagnetic cores. The M-HFn nanoparticles with the largest core size of 5.3 nm exhibit the strongest saturation magnetization, the highest peroxidase activity in immunohistochemical staining, and the highest r2 of 321 mM−1 s−1, allowing to detect MDA-MB-231 breast cancer cells as low as 104 cells mL−1. Conclusion The magnetic properties, relaxivity, and peroxidase-like activity of M-HFn nanoparticles are size dependent, which indicates that M-HFn nanoparticles with larger magnetite core can significantly enhance performance in MRI and staining of cancer cells. PMID:25878496

  10. The Effect of 217 Hz Magnetic Field of Cell Phone with Different Intensities on Apoptosis of Normal and Cancerous Cells Treated with Chemotherapy Drug

    Mahsa Mansourian

    2012-03-01

    Full Text Available Background: According to the increasing development of home and business electronic equipment in today's world, the biological effects of ELF magnetic fields have been studied at two molecular-cellular and animal- human levels. Considering the therapeutic viewpoint of this study regarding the effects of low-frequency fields of mobile phone, the effect of acute exposure to this field on chemotherapy will be studied.Materials and Methods: In this experimental study, based on measurement of the intensity of the magnetic fields from mobile phones in another research, flux densities of magnetic field of 159.44, 93.25 and 120µ tesla with frequency of 217Hz was generated in magnetic field generator system, and the apoptosis level in K562 cancer cells and healthy cells of lymphocytes was assessed after exposure to field using flow cytometry method. This evaluation method was also performed for the cells treated with bleomycin after exposure to this field.Results: 217 Hz magnetic field exposure significantly increases the rate of apoptosis percentage (p > 0.05 in K562 cancer cells and in two intensities of 120 and 159.44µ tesla compared to the control group, but such effect is not observed in lymphocyte cells. Bleomycin-induced apoptosis percentage following exposure to the mentioned magnetic field shows no significant difference compared to the group of treatment with drug and without field exposure. This lack of significant difference is observed between the groups of drug after field exposure and field alone as well as between groups exposed to field and groups treated with bleomycin.Conclusion: Study results showed that 217 Hz magnetic field of mobile phone can induce apoptosis on cancer cells, but it has no effect on healthy cells. Thus, in order to use mobile phone as an effective factor in their treatment, some studies should be conducted at animal-human level.

  11. Early effects of radiotherapy in small cell lung cancer xenografts monitored by 31P magnetic resonance spectroscopy and biochemical analysis

    Kristjansen, P E; Pedersen, E J; Quistorff, B;

    1990-01-01

    31P magnetic resonance spectroscopy (31P MRS) and biochemical analysis of extracts were applied to study the metabolic response to X-irradiation of small cell lung cancer in nude mice. Two small cell lung cancer xenografts, CPH SCCL 54A and 54B, with different radiosensitivity, although derived...

  12. Designing 3D Mesenchymal Stem Cell Sheets Merging Magnetic and Fluorescent Features: When Cell Sheet Technology Meets Image-Guided Cell Therapy

    Rahmi, Gabriel; Pidial, Laetitia; Silva, Amanda K. A.; Blondiaux, Eléonore; Meresse, Bertrand; Gazeau, Florence; Autret, Gwennhael; Balvay, Daniel; Cuenod, Charles André; Perretta, Silvana; Tavitian, Bertrand; Wilhelm, Claire; Cellier, Christophe; Clément, Olivier

    2016-01-01

    Cell sheet technology opens new perspectives in tissue regeneration therapy by providing readily implantable, scaffold-free 3D tissue constructs. Many studies have focused on the therapeutic effects of cell sheet implantation while relatively little attention has concerned the fate of the implanted cells in vivo. The aim of the present study was to track longitudinally the cells implanted in the cell sheets in vivo in target tissues. To this end we (i) endowed bone marrow-derived mesenchymal stem cells (BMMSCs) with imaging properties by double labeling with fluorescent and magnetic tracers, (ii) applied BMMSC cell sheets to a digestive fistula model in mice, (iii) tracked the BMMSC fate in vivo by MRI and probe-based confocal laser endomicroscopy (pCLE), and (iv) quantified healing of the fistula. We show that image-guided longitudinal follow-up can document both the fate of the cell sheet-derived BMMSCs and their healing capacity. Moreover, our theranostic approach informs on the mechanism of action, either directly by integration of cell sheet-derived BMMSCs into the host tissue or indirectly through the release of signaling molecules in the host tissue. Multimodal imaging and clinical evaluation converged to attest that cell sheet grafting resulted in minimal clinical inflammation, improved fistula healing, reduced tissue fibrosis and enhanced microvasculature density. At the molecular level, cell sheet transplantation induced an increase in the expression of anti-inflammatory cytokines (TGF-ß2 and IL-10) and host intestinal growth factors involved in tissue repair (EGF and VEGF). Multimodal imaging is useful for tracking cell sheets and for noninvasive follow-up of their regenerative properties. PMID:27022420

  13. Magnetic field effects on mitochondrion-activity-related optical properties in slime mold and bone forming cells.

    Mizukawa, Yuri; Iwasaka, Masakazu

    2013-01-01

    In the present study, a cellular level response of Cyto-aa3 oxidation was investigated in real time under both time-varying and strong static magnetic fields of 5 T. Two kinds of cells, a slime mold, Physarum polycephalum, and bone forming cells, MC-3T3-E1, were used for the experiments. The oxidation level of the Cyto-aa3 was calculated by optical absorptions at 690 nm, 780 nm and 830 nm. The sample, fiber-optics and an additional optical fiber for light stimulation were set in a solenoidal coil or the bore of a 5-T superconducting magnet. The solenoidal coil for time-varying magnetic fields produced sinusoidal magnetic fields of 6 mT. The slime mold showed a periodic change in Cyto-aa3 oxidation, and the oxidation-reduction cycle of Cyto-aa3 was apparently changed when visible-light irradiated the slime mold. Similarly to the case with light, time-varying magnetic stimulations changed the oxidation-reduction cycle during and after the stimulation for 10 minutes. The same phenomena were observed in the MC-3T3-E1 cell assembly, although their cycle rhythm was comparatively random. Finally, magnetic field exposure of up to 5 T exhibited a distinct suppression of Cyto-aa3 oscillation in the bone forming cells. Exposure up to 5 T was repeated five times, and the change in Cyto-aa3 oxidation reproducibly occurred. PMID:24109969

  14. Study of magnetic field to promote oxygen transfer and its application in zinc–air fuel cells

    Highlights: ► High magnetic strength reduces Rct and increases Cd in oxygen reduction reaction. ► Oxygen diffusion and transfer coefficient become large in high magnetic strength. ► The magnetic ZAFC discharge performance is better than the nonmagnetic ZAFC. ► Increased NdFeB/C load density improves the magnetic ZAFC discharge performance. ► Excess NdFeB/C load density decreases the magnetic ZAFC discharge performance. -- Abstract: This study investigates the effects of magnetic field on oxygen transfer and the correlations of electrochemical parameters in different magnetic strengths. The discharge performance of zinc–air fuel cell (ZAFC) was tested under magnetic and nonmagnetic conditions using neodymium–iron–boron/carbon (NdFeB/C) magnetic particles in ZAFC cathode. The results showed that the oxygen diffusion coefficient (DOi) and transfer coefficient (αi) increased by 102.14% and 52.38% when the magnetic strength increased from 0 mT to 5.0 mT, respectively. In addition, the electric double-layer capacitance (Cd) increased from 8.16 to 22.46 μF cm−2, the charge-transfer resistance (Rct) decreased from 9.43 Ω cm2 to 6.02 Ω cm2, and the oxygen reduction reaction (ORR) current was improved. With the NdFeB/C load density of 2.4 mg cm−2 in ZAFC cathode, the discharge current of magnetic ZAFC increased by 13.86% compared with the nonmagnetic ZAFC at the 0.80 V discharge voltage. These results indicate that magnetic strength has a positive correlation with DOi, αi, and the ORR current. Under magnetic attractions, the oxygen transfer process is easier at the Pt/C catalytic surface, and the discharge performance of magnetic ZAFC is superior to the nonmagnetic ZAFC. At lower NdFeB/C load density, increasing the NdFeB/C load density facilitates oxygen transfer and improves the discharge performance of ZAFC. However, the magnetic ZAFC discharge performance decreases at a higher NdFeB/C load density because of the blocked oxygen transfer channel

  15. Nanoparticle encapsulation in red blood cells enables blood-pool magnetic particle imaging hours after injection

    Magnetic particle imaging (MPI) is a new medical imaging approach that is based on the nonlinear magnetization response of super-paramagnetic iron oxide nanoparticles (SPIOs) injected into the blood stream. To date, real-time MPI of the bolus passage of an approved MRI SPIO contrast agent injected into the tail vein of living mice has been demonstrated. However, nanoparticles are rapidly removed from the blood stream by the mononuclear phagocyte system. Therefore, imaging applications for long-term monitoring require the repeated administration of bolus injections, which complicates quantitative comparisons due to the temporal variations in concentration. Encapsulation of SPIOs into red blood cells (RBCs) has been suggested to increase the blood circulation time of nanoparticles. This work presents first evidence that SPIO-loaded RBCs can be imaged in the blood pool of mice several hours after injection using MPI. This finding is supported by magnetic particle spectroscopy performed to quantify the iron concentration in blood samples extracted from the mice 3 and 24 h after injection of SPIO-loaded RBCs. Based on these results, new MPI applications can be envisioned, such as permanent 3D real-time visualization of the vessel tree during interventional procedures, bleeding monitoring after stroke, or long-term monitoring and treatment control of cardiovascular diseases. (paper)

  16. Magnetic resonance imaging of thickened pituitary stalk proceeding to langerhans cell histiocytosis in a child

    Magnetic resonance imaging has shown isolated pituitary stalk thickening in certain cases of idiopathic or secondary central diabetes insipidus (Dl) due to infiltrative processes. We present a 4-year-old boy who was initially diagnosed as having central Dl. The MRI showed isolated pituitary stalk thickening with prominent homogeneous contrast enhancement. The remaining findings on MRI were within normal limits. The patient's personal and family history and laboratory and clinical findings were unremarkable; therefore, he was initially diagnosed as having idiopathic Dl. Since central Dl and isolated pituitary stalk thickening may be considered to be the first manifestations of Langerhans cell histiocytosis, we decided to follow up the patient. After 5 months, following the initial diagnosis, on skeletal X-ray survey, the patient did indeed develop multiple lytic skull lesions which, on biopsy, were histologically typical bone lesions of Langerhans cell histiocytosis. Copyright (2006) Blackwell Science Pty Ltd

  17. A sup 1 H nuclear magnetic resonance study of structural and organisational changes in the cell

    Tunnah, S K

    2000-01-01

    Increasing importance is being placed on understanding the role of membrane lipids in many different areas of biochemistry. It is of interest to determine what interactions may occur between membrane lipids and drug species. Furthermore, an increasing body of evidence suggests that membrane lipids are involved in the pathology of numerous diseases such as rheumatoid arthritis, cancer and HIV. Clearly, the more information available on the mechanisms involved in diseases, the greater the potential for identifying a cure or even a prevention. sup 1 H nuclear magnetic resonance (NMR) spectroscopy was used to study the alterations in membrane lipid organisation and structure in intact, viable cultured cells. Changes in the sup 1 H NMR spectra and the spin-lattice relaxation measurements of the human K562 and the rat FRTL-5 cell lines were observed on the addition of the fatty acid species: triolein, evening primrose oil, arachidonic acid and ITF 1779. Results indicate that the membrane lipids are reorganised to a...

  18. Physics of a magnetic barrier in low-temperature bounded plasmas: insight from particle-in-cell simulations

    The use of magnetic fields is quite common in low-pressure, low-temperature, gas-discharge devices for industrial applications. However, transport in such devices is still not very well clarified, mainly due to the presence of walls playing a crucial role and to the variety of configurations studied. The latter often obstruct the underlying basic physical phenomena and make the different studies valid only for very specific configurations. This work presents a numerical study of particle transport in low-pressure (0.3 Pa) plasmas across a localized transverse magnetic field (magnetic barrier) by means of the 2D3V particle-in-cell with Monte Carlo collisions method. The problem is treated as generally as possible while trying to reveal the basic physics, using very simplified chemistry and considering a simple rectangular configuration. The conditions chosen for the magnetic field are common to many applications—magnetized electrons and almost unmagnetized ions. Two basic configurations with different magnetic field directions are analyzed in detail: magnetic field perpendicular to the simulation plane and along the simulation plane. An extensive parametric study is carried out in order to obtain the main trends and scaling laws for particle transport with respect to different parameters: plasma density, magnetic barrier size and magnetic field magnitude. The total current of electrons crossing the barrier is found to scale linearly with the plasma density, which extends the validity of the obtained results to a wide range of plasma density values. (paper)

  19. In vivo MR tracking of magnetically labeled mesenchymal stem cells in rat liver after intrasplenic transplantation

    Objective: To evaluate the 1.5-T magnetic resonance imaging system to depict and track in vivo of magnetically labeled bone mesenchymal stem cells (BMSCs) in rat liver after intrasplenic transplantation. Methods: Rat BMSCs were isolated, purified, expanded and then incubated with home synthesized Fe2O3-PLL. Prussian blue stain was performed for showing intracellular irons. Acute liver damage was induced by subcutaneous injection of carbon tetrachloride in 12 recipient rats. The cells allotransplantation was performed by intrasplenic injection with magnetically labeled (experimental group, n=6) or unlabeled BMSCs (control group, n=6). Serial MRI were performed before and 3 hours, 3, 7, 14 days after transplantation. Signal-to-noise ratio (SNR) of liver on T2*-weighted MR imaging obtained before and after injection were measured and compared. MR imaging findings were compared histologically with histology. Results: Rats BMSCs could be effectively labeled and the labeling efficiency was almost 100%. Iron-containing intracytoplasmatic vesicles could be observed clearly with prussian blue staining. SNR of rat livers in experimental group and control group before and 3 hours, 3, 7, 14 days after transplantation were 19.53±2.30, 3.28±1.06, 7.34±2.10, 10.25±3.96, 15.50±3.73; 20.20±4.35, 21.20±4.43, 19.13±2.80, 21.43±5.45, 19.07±4.80, respectively. SNR decreased significantly in the experimental group liver 3 hours, 3, 7 days after injection of BMSCs (Dunnett test, P0.05). In control group, SNR demonstrated no significant differences among different time points (ANOVA, P>0.05). Results of histological analysis confirmed homing of labeled BMSCs in liver, primarily distributing in areas around centrolobular vein. Conclusion: The BMSCs can be effectively labeled with Fe2O3-PLL. 1.5-T MR imaging can monitor in vivo of magnetically labeled BMSCs in liver after intrasplenic transplantation. It potentially opens a new area of investigation for delivering stem cells

  20. Genotoxic effects of 50 Hz magnetic fields on human blood cells

    Full text: The possible health hazard of exposure to extremely low frequency magnetic fields (ELFMFs) has became an issue of considerable public concern. Although many epidemiological studies have been done, a definite correlation between exposure to environmental ELFMFs and cancer has not been found.. According to several investigations, ELF fields cannot directly damage DNA or cause mutations (NRPB,1992; Verschaeve 1995). On the other hand few studies have addressed the possibility that ELF magnetic fields could be able to enhance the genotoxic effect of known chemical or physical mutagens (Hintenlang, 1993; Maes et al., 2000). The aim of the present study is to investigate the potential genotoxic effect of ELFMFs alone or in combination with X rays on human blood cells. Four different cytogenetic tests (chromosome aberration, cytokinesis-block micronucleus, sister chromatid exchange and comet assay) have been applied. Human blood samples were exposed to 50 Hz, 1 mT uniform magnetic field generated by a Helmholtz coil system, in incubator. Whole blood samples from three healthy donors (30-40 years) were exposed to ELF MFs for 2 h and further blood samples from other three donors were diluted in culture medium in absence of phytoemoagglutinin and then exposed for 48 h to ELF fields. A sham control consisting on a same current system, with the coils activated in anti-parallel direction was used. A positive control (1 Gy of X-rays) were also included. A potential synergistic effect between ELF and X-rays (1 Gy) exposures was also investigated. Results did not show any significant differences between 2 h ELFMFs-exposed and unexposed samples for each cytogenetic endpoints analyzed. Similarly, the combined treatments failed to indicate the presence of any synergistic effect between the ELF magnetic fields and the physical mutagen. Results from the 48 h exposure time are currently being processed. (author)

  1. Impedance spectroscopy assisted by magnetic nanoparticles as a potential biosensor principle for breast cancer cells in suspension

    Breast cancer (BC) is the leading cause of cancer death in women worldwide, with a higher mortality reported in undeveloped countries. Ideal adjuvant therapeutic strategies require the continuous monitoring of patients by regular blood tests to detect circulating cancer cells, in order to determine whether additional treatment is necessary to prevent cancer dissemination. This circumstance requires a non-complex design of tumor cell biosensor in whole blood with feasibility for use in poor regions. In this work we have evaluated an inexpensive and simple technique of relative bioimpedance measurement, assisted by magnetic nanoparticles, as a potential biosensor of BC cells in suspension. Measurements represent the relative impedance changes caused by the magnetic holding of an interphase of tumor cells versus a homogenous condition in the frequency range of 10–100 kHz. The results indicate that use of a magnet to separate tumor cells in suspension, coupled to magnetic nanoparticles, is a feasible technique to fix an interphase of tumor cells in close proximity to gold electrodes. Relative impedance changes were shown to have potential value as a biosensor method for BC cells in whole blood, at frequencies around 20 kHz. Additional studies are warranted with respect to electrode design and sensitivity at micro-scale levels, according to the proposed technique. (paper)

  2. Quantitative Magnetic Particle Imaging Monitors the Transplantation, Biodistribution, and Clearance of Stem Cells In Vivo

    Zheng, Bo; von See, Marc P.; Yu, Elaine; Gunel, Beliz; Lu, Kuan; Vazin, Tandis; Schaffer, David V.; Goodwill, Patrick W.; Conolly, Steven M.

    2016-01-01

    Stem cell therapies have enormous potential for treating many debilitating diseases, including heart failure, stroke and traumatic brain injury. For maximal efficacy, these therapies require targeted cell delivery to specific tissues followed by successful cell engraftment. However, targeted delivery remains an open challenge. As one example, it is common for intravenous deliveries of mesenchymal stem cells (MSCs) to become entrapped in lung microvasculature instead of the target tissue. Hence, a robust, quantitative imaging method would be essential for developing efficacious cell therapies. Here we show that Magnetic Particle Imaging (MPI), a novel technique that directly images iron-oxide nanoparticle-tagged cells, can longitudinally monitor and quantify MSC administration in vivo. MPI offers near-ideal image contrast, depth penetration, and robustness; these properties make MPI both ultra-sensitive and linearly quantitative. Here, we imaged, for the first time, the dynamic trafficking of intravenous MSC administrations using MPI. Our results indicate that labeled MSC injections are immediately entrapped in lung tissue and then clear to the liver within one day, whereas standard iron oxide particle (Resovist) injections are immediately taken up by liver and spleen. Longitudinal MPI-CT imaging also indicated a clearance half-life of MSC iron oxide labels in the liver at 4.6 days. Finally, our ex vivo MPI biodistribution measurements of iron in liver, spleen, heart, and lungs after injection showed excellent agreement (R2 = 0.943) with measurements from induction coupled plasma spectrometry. These results demonstrate that MPI offers strong utility for noninvasively imaging and quantifying the systemic distribution of cell therapies and other therapeutic agents. PMID:26909106

  3. Prenatal diagnosis from maternal blood: simultaneous immunophenotyping and FISH of fetal nucleated erythrocytes isolated by negative magnetic cell sorting.

    Zheng, Y.L.; Carter, N. P.; Price, C M; Colman, S. M.; Milton, P J; Hackett, G A; Greaves, M F; Ferguson-Smith, M A

    1993-01-01

    Fetal nucleated cells in the maternal circulation constitute a potential source of cells for the non-invasive prenatal diagnosis of fetal genetic abnormalities. We have investigated the use of the Magnetic Activated Cell Sorter (MACS) for enriching fetal nucleated erythrocytes. Mouse monoclonal antibodies specific for CD45 and CD32 were used to deplete leucocytes from maternal blood using MACS sorting, thus enriching for fetal nucleated erythrocytes which do not express either of these antige...

  4. Magnetic resonance imaging of single co-labeled mesenchymal stromal cells after intracardial injection in mice

    Purpose: The aim of this study was to establish co-labeling of mesenchymal stromal cells (MSC) for the detection of single MSC in-vivo by MRI and histological validation. Materials and Methods: Mouse MSC were co-labeled with fluorescent iron oxide micro-particles and carboxyfluorescein succinimidyl ester (CFSE). The cellular iron content was determined by atomic absorption spectrometry. Cell proliferation and expression of characteristic surface markers were determined by flow cytometry. The chondrogenic differentiation capacity was assessed. Different amounts of cells (n1 = 5000, n2 = 15 000, n3 = 50 000) were injected into the left heart ventricle of 12 mice. The animals underwent sequential MRI on a clinical 3.0T scanner (Intera, Philips Medical Systems, Best, The Netherlands). For histological validation cryosections were examined by fluorescent microscopy. Results: Magnetic and fluorescent labeling of MSC was established (mean cellular iron content 23.6 ± 3 pg). Flow cytometry showed similar cell proliferation and receptor expression of labeled and unlabeled MSC. Chondrogenic differentiation of labeled MSC was verified. After cell injection MRI revealed multiple signal voids in the brain and fewer signal voids in the kidneys. In the brain, an average of 4.6 ± 1.2 (n1), 9.0 ± 3.6 (n2) and 25.0 ± 1.0 (n3) signal voids were detected per MRI slice. An average of 8.7 ± 3.1 (n1), 22.0 ± 6.1 (n2) and 89.8 ± 6.5 (n3) labeled cells per corresponding stack of adjacent cryosections could be detected in the brain. Statistical correlation of the numbers of MRI signal voids in the brain and single MSC found by histology revealed a correlation coefficient of r = 0.91. Conclusion: The study demonstrates efficient magnetic and fluorescent co-labeling of MSC and their detection on a single cell level in mice by in-vivo MRI and histology. The described techniques may broaden the methods for in-vivo tracking of MSC. (orig.)

  5. Magnetic resonance imaging of single co-labeled mesenchymal stromal cells after intracardial injection in mice

    Salamon, J.; Adam, G.; Peldschus, K. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Diagnostic and Interventional Radiology; Wicklein, D.; Schumacher, U. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Inst. of Anatomy II: Experimental Morphology; Didie, M. [Goettingen Univ. (Germany). Inst. of Pharmacology; Lange, C. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Bone Marrow Transplantation

    2014-04-15

    Purpose: The aim of this study was to establish co-labeling of mesenchymal stromal cells (MSC) for the detection of single MSC in-vivo by MRI and histological validation. Materials and Methods: Mouse MSC were co-labeled with fluorescent iron oxide micro-particles and carboxyfluorescein succinimidyl ester (CFSE). The cellular iron content was determined by atomic absorption spectrometry. Cell proliferation and expression of characteristic surface markers were determined by flow cytometry. The chondrogenic differentiation capacity was assessed. Different amounts of cells (n1 = 5000, n2 = 15 000, n3 = 50 000) were injected into the left heart ventricle of 12 mice. The animals underwent sequential MRI on a clinical 3.0T scanner (Intera, Philips Medical Systems, Best, The Netherlands). For histological validation cryosections were examined by fluorescent microscopy. Results: Magnetic and fluorescent labeling of MSC was established (mean cellular iron content 23.6 ± 3 pg). Flow cytometry showed similar cell proliferation and receptor expression of labeled and unlabeled MSC. Chondrogenic differentiation of labeled MSC was verified. After cell injection MRI revealed multiple signal voids in the brain and fewer signal voids in the kidneys. In the brain, an average of 4.6 ± 1.2 (n1), 9.0 ± 3.6 (n2) and 25.0 ± 1.0 (n3) signal voids were detected per MRI slice. An average of 8.7 ± 3.1 (n1), 22.0 ± 6.1 (n2) and 89.8 ± 6.5 (n3) labeled cells per corresponding stack of adjacent cryosections could be detected in the brain. Statistical correlation of the numbers of MRI signal voids in the brain and single MSC found by histology revealed a correlation coefficient of r = 0.91. Conclusion: The study demonstrates efficient magnetic and fluorescent co-labeling of MSC and their detection on a single cell level in mice by in-vivo MRI and histology. The described techniques may broaden the methods for in-vivo tracking of MSC. (orig.)

  6. Fluorescent magnetic nanoparticles for cell labeling: flux synthesis of manganite particles and novel functionalization of silica shell

    Kačenka, Michal; Kaman, Ondřej; Kikerlová, S.; Pavlů, B.; Jirák, Zdeněk; Jirák, D.; Herynek, Vít; Černý, J.; Chaput, F.; Laurent, S.; Lukeš, I.

    2015-01-01

    Roč. 47, Jun (2015), s. 97-106. ISSN 0021-9797 R&D Projects: GA ČR(CZ) GAP108/11/0807; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:68378271 ; RVO:68378041 Keywords : manganites * magnetic nanoparticles * molten salt synthesis * silica coating * dual probes * MRI * cell labeling Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.368, year: 2014

  7. Enhanced magnetic resonance imaging and staining of cancer cells using ferrimagnetic H-ferritin nanoparticles with increasing core size

    Cai Y

    2015-04-01

    Full Text Available Yao Cai,1–3 Changqian Cao,1,2 Xiaoqing He,1 Caiyun Yang,1–3 Lanxiang Tian,1,2 Rixiang Zhu,2 Yongxin Pan1,21France–China Bio-Mineralization and Nano-Structures Laboratory, 2Paleomagnetism and Geochronology Laboratory, Key Laboratory of the Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, 3University of Chinese Academy of Sciences, Beijing, People’s Republic of ChinaPurpose: This study is to demonstrate the nanoscale size effect of ferrimagnetic H-ferritin (M-HFn nanoparticles on magnetic properties, relaxivity, enzyme mimetic activities, and application in magnetic resonance imaging (MRI and immunohistochemical staining of cancer cells.Materials and methods: M-HFn nanoparticles with different sizes of magnetite cores in the range of 2.7–5.3 nm were synthesized through loading different amounts of iron into recombinant human H chain ferritin (HFn shells. Core size, crystallinity, and magnetic properties of those M-HFn nanoparticles were analyzed by transmission electron microscope and low-temperature magnetic measurements. The MDA-MB-231 cancer cells were incubated with synthesized M-HFn nanoparticles for 24 hours in Dulbecco’s Modified Eagle’s Medium. In vitro MRI of cell pellets after M-HFn labeling was performed at 7 T. Iron uptake of cells was analyzed by Prussian blue staining and inductively coupled plasma mass spectrometry. Immunohistochemical staining by using the peroxidase-like activity of M-HFn nanoparticles was carried out on MDA-MB-231 tumor tissue paraffin sections.Results: The saturation magnetization (Ms, relaxivity, and peroxidase-like activity of synthesized M-HFn nanoparticles were monotonously increased with the size of ferrimagnetic cores. The M-HFn nanoparticles with the largest core size of 5.3 nm exhibit the strongest saturation magnetization, the highest peroxidase activity in immunohistochemical staining, and the highest r2 of 321 mM-1 s-1, allowing to

  8. Critical analysis of data concerning Saccharomyces cerevisiae free-cell proliferations and fermentations assisted by magnetic and electromagnetic fields

    Hristov, Jordan

    2011-01-01

    The review analyses studies on magnetically assisted proliferations and batch fermentations with Saccharomyces cerevisiae yeasts. The results available in the literature are contradictory and show two tendencies: magnetic field suppression of the cell growth and positive effects in batch fermentation with increasing both biomass and metabolite production. The amount of data analyzed allows several concepts existing in the literature to be outlined and critically commented. Further, a new concept of magnetically induced micro-dynamos, recently conceived, is developed towards a unified explanation of the results provided by proliferation and batch fermentation experiments

  9. Study on performance of magnetic fluorescent nanoparticles as gene carrier and location in pig kidney cells

    Wang, Yan; Cui, Haixin; Sun, Changjiao; Du, Wei; Cui, Jinhui; Zhao, Xiang

    2013-03-01

    We evaluated the performance of green fluorescent magnetic Fe3O4 nanoparticles (NPs) as gene carrier and location in pig kidney cells. When the mass ratio of NPs to green fluorescent protein plasmid DNA reached 1:16 or above, DNA molecules can be combined completely with NPs, which indicates that the NPs have good ability to bind negative DNA. Atomic force microscopy (AFM) experiments were carried out to investigate the binding mechanism between NPs and DNA. AFM images show that individual DNA strands come off of larger pieces of netlike agglomerations and several spherical nanoparticles are attached to each individual DNA strand and interact with each other. The pig kidney cells were labelled with membrane-specific red fluorescent dye 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate and nucleus-specific blue fluorescent dye 4',6-diamidino-2-phenylindole dihydrochloride. We found that green fluorescent nanoparticles can past the cell membrane and spread throughout the interior of the cell. The NPs seem to locate more frequently in the cytoplasm than in the nucleus.

  10. Investigation of stroke in sickle cell disease by 1H nuclear magnetic resonance spectroscopy

    Localized proton nuclear magnetic resonance spectroscopy (MRS), obtained with stimulated echo and spin echo sequences, MR imaging (MRI) and MR angiography (MRA) were used to study the brain in 13 children and adolescents with sickle cell disease. Regions of interest (ROI) studied by MRS included regions appearing normal on MRI as well as regions showing complications of sickle cell disease, including focal deep white matter areas of high signal intensity (deep white matter ischemia, DWMI) seen on long TR images, focal atropic brain areas, and infarcts. The findings in these studies are summarized as follows: Normal-appearing regions on MRI have normal MRS. In ROI including small areas of DWMI, lactate elevation was not detected, but the levels of N-acetyl-aspartate (NAA) appeared slightly elevated. In areas of DWMI 1-2 cm in size, reduced blood flow could be seen on MRA and lactate elevation could be detected with MRS. When blood flow to a DWMI region was normal, NAA was reduced and there was little lactate elevation, as cell death had already occurred. ROI consisting of atrophic tissue had reduced NAA levels but total creatine levels were not changed. Sometimes lipids, presumably from broken cell membrane, could be detected. In regions of past massive stroke, all metabolites were absent except for small amounts of lactate or lipids. (orig.)

  11. Surface engineered magnetic nanoparticles for specific immunotargeting of cadherin expressing cells

    Moros, Maria; Delhaes, Flavien; Puertas, Sara; Saez, Berta; de la Fuente, Jesús M.; Grazú, Valeria; Feracci, Helene

    2016-02-01

    In spite of historic advances in cancer biology and recent development of sophisticated chemotherapeutics, the outlook for patients with advanced cancer is still grim. In this sense nanoparticles (NPs), through their unique physical properties, enable the development of new approaches for cancer diagnosis and treatment. Thus far the most used active targeting scheme involves NPs functionalization with antibodies specific to molecules overexpressed on cancer cell’s surface. Therefore, such active targeting relies on differences in NPs uptake kinetics rates between tumor and healthy cells. Many cancers of epithelial origin are associated with the inappropriate expression of non-epithelial cadherins (e.g. N-, P-, -11) with concomitant loss of E-cadherin. Such phenomenon named cadherin switching favors tumor development and metastasis via interactions of tumor cells with stromal components. That is why we optimized the oriented functionalization of fluorescently labelled magnetic NPs with a novel antibody specific for the extracellular domain of cadherin-11. The obtained Ab-NPs exhibited high specificity when incubated with two cell lines used as models of tumor and healthy cells. Thus, cadherin switching offers a great opportunity for the development of active targeting strategies aimed to improve the early detection and treatment of cancer.

  12. Multiparametric magnetic resonance imaging for the differentiation of low and high grade clear cell renal carcinoma

    To retrospectively evaluate the ability of magnetic resonance (MR) imaging to differentiate low from high Fuhrman grade renal cell carcinoma (RCC). MR images from 80 consecutive pathologically proven RCC (57 clear cell, 16 papillary and 7 chromophobe) were evaluated. Double-echo chemical shift, dynamic contrast-enhanced T1- and T2-weighted images and apparent diffusion coefficient (ADC) maps were reviewed independently. Signal intensity index (SII), tumour-to-spleen SI ratio (TSR), ADC ratio, wash-in (WiI) and wash-out indices (WoI) between different phases were calculated and compared to pathological grade and size. The Fuhrman scoring system was used. Low grade (score ≤2) and high grade (score ≥3) tumours were compared using univariate and multivariate analyses. No associations between grade and imaging factors were found for papillary and chromophobe RCCs. For clear cell RCCs, there was a significant association between the grade and parenchymal WiI (WiI2) (P = 0.02) or ADCr (P = 0.03). A significant association between tumour grade and size (P = 0.01), WiI2 (P = 0.02) and ADCr (P = 0.05) remained in multivariate analysis. Multiparametric MRI can be used to accurately differentiate low Fuhrman grade clear cell RCC from high grade. High Fuhrman grade (≥3) RCCs were larger, had lower parenchymal wash-in indices and lower ADC ratios than low grade. (orig.)

  13. Quantitative imaging of cell-permeable magnetic resonance contrast agents using x-ray fluorescence.

    Endres, Paul J; Macrenaris, Keith W; Vogt, Stefan; Allen, Matthew J; Meade, Thomas J

    2006-01-01

    The inability to transduce cellular membranes is a limitation of current magnetic resonance imaging probes used in biologic and clinical settings. This constraint confines contrast agents to extracellular and vascular regions of the body, drastically reducing their viability for investigating processes and cycles in developmental biology. Conversely, a contrast agent with the ability to permeate cell membranes could be used in visualizing cell patterning, cell fate mapping, gene therapy, and, eventually, noninvasive cancer diagnosis. Therefore, we describe the synthesis and quantitative imaging of four contrast agents with the capability to cross cell membranes in sufficient quantity for detection. Each agent is based on the conjugation of a Gd(III) chelator with a cellular transduction moiety. Specifically, we coupled Gd(III)-diethylenetriaminepentaacetic acid DTPA and Gd(III)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid with an 8-amino acid polyarginine oligomer and an amphipathic stilbene molecule, 4-amino-4'-(N,N-dimethylamino)stilbene. The imaging modality that provided the best sensitivity and spatial resolution for direct detection of the contrast agents is synchrotron radiation x-ray fluorescence (SR-XRF). Unlike optical microscopy, SR-XRF provides two-dimensional images with resolution 10(3) better than (153)Gd gamma counting, without altering the agent by organic fluorophore conjugation. The transduction efficiency of the intracellular agents was evaluated by T(1) analysis and inductively coupled plasma mass spectrometry to determine the efficacy of each chelate-transporter combination. PMID:17150161

  14. Extra-Low-Frequency Magnetic Fields alter Cancer Cells through Metabolic Restriction

    Li, Ying

    2012-01-01

    Background: Biological effects of extra-low-frequency (ELF) magnetic fields (MF) have lacked a credible mechanism of interaction between MFs and living material. Objectives: Examine the effect of ELF-MFs on cancer cells. Methods: Five cancer cell lines were exposed to ELF-MFs within the range of 0.025 to 5 microT, and the cells were examined for karyotype changes after 6 days. Results: All cancer cells lines lost chromosomes from MF exposure, with a mostly flat dose-response. Constant MF exposures for three weeks allow a rising return to the baseline, unperturbed karyotypes. From this point, small MF increases or decreases are again capable of inducing karyotype contractions. Our data suggests that the karyotype contractions are caused by MF interference with mitochondria's ATP synthase (ATPS), compensated by the action of AMP-activated Protein Kinase (AMPK). The effects of MFs are similar to those of the ATPS inhibitor oligomycin. They are amplified by metformin, an AMPK stimulator, and attenuated by resisti...

  15. Multiparametric magnetic resonance imaging for the differentiation of low and high grade clear cell renal carcinoma

    Cornelis, F.; Tricaud, E.; Lasserre, A.S.; Petitpierre, F.; Le Bras, Y.; Bouzgarrou, M.; Grenier, N. [Pellegrin Hospital, Department of Radiology, Bordeaux (France); Bernhard, J.C. [Pellegrin Hospital, Department of Urology, Bordeaux (France); Yacoub, M. [Pellegrin Hospital, Department of Pathology, Bordeaux (France); Ravaud, A. [Saint-Andre Hospital, Department of Oncology, Bordeaux (France)

    2015-01-15

    To retrospectively evaluate the ability of magnetic resonance (MR) imaging to differentiate low from high Fuhrman grade renal cell carcinoma (RCC). MR images from 80 consecutive pathologically proven RCC (57 clear cell, 16 papillary and 7 chromophobe) were evaluated. Double-echo chemical shift, dynamic contrast-enhanced T1- and T2-weighted images and apparent diffusion coefficient (ADC) maps were reviewed independently. Signal intensity index (SII), tumour-to-spleen SI ratio (TSR), ADC ratio, wash-in (WiI) and wash-out indices (WoI) between different phases were calculated and compared to pathological grade and size. The Fuhrman scoring system was used. Low grade (score ≤2) and high grade (score ≥3) tumours were compared using univariate and multivariate analyses. No associations between grade and imaging factors were found for papillary and chromophobe RCCs. For clear cell RCCs, there was a significant association between the grade and parenchymal WiI (WiI2) (P = 0.02) or ADCr (P = 0.03). A significant association between tumour grade and size (P = 0.01), WiI2 (P = 0.02) and ADCr (P = 0.05) remained in multivariate analysis. Multiparametric MRI can be used to accurately differentiate low Fuhrman grade clear cell RCC from high grade. High Fuhrman grade (≥3) RCCs were larger, had lower parenchymal wash-in indices and lower ADC ratios than low grade. (orig.)

  16. Effects of ELF magnetic fields on protein expression profile of human breast cancer cell MCF7

    LI Han; ZENG Qunli; WENG Yu; LU Deqiang; JIANG Huai; XU Zhengping

    2005-01-01

    Extremely Low Frequency Magnetic Fields (ELF MF) has been considered as a "possible human carcinogen" by International Agency for Research on Cancer (IARC) while credible mechanisms of its carcinogenicity remain unknown. In this study, a proteomics approach was employed to investigate the changes of protein expression profile induced by ELF MF in human breast cancer cell line MCF7, in order to determine ELF MF-responsive proteins. MCF7 cells were exposed to 50 Hz, 0.4 mT ELF MF for 24 h and the changes of protein profile were examined using two dimensional electrophoresis. Up to 6 spots have been statistically significantly altered (their expression levels were changed at least 5 fold up or down) compared with sham-exposed group. 19 ones were only detected in exposure group while 19 ones were missing. Three proteins were identified by LC-IT Tandem MS as RNA binding protein regulatory subunit、Proteasome subunit beta type 7 precursor and Translationally Controlled Tumor Protein. Our finding showed that 50 Hz, 0.4 mT ELF MF alternates the protein profile of MCF7 cell and may affect many physiological functions of normal cell and 2-DE coupled with MS is a promising approach to elucidating cellular effects of electromagnetic fields.

  17. Trapping and dynamic manipulation of polystyrene beads mimicking circulating tumor cells using targeted magnetic/photoacoustic contrast agents

    Wei, Chen-Wei; Xia, Jinjun; Pelivanov, Ivan; Hu, Xiaoge; Gao, Xiaohu; O'Donnell, Matthew

    2012-10-01

    Results on magnetically trapping and manipulating micro-scale beads circulating in a flow field mimicking metastatic cancer cells in human peripheral vessels are presented. Composite contrast agents combining magneto-sensitive nanospheres and highly optical absorptive gold nanorods were conjugated to micro-scale polystyrene beads. To efficiently trap the targeted objects in a fast stream, a dual magnet system consisting of two flat magnets to magnetize (polarize) the contrast agent and an array of cone magnets producing a sharp gradient field to trap the magnetized contrast agent was designed and constructed. A water-ink solution with an optical absorption coefficient of 10 cm-1 was used to mimic the optical absorption of blood. Magnetomotive photoacoustic imaging helped visualize bead trapping, dynamic manipulation of trapped beads in a flow field, and the subtraction of stationary background signals insensitive to the magnetic field. The results show that trafficking micro-scale objects can be effectively trapped in a stream with a flow rate up to 12 ml/min and the background can be significantly (greater than 15 dB) suppressed. It makes the proposed method very promising for sensitive detection of rare circulating tumor cells within high flow vessels with a highly absorptive optical background.

  18. Characterization of Iron-Oxide Loaded Adult Stem Cells for Magnetic Particle Imaging in Targeted Cancer Therapy

    Lüdtke-Buzug, Kerstin; Rapoport, Daniel Hans; Schneider, Dagmar

    2010-12-01

    Recently, magnetic particle imaging (MPI) has been presented as a new method for the measurement of the spatial distribution of superparamagnetic iron oxide nanoparticles (SPIONs). MPI is based on the nonlinear magnetization response of nanoparticles that are subjected to a sinusoidal magnetic field. Spatial resolution and signal to noise ratio of MPI depend on the particle quality. This is particularly important when stem cells shall be tracked with MPI. Stem cell-based treatment is an upcoming technology in targeted cancer-therapy. In this study, we analyzed the particle quality of newly developed dextran-coated SPIONs—with respect to their response in the imaging experiment—using magnetic particle spectrometry. The uptake of dextran-coated SPIONs into rat and human adult stem cells was monitored via transmission electron microscopy. Furthermore, adult stem cells were incubated with FITC-dextran-coated SPIONs and stained for confocal laser scanning microscopy. The dextran- and FITC-dextran coated SPIONs were localized in the cytoplasm of rat and human adult stem cells. MPI promises real-time imaging with high spatial resolution at high sensitivity. Our data support iron oxide loaded adult stem cells as a powerful tool for targeted cancer therapy.

  19. Folic acid conjugated magnetic iron oxide nanoparticles for nondestructive separation and detection of ovarian cancer cells from whole blood.

    Liu, Wenting; Nie, Liju; Li, Fulai; Aguilar, Zoraida P; Xu, Hong; Xiong, Yonghua; Fu, Fen; Xu, Hengyi

    2016-01-01

    Because of the lack of early screening strategies, ovarian cancer is the most deadly cause of gynecologic malignancies. This paper describes an effective method for the separation and detection of ovarian cancer cells from female whole blood, using folic acid (FA) conjugated magnetic iron oxide nanoparticles (IO-FA nanoparticles). The IO nanoparticles were synthesized by thermal decomposition and then covalently conjugated with FA. The IO-FA nanoparticles were stably attached to the surface of ovarian cancer cells by coupling to the over-expressed folate receptor (FR), thereby making the cells magnetic. These "magnetic cells" were separated from the complex blood matrix without destruction under a magnetic field. The separation efficiency was as high as 61.3% when the abundance of spiked ovarian cancer SKOV3 cells was as low as 5 × 10(-5)%. We also successfully detected five (5) out of ten (10) metastatic ovarian cancer patients' whole blood. This study suggested the feasibility of early detecting of metastatic ovarian cancer cells, which may potentially improve the ovarian cancers patients' overall survival rate for clinical applications. PMID:26478922

  20. Mannose-functionalized porous silica-coated magnetic nanoparticles for two-photon imaging or PDT of cancer cells

    Perrier, Marine [UMR 5253 CNRS-UM2-ENSCM-UM1, Institut Charles Gerhardt Montpellier (France); Gary-Bobo, Magali [Faculte de Pharmacie, Universite Montpellier 1, Universite Montpellier 2, Institut des Biomolecules Max Mousseron UMR 5247 CNRS (France); Lartigue, Lenaiec; Brevet, David [UMR 5253 CNRS-UM2-ENSCM-UM1, Institut Charles Gerhardt Montpellier (France); Morere, Alain; Garcia, Marcel [Faculte de Pharmacie, Universite Montpellier 1, Universite Montpellier 2, Institut des Biomolecules Max Mousseron UMR 5247 CNRS (France); Maillard, Philippe [Universite Paris-Sud, UMR 176 CNRS, Institut Curie (France); Raehm, Laurence; Guari, Yannick, E-mail: yannick.guari@um2.fr; Larionova, Joulia; Durand, Jean-Olivier, E-mail: durand@univ-montp2.fr [UMR 5253 CNRS-UM2-ENSCM-UM1, Institut Charles Gerhardt Montpellier (France); Mongin, Olivier [Universite de Rennes 1, Institut des Sciences Chimiques de Rennes, CNRS UMR 6226 (France); Blanchard-Desce, Mireille [Universite Bordeaux, Institut des Sciences Moleculaires, UMR CNRS 5255 (France)

    2013-05-15

    An original fluorophore engineered for two-photon excitation or a porphyrin derivative were entrapped in the silica shell of magnetic porous silica nanoparticles during the synthesis of the silica moiety without damaging the structure of the organic part. The mild conditions involved allowed obtaining microporous or mesoporous silica magnetic nanoparticles, respectively. Mannose was grafted on the surface of the nanoparticles to target MCF-7 breast cancer cells. The studies of magnetic properties of these hybrid nanoparticles show that they present a blocking temperature at 190 K. The nano-objects designed with the two-photon fluorophore were efficient for two-photon imaging of MCF-7 cancer cells, whereas the nano-objects with the photosensitizer efficiently killed cancer cells. The presence of the mannose moiety was demonstrated to improve both imaging and therapy properties.

  1. Magnetic Resonance Imaging of Transplanted Neural Stem Cells in Parkinson Disease Rats

    YANG Lin; XIA Ying; ZHAO Hongyang; ZHAO Jiashan; ZHU Xianli

    2006-01-01

    In this study we implanted magnetically labeled neural stem cells (NSCs) in PD rats and then monitored their survival and migration in the host brain by magnetic resonance imaging (MRI).The mesencephalic NSCs were obtained from the brain of SD rats. Superparamagnetic iron oxide (SPIO) was transferred to NSCs by Lipofectamine transfection. Eighteen PD lesioned rats were selected for transplantation by evaluation of their rotational behavior in response to amphetamine and randomly assigned to 3 groups, i.e., sham group, PBS group and NSCs transplanted group, with 6 rats in each group. MR scanning was performed at 1, 2, 4, 6, 8 and 10 week(s) following transplantation.At the meantime, rotational behavior was assessed in each group. Our results showed that SPIO particles were clearly visible with Prissian blue staining in neurospheres and cells derived from NSCs.The rotational behavior of the NSCs transplanted group was remarkably improved compared with that of sham group and PBS group (P<0.05). In vivo MR tracking of NSCs showed that SPIO labeling led to a strong susceptibility change of signal 1 week after transplantation on T2 weighted images.And a large circular hypointense signal appeared in the transplanted area on T2* gradient echo images.Ten weeks following transplantation, the hypointense signal on T2 weighted and T2* gradient echo images was still displayed. It is concluded that SPIO particles could label NSCs effectively, and MRI detection of SPIO labeled cells is a promising method and novel approach to analyzing the NSCs following transplantation in the treatment of PD.

  2. GEM-loaded magnetic albumin nanospheres modified with cetuximab for simultaneous targeting, magnetic resonance imaging, and double-targeted thermochemotherapy of pancreatic cancer cells

    Wang L

    2015-03-01

    Full Text Available Ling Wang,1 Yanli An,2 Chenyan Yuan,3 Hao Zhang,2 Chen Liang,2 Fengan Ding,2 Qi Gao,1 Dongsheng Zhang4 1Department of Ultrasonography, Zhong Da Hospital, Medical School, Southeast University, Nanjing, People’s Republic of China; 2Medical School, Southeast University, Nanjing, People’s Republic of China; 3Department of Clinical Laboratory, Zhong Da Hospital, Medical School, Southeast University, Nanjing, People’s Republic of China; 4Jiangsu Key Laboratory for Biomaterials and Devices, Medical School, Southeast University, Nanjing, People’s Republic of China Background: Targeted delivery is a promising strategy to improve the diagnostic imaging and therapeutic effect of cancers. In this paper, novel cetuximab (C225-conjugated, gemcitabine (GEM-containing magnetic albumin nanospheres (C225-GEM/MANs were fabricated and applied as a theranostic nanocarrier to conduct simultaneous targeting, magnetic resonance imaging (MRI, and double-targeted thermochemotherapy against pancreatic cancer cells. Methods: Fe3O4 nanoparticles (NPs and GEM co-loaded albumin nanospheres (GEM/MANs were prepared, and then C225 was further conjugated to synthesize C225-GEM/MANs. Their morphology, mean particle size, GEM encapsulation ratio, specific cell-binding ability, and thermal dynamic profiles were characterized. The effects of discriminating different EGFR-expressing pancreatic cancer cells (AsPC-1 and MIA PaCa-2 and monitoring cellular targeting effects were assessed by targeted MRI. Lastly, the antitumor efficiency of double/C225/magnetic-targeted and nontargeted thermochemotherapy was compared with chemotherapy alone using 3-(4, 5-dimethyl-2-thiazolyl-2,5-diphenyl-2H-tetrazolium bromide (MTT and flow cytometry (FCM assay. Results: When treated with targeted nanospheres, AsPC-1 cells showed a significantly less intense MRI T2 signal than MIA PaCa-2 cells, while both cells had similar signal strength when incubated with nontargeted nanospheres. T2 signal

  3. Magnetic resonance imaging of prostate cancer cell lines labled with manganese chloride in vitro

    Objective: To assess the feasibility and security of prostate cancer cell lines (PC-3) labeled with manganese chloride (MnCl2) for magnetic resonance imaging (MRI) in vitro. Methods: The PC-3 that purchased from American Type Culture Collection (ATCC) were recovered, cultured and amplified. The PC-3 were cultured in F-12 HAM'S medium with different concentrations of MnCl2 in cell incubator and collected for MRI after 1 hour. The labeled cells were also collected for MRI in different amount and different time after labeling. The labeled cells were incubated with verapamil for 4 hours and the changes of the labeled cellular signal intensities were recorded in different time. Cell Counting Kit-8 (CCK-8) was used to determine the activities of the labeled cells. Results: The PC-3 labeled with MnCl2 were high signal intensities on T1-weighted MRI. There were statistically significant differences between labeled cells and unlabeled cells (P2. The signal intensity obviously decreased after 24 hours and became to normal signal intensity of unlabeled PC-3 after 72 hours. The PC-3 labeled with 1.0 mM MnCl2 solution showed high signal intensity on T1-weighted MRI with the minimum cell amount of 5.0 x 105 and lasted to 72 hours after a 4 hours incubation with verapamil. After 4 hours labeling, except the concentration of 0.1 mM, the other concentrations of MnCl2 (>0.1 mM) had a certain toxicity on PC-3 (P0.05). Conclusion: The PC-3 could be labeled with MnCl2 and appears high signal intensity on T1-weighted MRI. The PC-3 can be safety labeled with MnCl2 in concentrations which were equal or less than 1.0 mM, but the duration of Mn+2 in PC-3 is shorter. Calcium channel blocker (verapamil) may be extend the duration of PC-3 labeled with MnCl2. (authors)

  4. Electric Equivalent Models of Intrinsic Recombination Velocities of a Bifacial Silicon Solar Cell under Frequency Modulation and Magnetic Field Effect

    Nd. Thiam

    2012-11-01

    Full Text Available In this study, we present a theoretical study of the photogenerated charge carriers in the base of an illuminated n+-p-p+ crystalline silicon solar cell under an external magnetic field. By solving the charge carriers’ continuity equation, the dependence of diffusion coefficient and the photocurrent density on the frequency modulation and magnetic field, is studied. Hence, the study of intrinsic recombination velocities at the junction Sfo1 and rear side Sbo1 of the solar cell, leads to electric equivalent models.

  5. Diffusion-weighted magnetic resonance imaging in the differentiation of angiomyolipoma with minimal fat from clear cell renal cell carcinoma

    The aim of the present study was to evaluate diffusion-weighted (DW) magnetic resonance imaging (MRI) in differentiating between minimal fat angiomyolipoma (MFAML) and clear cell renal cell carcinoma (CCRCC). Forty-one solid renal tumors without visible macroscopic fat on unenhanced computed tomography images were evaluated by MRI, including DW-MRI, and were diagnosed pathologically as CCRCC (n=36) or MFAML (n=5). To evaluate the heterogeneity of diffusion in each tumor, the signals of the tumors on DW-MRI were analyzed subjectively and the apparent diffusion coefficient (ADC) values and histograms assessed objectively. Thirty-three of 36 CCRCC (92%) exhibited a heterogeneous signal on DW-MRI and several peaks in the ADC value histogram, whereas four of five MFAML exhibited a homogeneous signal on DW-MRI and a single prominent peak in the histogram. The standard deviations of the ADC values were significantly smaller for MFAML than for CCRCC (P=0.0015). In conclusion, DW-MRI can be considered a useful and noninvasive addition to the preoperative differentiation of CCRCC and MFAML. (author)

  6. Optimized high gradient magnetic separation for isolation of Plasmodium-infected red blood cells

    Chimma Pattamawan

    2010-02-01

    Full Text Available Abstract Background Highly purified infected red blood cells (irbc, or highly synchronized parasite cultures, are regularly required in malaria research. Conventional isolation and synchronization rely on density and osmotic fragility of irbc, respectively. High gradient magnetic separation (HGMS offers an alternative based on intrinsic magnetic properties of irbc, avoiding exposure to chemicals and osmotic stress. Successful HGMS concentration in malaria research was previously reported using polymer coated columns, while HGMS depletion has not been described yet. This study presents a new approach to both HGMS concentration and depletion in malaria research, rendering polymer coating unnecessary. Methods A dipole magnet generating a strong homogenous field was custom assembled. Polypropylene syringes were fitted with one-way stopcocks and filled with stainless steel wool. Rbc from Plasmodium falciparum cultures were resuspended in density and viscosity optimized HGMS buffers and HGMS processed. Purification and depletion results were analysed by flow cytometer and light microscopy. Viability was evaluated by calculating the infection rate after re-culturing of isolates. Results In HGMS concentration, purity of irbc isolates from asynchronous cultures consistently ranged from 94.8% to 98.4% (mean 95.7%. With further optimization, over 90% of isolated irbc contained segmented schizonts. Processing time was less than 45 min. Reinfection rates ranged from 21.0% to 56.4%. In HGMS depletion, results were comparable to treatment with sorbitol, as demonstrated by essentially identical development of cultures. Conclusion The novel HGMS concentration procedure achieves high purities of segmented stage irbc from standard asynchronous cultures, and is the first HGMS depletion alternative to sorbitol lysis. It represents a simple and highly efficient alternative to conventional irbc concentration and synchronization methods.

  7. Transient electrically detected magnetic resonance spectroscopy applied to organic solar cells

    Kraffert, Felix; Steyrleuthner, Robert; Meier, Christoph; Bittl, Robert; Behrends, Jan, E-mail: j.behrends@fu-berlin.de [Berlin Joint EPR Lab, Fachbereich Physik, Freie Universität Berlin, D-14195 Berlin (Germany)

    2015-07-27

    The influence of light-induced paramagnetic states on the photocurrent generated by polymer:fullerene solar cells is studied using spin-sensitive techniques in combination with laser-flash excitation. For this purpose, we developed a setup that allows for simultaneous detection of transient electron paramagnetic resonance as well as transient electrically detected magnetic resonance (trEDMR) signals from fully processed and encapsulated solar cells. Combining both techniques provides a direct link between photoinduced triplet excitons, charge transfer states, and free charge carriers as well as their influence on the photocurrent generated by organic photovoltaic devices. Our results obtained from solar cells based on poly(3-hexylthiophene) as electron donor and a fullerene-based electron acceptor show that the resonant signals observed in low-temperature (T = 80 K) trEDMR spectra can be attributed to positive polarons in the polymer as well as negative polarons in the fullerene phase, indicating that both centers are involved in spin-dependent processes that directly influence the photocurrent.

  8. Estimation of cell membrane permeability of the rat brain using diffusion magnetic resonance imaging

    Imae, T.; Shinohara, H.; Sekino, M.; Ueno, S.; Ohsaki, H.; Mima, K.; Ootomo, K.

    2008-04-01

    We propose a method to noninvasively evaluate the permeability of the cell membrane in the rat brain using diffusion magnetic resonance imaging (MRI). Diffusion MRI reflects the intra- and extracellular diffusion coefficients of water and cell membrane permeability. The images were acquired using a 4.7T MRI system with applications to motion-probing gradients in six directions. Numerical simulations based on the finite-difference method were carried out for estimating diffusion MRI signals with various combinations of membrane permeability and intracellular diffusion coefficient values. We defined an evaluative function as the difference between the signals estimated by simulation and experimentally obtained signals. We found that the combination of membrane permeability and intracellular diffusion coefficient in the simulation corresponding to the minimum value of the evaluative function leads to an estimation of these properties of the rat brain. The estimated intracellular diffusion coefficient and membrane permeability were (1.3±0.1)×10-3mm2/s and 74±23μm/s, respectively. Our method is useful for noninvasively estimating the cell membrane permeability of biological tissues, and is easily applicable to human tissues.

  9. Sensitive and Direct Detection of Circulating Tumor Cells by Multimarker µ-Nuclear Magnetic Resonance

    Arezou A. Ghazani

    2012-05-01

    Full Text Available Identifying circulating tumor cells (CTCs with greater sensitivity could facilitate early detection of cancer and rapid assessment of treatment response. Most current technologies use EpCAM expression as a CTC identifier. However, given that a significant fraction of cancer patients have low or even absent EpCAM levels, there is a need for better detection methods. Here, we hypothesize that a multimarker strategy combined with direct sensing of CTC in whole blood would increase the detection of CTC in patients. Accordingly, molecular profiling of biopsies from a patient cohort revealed a four-marker set (EpCAM, HER-2, EGFR, and MUC-1 capable of effectively differentiating cancer cells from normal host cells. Using a point-of-care micro-nuclear magnetic resonance (µNMR system, we consequently show that this multimarker combination readily detects individual CTC directly in whole blood without the need for primary purification. We also confirm these results in a comparative trial of patients with ovarian cancer. This platform could potentially benefit a broad range of applications in clinical oncology.

  10. Transient electrically detected magnetic resonance spectroscopy applied to organic solar cells

    The influence of light-induced paramagnetic states on the photocurrent generated by polymer:fullerene solar cells is studied using spin-sensitive techniques in combination with laser-flash excitation. For this purpose, we developed a setup that allows for simultaneous detection of transient electron paramagnetic resonance as well as transient electrically detected magnetic resonance (trEDMR) signals from fully processed and encapsulated solar cells. Combining both techniques provides a direct link between photoinduced triplet excitons, charge transfer states, and free charge carriers as well as their influence on the photocurrent generated by organic photovoltaic devices. Our results obtained from solar cells based on poly(3-hexylthiophene) as electron donor and a fullerene-based electron acceptor show that the resonant signals observed in low-temperature (T = 80 K) trEDMR spectra can be attributed to positive polarons in the polymer as well as negative polarons in the fullerene phase, indicating that both centers are involved in spin-dependent processes that directly influence the photocurrent

  11. Measurements of magnetic relaxation times of normal tissue and renal cell carcinoma

    Spin-lattice (T1) and spin-spin (T2) magnetic relaxation times of 25 human renal cell carcinomas and their assorted normal tissues were measured with a Bruker NMR spectrometer operating at 20 MHz. The tissue samples were examined within four hours after surgery. The results (mean±SD) were as follows: renal cell carcinoma, T1=638±168 msec and T2=109±41 msec; normal renal tissue, T1=594±165 msec and T2=100±24 msec. These results indicate that there was no significant difference in T1 and T2 between normal renal tissue and carcinoma. Our results suggest that it is difficult to separate relaxation times of renal cancer from those of normal parenchyma and that the difference between T1 and T2 alone dose not permit recognition of renal cell cancer. Paramagnetic contrast agents may be useful in MR imaging to differentiate renal cancer from normal parenchyma. (author)

  12. Anvil cell gasket design for high pressure nuclear magnetic resonance experiments beyond 30 GPa

    Nuclear magnetic resonance (NMR) experiments are reported at up to 30.5 GPa of pressure using radiofrequency (RF) micro-coils with anvil cell designs. These are the highest pressures ever reported with NMR, and are made possible through an improved gasket design based on nano-crystalline powders embedded in epoxy resin. Cubic boron-nitride (c-BN), corundum (α-Al2O3), or diamond based composites have been tested, also in NMR experiments. These composite gaskets lose about 1/2 of their initial height up to 30.5 GPa, allowing for larger sample quantities and preventing damages to the RF micro-coils compared to precipitation hardened CuBe gaskets. It is shown that NMR shift and resolution are less affected by the composite gaskets as compared to the more magnetic CuBe. The sensitivity can be as high as at normal pressure. The new, inexpensive, and simple to engineer gaskets are thus superior for NMR experiments at high pressures

  13. Anvil cell gasket design for high pressure nuclear magnetic resonance experiments beyond 30 GPa

    Meier, Thomas; Haase, Jürgen

    2015-12-01

    Nuclear magnetic resonance (NMR) experiments are reported at up to 30.5 GPa of pressure using radiofrequency (RF) micro-coils with anvil cell designs. These are the highest pressures ever reported with NMR, and are made possible through an improved gasket design based on nano-crystalline powders embedded in epoxy resin. Cubic boron-nitride (c-BN), corundum (α-Al2O3), or diamond based composites have been tested, also in NMR experiments. These composite gaskets lose about 1/2 of their initial height up to 30.5 GPa, allowing for larger sample quantities and preventing damages to the RF micro-coils compared to precipitation hardened CuBe gaskets. It is shown that NMR shift and resolution are less affected by the composite gaskets as compared to the more magnetic CuBe. The sensitivity can be as high as at normal pressure. The new, inexpensive, and simple to engineer gaskets are thus superior for NMR experiments at high pressures.

  14. Anvil cell gasket design for high pressure nuclear magnetic resonance experiments beyond 30 GPa

    Meier, Thomas; Haase, Jürgen [Faculty of Physics and Earth Sciences, University of Leipzig, Linnéstrasse 5, Leipzig 04103 (Germany)

    2015-12-15

    Nuclear magnetic resonance (NMR) experiments are reported at up to 30.5 GPa of pressure using radiofrequency (RF) micro-coils with anvil cell designs. These are the highest pressures ever reported with NMR, and are made possible through an improved gasket design based on nano-crystalline powders embedded in epoxy resin. Cubic boron-nitride (c-BN), corundum (α-Al{sub 2}O{sub 3}), or diamond based composites have been tested, also in NMR experiments. These composite gaskets lose about 1/2 of their initial height up to 30.5 GPa, allowing for larger sample quantities and preventing damages to the RF micro-coils compared to precipitation hardened CuBe gaskets. It is shown that NMR shift and resolution are less affected by the composite gaskets as compared to the more magnetic CuBe. The sensitivity can be as high as at normal pressure. The new, inexpensive, and simple to engineer gaskets are thus superior for NMR experiments at high pressures.

  15. Lactoferrin conjugated iron oxide nanoparticles for targeting brain glioma cells in magnetic particle imaging

    Tomitaka, Asahi; Arami, Hamed; Gandhi, Sonu; Krishnan, Kannan M.

    2015-10-01

    Magnetic Particle Imaging (MPI) is a new real-time imaging modality, which promises high tracer mass sensitivity and spatial resolution directly generated from iron oxide nanoparticles. In this study, monodisperse iron oxide nanoparticles with median core diameters ranging from 14 to 26 nm were synthesized and their surface was conjugated with lactoferrin to convert them into brain glioma targeting agents. The conjugation was confirmed with the increase of the hydrodynamic diameters, change of zeta potential, and Bradford assay. Magnetic particle spectrometry (MPS), performed to evaluate the MPI performance of these nanoparticles, showed no change in signal after lactoferrin conjugation to nanoparticles for all core diameters, suggesting that the MPI signal is dominated by Néel relaxation and thus independent of hydrodynamic size difference or presence of coating molecules before and after conjugations. For this range of core sizes (14-26 nm), both MPS signal intensity and spatial resolution improved with increasing core diameter of nanoparticles. The lactoferrin conjugated iron oxide nanoparticles (Lf-IONPs) showed specific cellular internalization into C6 cells with a 5-fold increase in MPS signal compared to IONPs without lactoferrin, both after 24 h incubation. These results suggest that Lf-IONPs can be used as tracers for targeted brain glioma imaging using MPI.

  16. Particle-in-Cell Modeling of Magnetized Argon Plasma Flow Through Small Mechanical Apertures

    Adam B. Sefkow and Samuel A. Cohen

    2009-04-09

    Motivated by observations of supersonic argon-ion flow generated by linear helicon-heated plasma devices, a three-dimensional particle-in-cell (PIC) code is used to study whether stationary electrostatic layers form near mechanical apertures intersecting the flow of magnetized plasma. By self-consistently evaluating the temporal evolution of the plasma in the vicinity of the aperture, the PIC simulations characterize the roles of the imposed aperture and applied magnetic field on ion acceleration. The PIC model includes ionization of a background neutral-argon population by thermal and superthermal electrons, the latter found upstream of the aperture. Near the aperture, a transition from a collisional to a collisionless regime occurs. Perturbations of density and potential, with mm wavelengths and consistent with ion acoustic waves, propagate axially. An ion acceleration region of length ~ 200-300 λD,e forms at the location of the aperture and is found to be an electrostatic double layer, with axially-separated regions of net positive and negative charge. Reducing the aperture diameter or increasing its length increases the double layer strength.

  17. CpG oligodeoxynucleotide-loaded PAMAM dendrimer-coated magnetic nanoparticles promote apoptosis in breast cancer cells.

    Taghavi Pourianazar, Negar; Gunduz, Ufuk

    2016-03-01

    One major application of nanotechnology in cancer treatment involves designing nanoparticles to deliver drugs, oligonucleotides, and genes to cancer cells. Nanoparticles should be engineered so that they could target and destroy tumor cells with minimal damage to healthy tissues. This research aims to develop an appropriate and efficient nanocarrier, having the ability of interacting with and delivering CpG-oligodeoxynucleotides (CpG-ODNs) to tumor cells. CpG-ODNs activate Toll-like receptor 9 (TLR9), which can generate a signal cascade for cell death. In our study, we utilized three-layer magnetic nanoparticles composed of a Fe3O4 magnetic core, an aminosilane (APTS) interlayer and a cationic poly(amidoamine) (PAMAM) dendrimer. This will be a novel targeted delivery system to enhance the accumulation of CpG-ODN molecules in tumor cells. The validation of CpG-ODN binding to DcMNPs was performed using agarose gel electrophoresis, UV-spectrophotometer, XPS analyses. Cytotoxicity of conjugates was assessed in MDA-MB231 and SKBR3 cancer cells based on cell viability by XTT assay and flow cytometric analysis. Our results indicated that the synthesized DcMNPs having high positive charges on their surface could attach to CpG-ODN molecules via electrostatic means. These nanoparticles with the average sizes of 40±10nm bind to CpG-ODN molecules efficiently and induce cell death in MDA-MB231 and SKBR3 tumor cells and could be considered a suitable targeted delivery system for CpG-ODN in biomedical applications. The magnetic core of these nanoparticles represents a promising option for selective drug targeting as they can be concentrated and held in position by means of an external magnetic field. PMID:26898428

  18. Application of pulsed-magnetic field enhances non-viral gene delivery in primary cells from different origins

    Kamau Chapman, Sarah W. [Institute of Veterinary Biochemistry and Molecular Biology, University of Zurich, Winterthurerstr. 190, 8057 Zurich (Switzerland); Hassa, Paul O. [Institute of Veterinary Biochemistry and Molecular Biology, University of Zurich, Winterthurerstr. 190, 8057 Zurich (Switzerland); European Molecular Biology Laboratory (EMBL) Heidelberg, Meyerhofstrasse 1, 69117 Heidelberg (Germany); Koch-Schneidemann, Sabine; Rechenberg, Brigitte von [Musculoskeletal Research Unit, Equine Hospital, Vetsuisse Faculty Zurich, University of Zurich, Winterthurerstr. 260, 8057 Zurich (Switzerland); Hofmann-Amtenbrink, Margarethe [MatSearch, Chemin Jean Pavillard 14, 1009 Pully (Switzerland); Steitz, Benedikt; Petri-Fink, Alke; Hofmann, Heinrich [Laboratory of Powder Technology, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne (Switzerland); Hottiger, Michael O. [Institute of Veterinary Biochemistry and Molecular Biology, University of Zurich, Winterthurerstr. 190, 8057 Zurich (Switzerland)], E-mail: hottiger@vetbio.uzh.ch

    2008-04-15

    Primary cell lines are more difficult to transfect when compared to immortalized/transformed cell lines, and hence new techniques are required to enhance the transfection efficiency in these cells. We isolated and established primary cultures of synoviocytes, chondrocytes, osteoblasts, melanocytes, macrophages, lung fibroblasts, and embryonic fibroblasts. These cells differed in several properties, and hence were a good representative sample of cells that would be targeted for expression and delivery of therapeutic genes in vivo. The efficiency of gene delivery in all these cells was enhanced using polyethylenimine-coated polyMAG magnetic nanoparticles, and the rates (17-84.2%) surpassed those previously achieved using other methods, especially in cells that are difficult to transfect. The application of permanent and pulsating magnetic fields significantly enhanced the transfection efficiencies in synoviocytes, chondrocytes, osteoblasts, melanocytes and lung fibroblasts, within 5 min of exposure to these magnetic fields. This is an added advantage for future in vivo applications, where rapid gene delivery is required before systemic clearance or filtration of the gene vectors occurs.

  19. A dual mode targeting probe for distinguishing HER2-positive breast cancer cells using silica-coated fluorescent magnetic nanoparticles

    Li, Jia [Medical School Southeast University, Department of Ultrasonography, Zhongda Hospital (China); An, Yan-Li; Zang, Feng-Chao [Southeast University, Jiangsu Key Laboratory of Molecular and Functional Imaging (China); Zong, Shen-Fei; Cui, Yi-Ping, E-mail: cyp@seu.edu.cn [Southeast University, Advanced Photonics Center (China); Teng, Gao-Jun, E-mail: gjteng@vip.sina.com [Southeast University, Jiangsu Key Laboratory of Molecular and Functional Imaging (China)

    2013-10-15

    We report a composite nanoprobe based on silica-coated magnetic nanoparticles (NPs) for distinguishing breast cancers at different HER2 statuses. The nanoprobe has a core-shell structure, with Fe{sub 3}O{sub 4} NPs as the magnetic core and dye-embedded silica as the fluorescent shell, whose average size is about 150 nm. Besides, the outmost surfaces of the probes were modified with specific antibodies to endow the probe with a targeting ability. With such a structure, the nanoprobe can accomplish dual mode targeting of human breast cancer cells based on fluorescence and magnetic resonance imaging (MRI). In the experiments, three human breast cancer cell lines were used to test the targeting ability of the nanoprobe. Specifically, SKBR3 cells with a high HER2 expression level were used as the model target cells, while MCF7 cells with a lower HER2 expression levels and HER2-negative MDA-MB-231 cells were used as the controls. Both the fluorescence and MRI imaging results confirmed that the nanoprobe can distinguish three cancer cell lines with different HER2 expression levels. With the dual mode imaging and specific targeting properties, we anticipate that the presented nanoprobe may have a great potential in the diagnosis and treatment of cancerous diseases.

  20. Application of pulsed-magnetic field enhances non-viral gene delivery in primary cells from different origins

    Primary cell lines are more difficult to transfect when compared to immortalized/transformed cell lines, and hence new techniques are required to enhance the transfection efficiency in these cells. We isolated and established primary cultures of synoviocytes, chondrocytes, osteoblasts, melanocytes, macrophages, lung fibroblasts, and embryonic fibroblasts. These cells differed in several properties, and hence were a good representative sample of cells that would be targeted for expression and delivery of therapeutic genes in vivo. The efficiency of gene delivery in all these cells was enhanced using polyethylenimine-coated polyMAG magnetic nanoparticles, and the rates (17-84.2%) surpassed those previously achieved using other methods, especially in cells that are difficult to transfect. The application of permanent and pulsating magnetic fields significantly enhanced the transfection efficiencies in synoviocytes, chondrocytes, osteoblasts, melanocytes and lung fibroblasts, within 5 min of exposure to these magnetic fields. This is an added advantage for future in vivo applications, where rapid gene delivery is required before systemic clearance or filtration of the gene vectors occurs

  1. Application of pulsed-magnetic field enhances non-viral gene delivery in primary cells from different origins

    Kamau Chapman, Sarah W.; Hassa, Paul O.; Koch-Schneidemann, Sabine; von Rechenberg, Brigitte; Hofmann-Amtenbrink, Margarethe; Steitz, Benedikt; Petri-Fink, Alke; Hofmann, Heinrich; Hottiger, Michael O.

    Primary cell lines are more difficult to transfect when compared to immortalized/transformed cell lines, and hence new techniques are required to enhance the transfection efficiency in these cells. We isolated and established primary cultures of synoviocytes, chondrocytes, osteoblasts, melanocytes, macrophages, lung fibroblasts, and embryonic fibroblasts. These cells differed in several properties, and hence were a good representative sample of cells that would be targeted for expression and delivery of therapeutic genes in vivo. The efficiency of gene delivery in all these cells was enhanced using polyethylenimine-coated polyMAG magnetic nanoparticles, and the rates (17-84.2%) surpassed those previously achieved using other methods, especially in cells that are difficult to transfect. The application of permanent and pulsating magnetic fields significantly enhanced the transfection efficiencies in synoviocytes, chondrocytes, osteoblasts, melanocytes and lung fibroblasts, within 5 min of exposure to these magnetic fields. This is an added advantage for future in vivo applications, where rapid gene delivery is required before systemic clearance or filtration of the gene vectors occurs.

  2. Application of a weak magnetic field to improve microbial fuel cell performance.

    Tong, Zhong-Hua; Yu, Han-Qing; Li, Wen-Wei; Wang, Yun-Kun; Sun, Min; Liu, Xian-Wei; Sheng, Guo-Ping

    2015-12-01

    Microbial fuel cells (MFCs) have emerged as a promising technology for wastewater treatment with concomitant energy production but the performance is usually limited by low microbial activities. This has spurred intensive research interest for microbial enhancement. This study demonstrated an interesting stimulation effect of a static magnetic field (MF) on sludge-inoculated MFCs and explored into the mechanisms. The implementation of a 100-mT MF accelerated the reactor startup and led to increased electricity generation. Under the MF exposure, the activation loss of the MFC was decreased, but there was no increased secretion of redox mediators. Thus, the MF effect was mainly due to enhanced bioelectrochemical activities of anodic microorganisms, which are likely attributed to the oxidative stress and magnetohydrodynamic effects under an MF exposure. This work implies that weak MF may be applied as a simple and effective approach to stimulate microbial activities for various bioelectrochemical energy production and decontamination applications. PMID:26410373

  3. Estimation of genetic effects of static magnetic fields (SMFs) on the pollen mother cells (PMCs) of wheats

    The effect of static magnetic fields (SMFs) on the chromosome aberrations in the pollen mother cells (PMCs) of wheat was studied. The seeds of wheat were exposed to static magnetic fields of different magnetic flux density (0, 1, 3, 5 and 7 Tesla) for 5h and with different treated time (1, 3 and 5h) at magnetic flux density of 7 Tesla. The genotoxic effect was evaluated in terms of micronucleus (MN), chromosomal bridge, lagging chromosome, abnormal segregation and fragment in PMCs. The results indicated that the exposed groups of low field intensity (below 5 Tesla) showed no statistically significant difference in aberration frequency compared with unexposed control groups and sham exposed groups, but significant differences of chromosomal bridge at 5T and lagging chromosome, triple-polar segregation or micronucleus at 7T were detected in the exposed group (p<0.05). The dose-effect relationships indicated that the increase frequency of meiotic abnormal cells correlated with flux density of magnetic field and treated time, but no linear effect was observed. These results lead us to the conclusion that high static magnetic fields above 5T for 5h duration might cause an increase in potential damage to organisms. (authors)

  4. Transplantation of magnetically labeled mesenchymal stem cells improves cardiac function in a swine myocardial infarction model

    QI Chun-mei; JU Sheng-hong; MA Ming; TANG Yao-liang; MA Gen-shan; LIU Nai-feng; SHEN Cheng-xing; CHEN Zhong; LIU Xiao-jun; HU Yao-peng; ZHANG Xiao-li; TENG Gao-jun

    2008-01-01

    Background Mesenchymal stem cells (MSCs) transplantation provides a new approach for myocardial repair.However,many important fundamental questions about MSCs transplantation remain unanswered.There is an urgent need to identify MSCs from the beating heart and analyze the efficacy of this new approach.This study aimed to localize the magnetically labeled MSCs(MR-MSCs)and monitor the restorative effects of MR-MSCs with magnetic resonance(MR) imaging.Methods Acute myocardial infarction(AMI)was created in swine by a balloon occlusion of the left anterior descending coronary artery.Cells were delivered via intracoronary infusion after myocardial infarction.Infarct size change and cardiac function were assessed with 3.0T MR scanner.The results were then confirmed by histological and western blot analysis.All statistical procedures were performed with Systat (SPSS version 12.01).Results A total of 26 swine were divided into four groups(sham-operated group,n=6;AMI group with PBS transplantation,n=6;labeled MSCs group,n=7;unlabeled MSCs group,n=7).MSCs,MR-MSCs(107 cells)or PBS were delivered by intracoronary injection after MI and serial cardiac MR imaging studies were performed at 0,4 and 8 weeks after transplantation.MR imaging demonstrated MI size decreased after MSCs transplantation in labeled and unlabeled groups,however,increases were seen in the AMI group at 8 weeks after MI.The left ventricular eiection fraction(LVEF) was slightly increased in the AMI group((41.87±2.45)%vs(39.04±2.80)%,P>0.05),but significantly improved in the MR-MSCs group((56.85±1.29)%vs(40.67±2.00)%,P<0.05)and unlabeled group((55.38±1.07)%vs(41.78±2.08)%,P<0.05) at 8 weeks after treatment.MR-MSCs were further confirmed by Prussian blue and immunofluorescent staining.Western blot analvsis demonstrated that there was an increased expression of cardiomyocyte markers such as myosin heavy chain and troponin T in the MSCs treatment groups and the ratio of matrix metalloproteinase 2 to

  5. Electrostatically Stabilized Magnetic Nanoparticles – An Optimized Protocol to Label Murine T Cells for in vivo MRI

    Wuerfel, Eva; Smyth, Maureen; Millward, Jason M.; Schellenberger, Eyk; Glumm, Jana; Prozorovski, Timour; Aktas, Orhan; Schulze-Topphoff, Ulf; Schnorr, Jörg; Wagner, Susanne; Taupitz, Matthias; Infante-Duarte, Carmen; Wuerfel, Jens

    2011-01-01

    We present a novel highly efficient protocol to magnetically label T cells applying electrostatically stabilized very small superparamagnetic iron oxide particles (VSOP). Our long-term aim is to use magnetic resonance imaging (MRI) to investigate T cell dynamics in vivo during the course of neuroinflammatory disorders such as experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Encephalitogenic T cells were co-incubated with VSOP, or with protamine-complexed VSOP (VProt), respectively, at different conditions, optimizing concentrations and incubation times. Labeling efficacy was determined by atomic absorption spectrometry as well as histologically, and evaluated on a 7 T MR system. Furthermore, we investigated possible alterations of T cell physiology caused by the labeling procedure. T cell co-incubation with VSOP resulted in an efficient cellular iron uptake. T2 times of labeled cells dropped significantly, resulting in prominent hypointensity on T2*-weighted scans. Optimal labeling efficacy was achieved by VProt (1 mM Fe/ml, 8 h incubation; T2 time shortening of ∼80% compared to untreated cells). Although VSOP promoted T cell proliferation and altered the ratio of T cell subpopulations toward a CD4+ phenotype, no effects on CD4 T cell proliferation or phenotypic stability were observed by labeling in vitro differentiated Th17 cells with VProt. Yet, high concentrations of intracellular iron oxide might induce alterations in T cell function, which should be considered in cell tagging studies. Moreover, we demonstrated that labeling of encephalitogenic T cells did not affect pathogenicity; labeled T cells were still capable of inducing EAE in susceptible recipient mice. PMID:22203815

  6. Isolation of prostate cancer cell subpopulations of functional interest by use of an on-chip magnetic bead-based cell separator

    This work presents the design, fabrication and characterization of a modular magnetic bead-based cell separation device developed for the sequential sorting of a heterogeneous prostate cancer (CaP) cell population. The chief aim is cell sorting carried out on the basis of surface marker expression, serially selecting cellular subpopulations for capture by the use of antibody-coated magnetic beads. The markers of interest, prostate specific membrane antigen (PSMA) and CD10 were selected for their relevance to ongoing CaP development research. The separation device was fabricated out of plastic, by the use of cyclic olefin copolymer (COC) injection molding, nickel–iron electroplating and thermoplastic fusion bonding. Effective depletion and enrichment of cell subsets based on multiple surface markers was achieved. Various flow rates and incubation times were tested for optimizing the sorting procedure

  7. The promotion of in vitro vessel-like organization of endothelial cells in magnetically responsive alginate scaffolds

    Sapir, Yulia; Cohen, Smadar; Friedman, Gary; Polyak, Boris

    2012-01-01

    One of the major challenges in engineering thick, complex tissues such as cardiac muscle, is the need to pre-vascularize the engineered tissue in vitro to enable its efficient integration with host tissue upon implantation. Herein, we explored new magnetic alginate composite scaffolds to provide means of physical stimulation to cells. Magnetite-impregnated alginate scaffolds seeded with aortic endothelial cells stimulated during the first 7 days out of a total 14 day experimental course showe...

  8. Phosphorus-31 and carbon-13 nuclear magnetic resonance studies of glucose and xylose metabolism in Candida tropicalis cell suspensions.

    Lohmeier-Vogel, E M; Hahn-Hägerdal, B.; Vogel, H J

    1995-01-01

    The metabolism of glucose and xylose was studied as a function of oxygenation in suspensions of Candida tropicalis by 31P and 13C nuclear magnetic resonance spectroscopy. Both the rate of carbohydrate metabolism and the cytoplasmic pH were independent of the rate of oxygenation in cells metabolizing glucose. However, these two parameters were markedly dependent on the rate of oxygenation in C. tropicalis cells metabolizing xylose. For example, the cytoplasmic pH in fully oxygenated xylose-met...

  9. Self-organization model for a cell system: Ferroelectric, ferroelastic, and magnetic states and related phase transitions

    A model is proposed to explain the stability, phase state transformations, and coexistence of different phases for fungi cell ensembles (in particular, dimorphism and linear-to-spiral structure transitions with the Earth's magnetic field screened). This model is based on (i) cell-connected soft polarization modes induced by charge compensation and related ferroelectric and ferroelastic phase transitions and (ii) intracell mobile orbit-spin-lattice clusters with competitive ferromagnetic-diamagnetic behavior and with orbitlattice and spin-lattice interactions. This model makes it possible to explain the structural and magnetic properties of the systems under consideration. In particular, the Lifshitz invariants in the free energy explain the formation of orbit-lattice and spin-lattice spiral and ring-type structures that are formed when the Earth's magnetic field is effectively screened. The model proposed is not restricted to mitochondria, containing orbit-spin-lattice clusters based on the Fe3+/Fe2+ states (considered here).

  10. The effect of novel magnetic nanoparticles on vascular endothelial cell function in vitro and in vivo

    Su, Le; Han, Lei [Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Science, Shandong University, Jinan 250100 (China); Ge, Fei [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Zhang, Shang Li [Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Science, Shandong University, Jinan 250100 (China); Zhang, Yun [The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, Shandong University Qilu Hospital, Jinan 250100 (China); Zhao, Bao Xiang, E-mail: bxzhao@sdu.edu.cn [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Zhao, Jing [Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Science, Shandong University, Jinan 250100 (China); Miao, Jun Ying, E-mail: miaojy@sdu.edu.cn [Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Science, Shandong University, Jinan 250100 (China); The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, Shandong University Qilu Hospital, Jinan 250100 (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer The novel nanoparticles could internalize in HUVEC and diffuse in the cytoplasm. Black-Right-Pointing-Pointer 1-200 {mu}g/ml MNPs did not affect HUVECs and could be safe to HUVECs in vitro. Black-Right-Pointing-Pointer 400 {mu}g/ml MNPs inhibited cell growth regulated by caveolin-1 and eNOS. Black-Right-Pointing-Pointer 20 mg/kg MNPs damaged endothelium in the aortic root after injected for 3 days. Black-Right-Pointing-Pointer After injected for 6 days and 9 days, the endothelium recovered the integrity. - Abstract: Manufactured nanoparticles are currently used for many fields. However, their potential toxicity provides a growing concern for human health. In our previous study, we prepared novel magnetic nanoparticles (MNPs), which could effectively remove heavy metal ions and cationic dyes from aqueous solution. To understand its biocompatibility, we investigated the effect of the nanoparticles on the function of vascular endothelial cells. The results showed that the nanoparticles were taken up by human umbilical vein endothelial cells (HUVECs) and could inhibit cell proliferation at 400 {mu}g/ml. An increase in nitric oxide (NO) production and endothelial nitric oxide synthase (eNOS) activity were induced, which companied with the decrease in caveolin-1 level. The endothelium in the aortic root was damaged and the NO level in serum was elevated after treated mice with 20 mg/kg nanoparticles for 3 days, but it was integrated after treated with 5 mg/kg nanoparticles. Meanwhile, an increase in eNOS activity and decrease in caveolin-1 level were induced in the endothelium. The data suggested that the low concentration of nanoparticles could not affect the function and viability of VECs. The high concentration of nanoparticles could inhibit VEC proliferation through elevation of the eNOS activity and NO production and thus present toxicity.

  11. Biocompatibility of magnetic Fe3O4 nanoparticles and their cytotoxic effect on MCF-7 cells

    Chen DZ

    2012-09-01

    Full Text Available Daozhen Chen,1,3,* Qiusha Tang,2,* Xiangdong Li,3,* Xiaojin Zhou,1 Jia Zang,1 Wen-qun Xue,1 Jing-ying Xiang,1 Cai-qin Guo11Central Laboratory, Wuxi Hospital for Matemaland Child Health Care Affiliated Medical School of Nanjing, Jiangsu Province; 2Department of Pathology and Pathophysiology, Medical College, Southeast University, Jiangsu Province; 3The People’s Hospital of Aheqi County, Xinjiang, China *These authors contributed equally to this workBackground: The objective of this study was to evaluate the synthesis and biocompatibility of Fe3O4 nanoparticles and investigate their therapeutic effects when combined with magnetic fluid hyperthermia on cultured MCF-7 cancer cells.Methods: Magnetic Fe3O4 nanoparticles were prepared using a coprecipitation method. The appearance, structure, phase composition, functional groups, surface charge, magnetic susceptibility, and release in vitro were characterized by transmission electron microscopy, x-ray diffraction, scanning electron microscopy-energy dispersive x-ray spectroscopy, and a vibrating sample magnetometer. Blood toxicity, in vitro toxicity, and genotoxicity were investigated. Therapeutic effects were evaluated by MTT [3-(4, 5-dimethyl-2-thiazolyl-2, 5-diphenyl-2H-tetrazolium bromide] and flow cytometry assays.Results: Transmission electron microscopy revealed that the shapes of the Fe3O4 nanoparticles were approximately spherical, with diameters of about 26.1 ± 5.2 nm. Only the spinel phase was indicated in a comparison of the x-ray diffraction data with Joint Corporation of Powder Diffraction Standards (JCPDS X-ray powder diffraction files. The O-to-Fe ratio of the Fe3O4 was determined by scanning electron microscopy-energy dispersive x-ray spectroscopy elemental analysis, and approximated pure Fe3O4. The vibrating sample magnetometer hysteresis loop suggested that the Fe3O4 nanoparticles were superparamagnetic at room temperature. MTT experiments showed that the toxicity of the material

  12. In vivo MR imaging of nanometer magnetically labeled bone marrow stromal cells transplanted via portal vein in rat liver

    Objective: To evaluate in vivo magnetic resonance imaging with a conventional 1.5-T system for tracking of intra-portal vein transplantation nanometer magnetically labeled BMSCs in rat liver. Methods: BMSCs were isolated from 5 SD rats bone marrow with the density gradient centrifugation method. Then BMSCs were labeled with nanometer superpara-magnetic iron oxide and transfection agent. Cell labeling efficiency was assessed with determination of the percentage of Peris Prussian blue stain. Then BMSCs transplanted into normal rats' livers via portal vein. The receipts were divided into 5 groups ,including sham control,2 h ,3 d,7 d and 2 w after transplantation. Follow-up serial T1WI,T2WI and T2*-weighted gradient- echo MR imaging were performed at 1.5 T MRI system. MR imaging findings were compared with histology. Results: Cell labeling efficiency was more than 95% by Perls Prussian blue stain. After transplantation of labeled BMSCs via portal vein, liver's had diffuse granular signal intensity appearance in T2* WI MRI. Cells were detected for up to 2 w in receipts' liver's. At histologic analysis, signal intensity loss correlated with iron-loaded cells. Conclusion: MR imaging could aid in monitoring of magnetically labeled BMSCs administered via portal vein in vivo. (authors)

  13. Characterization of proton exchange membrane materials for fuel cells by solid state nuclear magnetic resonance

    Kong, Zueqian [Iowa State Univ., Ames, IA (United States)

    2010-01-01

    Solid-state nuclear magnetic resonance (NMR) has been used to explore the nanometer-scale structure of Nafion, the widely used fuel cell membrane, and its composites. We have shown that solid-state NMR can characterize chemical structure and composition, domain size and morphology, internuclear distances, molecular dynamics, etc. The newly-developed water channel model of Nafion has been confirmed, and important characteristic length-scales established. Nafion-based organic and inorganic composites with special properties have also been characterized and their structures elucidated. The morphology of Nafion varies with hydration level, and is reflected in the changes in surface-to-volume (S/V) ratio of the polymer obtained by small-angle X-ray scattering (SAXS). The S/V ratios of different Nafion models have been evaluated numerically. It has been found that only the water channel model gives the measured S/V ratios in the normal hydration range of a working fuel cell, while dispersed water molecules and polymer ribbons account for the structures at low and high hydration levels, respectively.

  14. BIGEL analysis of gene expression in HL60 cells exposed to X rays or 60 Hz magnetic fields

    Balcer-Kubiczek, E. K.; Zhang, X. F.; Han, L. H.; Harrison, G. H.; Davis, C. C.; Zhou, X. J.; Ioffe, V.; McCready, W. A.; Abraham, J. M.; Meltzer, S. J.

    1998-01-01

    We screened a panel of 1,920 randomly selected cDNAs to discover genes that are differentially expressed in HL60 cells exposed to 60 Hz magnetic fields (2 mT) or X rays (5 Gy) compared to unexposed cells. Identification of these clones was accomplished using our two-gel cDNA library screening method (BIGEL). Eighteen cDNAs differentially expressed in X-irradiated compared to control HL60 cells were recovered from a panel of 1,920 clones. Differential expression in experimental compared to control cells was confirmed independently by Northern blotting of paired total RNA samples hybridized to each of the 18 clone-specific cDNA probes. DNA sequencing revealed that 15 of the 18 cDNA clones produced matches with the database for genes related to cell growth, protein synthesis, energy metabolism, oxidative stress or apoptosis (including MYC, neuroleukin, copper zinc-dependent superoxide dismutase, TC4 RAS-like protein, peptide elongation factor 1alpha, BNIP3, GATA3, NF45, cytochrome c oxidase II and triosephosphate isomerase mRNAs). In contrast, BIGEL analysis of the same 1,920 cDNAs revealed no differences greater than 1.5-fold in expression levels in magnetic-field compared to sham-exposed cells. Magnetic-field-exposed and control samples were analyzed further for the presence of mRNA encoding X-ray-responsive genes by hybridization of the 18 specific cDNA probes to RNA from exposed and control HL60 cells. Our results suggest that differential gene expression is induced in approximately 1% of a random pool of cDNAs by ionizing radiation but not by 60 Hz magnetic fields under the present experimental conditions.

  15. Improved Mitochondrial and Methylglyoxal-Related Metabolisms Support Hyperproliferation Induced by 50 Hz Magnetic Field in Neuroblastoma Cells.

    Falone, Stefano; Santini, Silvano; di Loreto, Silvia; Cordone, Valeria; Grannonico, Marta; Cesare, Patrizia; Cacchio, Marisa; Amicarelli, Fernanda

    2016-09-01

    Extremely low frequency magnetic fields (ELF-MF) are common environmental agents that are suspected to promote later stages of tumorigenesis, especially in brain-derived malignancies. Even though ELF magnetic fields have been previously linked to increased proliferation in neuroblastoma cells, no previous work has studied whether ELF-MF exposure may change key biomolecular features, such as anti-glycative defence and energy re-programming, both of which are currently considered as crucial factors involved in the phenotype and progression of many malignancies. Our study investigated whether the hyperproliferation that is induced in SH-SY5Y human neuroblastoma cells by a 50 Hz, 1 mT ELF magnetic field is supported by an improved defense towards methylglyoxal (MG), which is an endogenous cancer-static and glycating α-oxoaldehyde, and by rewiring of energy metabolism. Our findings show that not only the ELF magnetic field interfered with the biology of neuron-derived malignant cells, by de-differentiating further the cellular phenotype and by increasing the proliferative activity, but also triggered cytoprotective mechanisms through the enhancement of the defense against MG, along with a more efficient management of metabolic energy, presumably to support the rapid cell outgrowth. Intriguingly, we also revealed that the MF-induced bioeffects took place after an initial imbalance of the cellular homeostasis, which most likely created a transient unstable milieu. The biochemical pathways and molecular targets revealed in this research could be exploited for future approaches aimed at limiting or suppressing the deleterious effects of ELF magnetic fields. J. Cell. Physiol. 231: 2014-2025, 2016. © 2016 Wiley Periodicals, Inc. PMID:26757151

  16. In vivo tracking of neuronal-like cells by magnetic resonance in rabbit models of spinal cord injury

    Ruiping Zhang; Kun Zhang; Jianding Li; Qiang Liu; Jun Xie

    2013-01-01

    In vitro experiments have demonstrated that neuronal-like cells derived from bone marrow mesenchymal stem cells can survive, migrate, integrate and help to restore the function and be-haviors of spinal cord injury models, and that they may serve as a suitable approach to treating spinal cord injury. However, it is very difficult to track transplanted cells in vivo. In this study, we in-jected superparamagnetic iron oxide-labeled neuronal-like cells into the subarachnoid space in a rabbit model of spinal cord injury. At 7 days after celltransplantation, a smal number of dot-shaped low signal intensity shadows were observed in the spinal cord injury region, and at 14 days, the number of these shadows increased on T2-weighted imaging. Perl’s Prussian blue staining de-tected dot-shaped low signal intensity shadows in the spinal cord injury region, indicative of superparamagnetic iron oxide nanoparticle-labeled cells. These findings suggest that transplanted neuronal-like cells derived from bone marrow mesenchymal stem cells can migrate to the spinal cord injury region and can be tracked by magnetic resonance in vivo. Magnetic resonance imaging represents an efficient noninvasive technique for visual y tracking transplanted cells in vivo.

  17. A 1H nuclear magnetic resonance study of structural and organisational changes in the cell

    Increasing importance is being placed on understanding the role of membrane lipids in many different areas of biochemistry. It is of interest to determine what interactions may occur between membrane lipids and drug species. Furthermore, an increasing body of evidence suggests that membrane lipids are involved in the pathology of numerous diseases such as rheumatoid arthritis, cancer and HIV. Clearly, the more information available on the mechanisms involved in diseases, the greater the potential for identifying a cure or even a prevention. 1H nuclear magnetic resonance (NMR) spectroscopy was used to study the alterations in membrane lipid organisation and structure in intact, viable cultured cells. Changes in the 1H NMR spectra and the spin-lattice relaxation measurements of the human K562 and the rat FRTL-5 cell lines were observed on the addition of the fatty acid species: triolein, evening primrose oil, arachidonic acid and ITF 1779. Results indicate that the membrane lipids are reorganised to accommodate the interpolation of these molecules. The spatial arrangement adopted by each of these species appeared to dictate its effect on the lipids. Doxorubicin and menadione, both known to cause oxidative stress, were added to K562 cells. Although both agents are known to act by different mechanisms, the NMR data and scanning electron microscopy suggested that both caused similar alterations in the membrane organisation and lipid fluidity. Protrusions were formed indicating areas of weakness in the membrane. Spin-echo NMR was employed to investigate the action of the thiol-containing compounds, penicillamine, captopril and N-acetylcysteine in erythrocytes under conditions of oxidative stress. Results indicate that while captopril acts as a free radical scavenger, penicillamine may act as either oxidant or reductant. N-acetylcysteine was observed to act as a reducing agent. (author)

  18. Down-regulation of adipogenesis of mesenchymal stem cells by oscillating high-gradient magnetic fields and mechanical vibration

    Zablotskii, V.; Lunov, O.; Novotná, B.; Churpita, O.; Trošan, P.; HoláÅ, V.; Syková, E.; Dejneka, A.; Kubinová, Š.

    2014-09-01

    Nowadays, the focus in medicine on molecular genetics has resulted in a disregard for the physical basis of treatment even though many diseases originate from changes in cellular mechanics. Perturbations of the cellular nanomechanics promote pathologies, including cardiovascular disease and cancer. Furthermore, whilst the biological and therapeutic effects of magnetic fields are a well-established fact, to date the underlying mechanisms remain obscure. Here, we show that oscillating high-gradient magnetic field (HGMF) and mechanical vibration affect adipogenic differentiation of mesenchymal stem cells by the transmission of mechanical stress to the cell cytoskeleton, resulting in F-actin remodelling and subsequent down-regulation of adipogenic genes adiponectin, PPARγ, and AP2. Our findings propose an insight into the regulation of cellular nanomechanics, and provide a basis for better controlled down-regulation of stem cell adipogenesis by HGMF, which may facilitate the development of challenging therapeutic strategies suitable for the remote control of biological systems.

  19. A MICROFLUIDIC MAGNETIC HYBRID ACTUATOR FOR ADVANCED HANDLING FUNCTIONS AT CELL RESOLUTION

    Fouet, Marc; Courson, Rémi; Dollat, Xavier; Medale, Daniel; Gué, Anne-Marie

    2014-01-01

    In microfluidics, the use of super-paramagnetic microparticles (SMPs) has experienced a dramatic increase over the last decade, but control of the magnetic field at micro scale is still a topical issue. Permanent magnets don't offer a programmable approach, external coils require a certain power, and neither are usually integrated. Hybrid systems, which include external magnets to generate a high and homogeneous magnetic field, and integrated coils that produce a high gradient, are seemingly ...

  20. Isolation, purification, culture and characterisation of myoepithelial cells from normal and neoplastic canine mammary glands using a magnetic-activated cell sorting separation system.

    Sánchez-Céspedes, R; Maniscalco, L; Iussich, S; Martignani, E; Guil-Luna, S; De Maria, R; Martín de Las Mulas, J; Millán, Y

    2013-08-01

    Mammary gland tumours, the most common malignant neoplasm in bitches, often display myoepithelial (ME) cell proliferation. The aim of this study was to isolate, purify, culture and characterise ME cells from normal and neoplastic canine mammary glands. Monodispersed cells from three normal canine mammary glands and five canine mammary tumours were incubated with an anti-Thy1 antibody and isolated by magnetic-activated cell sorting (MACS). Cells isolated from two normal glands (cell lines CmME-N1 and CmME-N2) and four tumours (cell lines CmME-K1 from a complex carcinoma, CmME-K2 from a simple tubulopapillary carcinoma, and CmME-K3 and CmME-K4 from two carcinomas within benign tumours) were cultured in supplemented DMEM/F12 media for 40days. Cell purity was >90%. Tumour-derived ME cell lines exhibited heterogeneous morphology, growth patterns and immunocytochemical expression of cytokeratins, whereas cell lines from normal glands retained their morphology and levels of cytokeratin expression during culture. Cell lines from normal glands and carcinomas within benign tumours grew more slowly than those from simple and complex carcinomas. This methodology has the potential to be used for in vitro analysis of the role of ME cells in the growth and progression of canine mammary tumours. PMID:23583698

  1. Homologous RBC-derived vesicles as ultrasmall carriers of iron oxide for magnetic resonance imaging of stem cells

    Chang, Microsugar; Chien, Li-Ying; Yang, Chung-Shi; Huang, Dong-Ming [Center for Nanomedicine Research, National Health Research Institutes, Zhunan, Miaoli County 350, Taiwan (China); Hsiao, Jong-Kai; Liu, Hon-Man [Department of Medical Imaging, National Taiwan University, Taipei, Taiwan (China); Yao, Ming; Ko, Bor-Sheng; Chen, Yao-Chang [Department of Internal Medicine, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan (China); Hsu, Szu-Chun [Department of Laboratory Medicine, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan (China); Chen, Shin-Tai, E-mail: dmhuang@nhri.org.tw [Musculoskeletal Disease Center, J L Pettis VA Medical Center and Department of Biochemistry, Loma Linda University, Loma Linda, CA (United States)

    2010-06-11

    Ultrasmall superparamagnetic iron oxide (USPIO) particles are very useful for cellular magnetic resonance imaging (MRI), which plays a key role in developing successful stem cell therapies. However, their low intracellular labeling efficiency, and biosafety concerns associated with their use, have limited their potential usage. In this study we develop a novel system composed of RBC-derived vesicles (RDVs) for efficient delivery of USPIO particles into human bone marrow mesenchymal stem cells (MSCs) for cellular MRI in vitro and in vivo. RDVs are highly biosafe to their autologous MSCs as manifested by cell viability, differentiation, and gene microarray assays. The data demonstrate the potential of RDVs as intracellular delivery vehicles for biomedical applications.

  2. Dual mode of cancer cell destruction for pancreatic cancer therapy using Hsp90 inhibitor loaded polymeric nano magnetic formulation.

    Rochani, Ankit K; Balasubramanian, Sivakumar; Ravindran Girija, Aswathy; Raveendran, Sreejith; Borah, Ankita; Nagaoka, Yutaka; Nakajima, Yoshikata; Maekawa, Toru; Kumar, D Sakthi

    2016-09-10

    Heat Shock Protein 90 (Hsp90) has been extensively explored as a potential drug target for cancer therapies. 17- N-allylamino- 17-demethoxygeldanamycin (17AAG) was the first Hsp90 inhibitor to enter clinical trials for cancer therapy. However, native drug is being shown to have considerable anticancer efficacy against pancreatic cancer when used in combination therapy regime. Further, magnetic hyperthermia has shown to have promising effects against pancreatic cancer in combination with known cyto-toxic drugs under both target and non-targeted scenarios. Hence, in order to enhance the efficacy of 17AAG against pancreatic cancer, we developed poly (lactic-co-glycolic acid) (PLGA) coated, 17AAG and Fe3O4 loaded magnetic nanoparticle formulations by varying the relative concentration of polymer. We found that polymer concentration affects the magnetic strength and physicochemical properties of formulation. We were also able to see that our aqueous dispensable formulations were able to provide anti-pancreatic cancer activity for MIA PaCa-2 cell line in dose and time dependent manner in comparison to mice fibroblast cell lines (L929). Moreover, the in-vitro magnetic hyperthermia against MIA PaCa-2 provided proof principle that our 2-in-1 particles may work against cancer cell lines effectively. PMID:27469073

  3. Targeting Cells With MR Imaging Probes: Cellular Interaction And Intracellular Magnetic Iron Oxide Nanoparticles Uptake In Brain Capillary Endothelial and Choroidal Plexus Epithelial Cells

    Cambianica, I.; Bossi, M.; Gasco, P.; Gonzalez, W.; Idee, J. M.; Miserocchi, G.; Rigolio, R.; Chanana, M.; Morjan, I.; Wang, D.; Sancini, G.

    2010-10-01

    Magnetic iron oxide nanoparticles (NPs) are considered for various diagnostic and therapeutic applications in brain including their use as contrast agent for magnetic resonance imaging. In delivery application, the critical step is the transport across cell layers and the internalization of NPs into specific cells, a process often limited by poor targeting specificity and low internalization efficiency. The development of the models of brain endothelial cells and choroidal plexus epithelial cells in culture has allowed us to investigate into these mechanisms. Our strategy is aimed at exploring different routes to the entrapment of iron oxide NPs in these brain related cells. Here we demonstrated that not only cells endowed with a good phagocytic activity like activated macrophages but also endothelial brain capillary and choroidal plexus epithelial cells do internalize iron oxide NPs. Our study of the intracellular trafficking of NPs by TEM, and confocal microscopy revealed that NPs are mainly internalized by the endocytic pathway. Iron oxide NPs were dispersed in water and coated with 3,4-dihydroxyl-L-phenylalanine (L-DOPA) using standard procedures. Magnetic lipid NPs were prepared by NANOVECTOR: water in oil in water (W/O/W) microemulsion process has been applied to directly coat different iron based NPs by lipid layer or to encapsulate them into Solid Lipid Nanoparticles (SLNs). By these coating/loading the colloidal stability was improved without strong alteration of the particle size distribution. Magnetic lipid NPs could be reconstituted after freeze drying without appreciable changes in stability. L-DOPA coated NPs are stable in PBS and in MEM (Modified Eagle Medium) medium. The magnetic properties of these NPs were not altered by the coating processes. We investigated the cellular uptake, cytotoxicity, and interaction of these NPs with rat brain capillary endothelial (REB4) and choroidal plexus epithelial (Z310) cells. By means of widefield, confocal

  4. Modeling sickle cell vasoocculsion in the rat leg: Quantification of trapped sickle cells and correlation with 31P metabolic and 1H magnetic resonance imaging changes

    The authors have developed an animal model to elucidate the acute effects of perfusion abnormalities on muscle metabolism induced by different density-defined classes of erythrocytes isolated from sickle cell anemia patients. Technetium-99m (99mTc)-labeled, saline-washed normal (AA), homozygous sickle (SS), or high-density SS (SS4) erythrocytes were injected into the femoral artery of the rat and quantitative 99mTc imaging, 31P magnetic resonance spectroscopy by surface coil at 2 teslas, and 1H magnetic resonance imaging at 0.15 tesla were performed. Between 5 and 25 μl of SS4 cells was trapped in the microcirculation of the thigh. In contrast, fewer SS discocytes (SS2) or AA cells were trapped. After injection of SS4 cells an initial increase in inorganic phosphate was observed in the region of the thigh served by the femoral artery, intracellular pH decreased, and subsequently the proton relaxation time T1 reached a broad maximum at 18-28 hr. When T1 obtained at this time was plotted against the volume of cells trapped, an increase of T1 over the control value of 411 ± 48 msec was found that was proportional to the number of cells trapped. They conclude that the densest SS cells are most effective at producing vasoocclusion. The extent of the change detected by 1H magnetic resonance imaging is dependent on the amount of cells trapped in the microcirculation and the magnitude of the initial increase of inorganic phosphate

  5. Triggering the apoptosis of targeted human renal cancer cells by the vibration of anisotropic magnetic particles attached to the cell membrane

    Leulmi, Selma; Chauchet, Xavier; Morcrette, Melissa; Ortiz, Guillermo; Joisten, Hélène; Sabon, Philippe; Livache, Thierry; Hou, Yanxia; Carrière, Marie; Lequien, Stéphane; Dieny, Bernard

    2015-09-01

    Cancer cells develop resistance to chemotherapy, and the side effects encountered seriously limit the effectiveness of treatments. For these reasons, the search for alternative therapies that target cancer cells without affecting healthy tissues is currently one of the most active areas of research on cancer. The present study focuses on a recently proposed approach for cancer cell destruction based on the targeted triggering of cancer cell spontaneous death through the mechanical vibration of anisotropic magnetic micro/nanoparticles attached to the cell membranes at low frequencies (~20 Hz) and in weak magnetic fields (~30 mT). The study was conducted in vitro, on human renal cancer cells with superparamagnetic-like particles. Three types of such particles made of NiFe or magnetite were prepared and characterized (either synthetic antiferromagnetic, vortex or polycrystalline with random grain anisotropy). The triggering of the apoptosis of these cancer cells was demonstrated with NiFe vortex particles and statistically characterized by flow-cytometry studies. The death pathway via apoptosis and not necrosis was identified by the clear observation of caspase activation.

  6. Safe and efficient method for cryopreservation of human induced pluripotent stem cell-derived neural stem and progenitor cells by a programmed freezer with a magnetic field.

    Nishiyama, Yuichiro; Iwanami, Akio; Kohyama, Jun; Itakura, Go; Kawabata, Soya; Sugai, Keiko; Nishimura, Soraya; Kashiwagi, Rei; Yasutake, Kaori; Isoda, Miho; Matsumoto, Morio; Nakamura, Masaya; Okano, Hideyuki

    2016-06-01

    Stem cells represent a potential cellular resource in the development of regenerative medicine approaches to the treatment of pathologies in which specific cells are degenerated or damaged by genetic abnormality, disease, or injury. Securing sufficient supplies of cells suited to the demands of cell transplantation, however, remains challenging, and the establishment of safe and efficient cell banking procedures is an important goal. Cryopreservation allows the storage of stem cells for prolonged time periods while maintaining them in adequate condition for use in clinical settings. Conventional cryopreservation systems include slow-freezing and vitrification both have advantages and disadvantages in terms of cell viability and/or scalability. In the present study, we developed an advanced slow-freezing technique using a programmed freezer with a magnetic field called Cells Alive System (CAS) and examined its effectiveness on human induced pluripotent stem cell-derived neural stem/progenitor cells (hiPSC-NS/PCs). This system significantly increased cell viability after thawing and had less impact on cellular proliferation and differentiation. We further found that frozen-thawed hiPSC-NS/PCs were comparable with non-frozen ones at the transcriptome level. Given these findings, we suggest that the CAS is useful for hiPSC-NS/PCs banking for clinical uses involving neural disorders and may open new avenues for future regenerative medicine. PMID:26804710

  7. Transcriptional effects of 50 Hz magnetic fields at 1.2 μT and 100 μT on human breast cancer MCF-7 cells

    The International Agency for Research on Cancer (IARC) classified power frequency magnetic fields as a possible human carcinogen. Alteration in transcription programs is a fundamental feature of cancer. Here, using DNA array technology, we examined the transcriptional effects of 50 Hz magnetic fields on human breast cancer MCF-7 cells. It was found that expression of several oncogenes was significantly altered by magnetic-field exposure and that gene expression profilings were similar in MCF-7 cells exposed to magnetic fields at 1.2 μT and 100 μT for 1 week.

  8. Magnetic Fe3O4 nanoparticle catalyzed chemiluminescence for detection of nitric oxide in living cells.

    Wang, Huiliang; Li, Mei; Wang, Bing; Wang, Meng; Kurash, Ibrahim; Zhang, Xiangzhi; Feng, Weiyue

    2016-08-01

    Direct and real-time measurement of nitric oxide (NO) in biological media is very difficult due to its transient nature. Fe3O4 nanoparticles (nanoFe3O4) because of their unique catalytic activities have attracted much attention as catalysts in a variety of organic and inorganic reactions. In this work, we have developed a magnetic Fe3O4 nanoparticle-based rapid-capture system for real-time detection of cellular NO. The basic principle is that the nanoFe3O4 can catalyze the decomposition of H2O2 in the system to generate superoxide anion (O2 (·-)) and the O2 (·-) can serve as an effective NO(·) trapping agent yielding peroxynitrite oxide anion, ONOO(-). Then the concentration of NO in cells can be facilely determined via peroxynitrite-induced luminol chemiluminescence. The linear range of the method is from 10(-4) to 10(-8) mol/L, and the detection of limit (3σ, n = 11) is as low as 3.16 × 10(-9) mol/L. By using this method, the NO concentration in 0.1 and 0.5 mg/L LPS-stimulated BV2 cells was measured as 4.9 and 11.3 μM, respectively. Surface measurements by synchrotron X-ray photoelectron spectroscopy (SRXPS) and scanning transmission X-ray microscopy (STXM) demonstrate the catalytic mechanism of the nanoFe3O4-based system is that the significantly excess Fe(II) exists on the surface of nanoFe3O4 and mediates the rapid heterogeneous electron transfer, thus presenting a new Fe2O3 phase on the surface. PMID:27289465

  9. Particle-in-cell simulation study of the scaling of asymmetric magnetic reconnection with in-plane flow shear

    Doss, C E; Swisdak, M

    2016-01-01

    We investigate magnetic reconnection in systems simultaneously containing asymmetric (anti-parallel) magnetic fields, asymmetric plasma densities and temperatures, and arbitrary in-plane bulk flow of plasma in the upstream regions. Such configurations are common in the high-latitudes of Earth's magnetopause and in tokamaks. We investigate the convection speed of the X-line, the scaling of the reconnection rate, and the condition for which the flow suppresses reconnection as a function of upstream flow speeds. We use two-dimensional particle-in-cell simulations to capture the mixing of plasma in the outflow regions better than is possible in fluid modeling. We perform simulations with asymmetric magnetic fields, simulations with asymmetric densities, and simulations with magnetopause-like parameters where both are asymmetric. For flow speeds below the predicted cutoff velocity, we find good scaling agreement with the theory presented in Doss et al., J.~Geophys.~Res., 120, 7748 (2015). Applications to planetary...

  10. Scaled-down particle-in-cell simulation of cathode plasma expansion in magnetically insulated coaxial diode

    Zhu, Danni; Zhang, Jun; Zhong, Huihuang; Cai, Dan

    2016-03-01

    The expansion of cathode plasma in magnetically insulated coaxial diode (MICD) is investigated in theory and particle-in-cell (PIC) simulation. The temperature and density of the cathode plasma are about several eV and 1013-1016 cm-3, respectively, and its expansion velocity is of the level of few cm/μs. Through hydrodynamic theory analysis, expressions of expansion velocities in axial and radial directions are obtained. The characteristics of cathode plasma expansion have been simulated through scaled-down PIC models. Simulation results indicate that the expansion velocity is dominated by the ratio of plasma density other than the static electric field. The electric field counteracts the plasma expansion reverse of it. The axial guiding magnetic field only reduces the radial transport coefficients by a correction factor, but not the axial ones. Both the outward and inward radial expansions of a MICD are suppressed by the much stronger guiding magnetic field and even cease.

  11. Paramagnetic Gd(3+) labeled red blood cells for magnetic resonance angiography.

    Aryal, Santosh; Stigliano, Cinzia; Key, Jaehong; Ramirez, Maricela; Anderson, Jeff; Karmonik, Christof; Fung, Steve; Decuzzi, Paolo

    2016-08-01

    Despite significant advances in contrast enhanced-magnetic resonance angiography, the lack of truly blood-pool agents with long circulating property is limiting the clinical impact of this imaging technique. The terminal half-life for blood elimination of most small molecular weight gadolinium (Gd) based extracellular fluid agents is about 1.5 h when administered intravenously to subjects with normal renal function. The small size of these extracellular fluid agents does not prevent them from extravasating, especially from damaged vessels which are generally hyperpermeable. Therefore, the development of novel, clinically relevant blood pool contrast agents is critically needed to improve outcomes in the prevention, detection, and treatment of vascular diseases. We have demonstrated the fusion strategies in which the Gd-liposome without any stealth property radically fuses with red blood cells (RBCs) forming MR glowing Gd-RBC with the order of magnitude enhancements in circulation half-life (t1/2 = 50 h) and r1 relaxivity (r1 = 19.0 mM(-1) s(-1)) of Gd. The in vivo contrast enhancement of Gd-RBC was studied by using 3T clinical MR scanner for extended period of time, which clearly visualized the abdominal aorta. In summary, the vascular delivery of blood pool agents may benefit from carriage by RBCs because it naturally stays within the vascular lumen. PMID:27192419

  12. Enhancing malaria diagnosis through microfluidic cell enrichment and magnetic resonance relaxometry detection

    Fook Kong, Tian; Ye, Weijian; Peng, Weng Kung; Wei Hou, Han; Marcos; Preiser, Peter Rainer; Nguyen, Nam-Trung; Han, Jongyoon

    2015-06-01

    Despite significant advancements over the years, there remains an urgent need for low cost diagnostic approaches that allow for rapid, reliable and sensitive detection of malaria parasites in clinical samples. Our previous work has shown that magnetic resonance relaxometry (MRR) is a potentially highly sensitive tool for malaria diagnosis. A key challenge for making MRR based malaria diagnostics suitable for clinical testing is the fact that MRR baseline fluctuation exists between individuals, making it difficult to detect low level parasitemia. To overcome this problem, it is important to establish the MRR baseline of each individual while having the ability to reliably determine any changes that are caused by the infection of malaria parasite. Here we show that an approach that combines the use of microfluidic cell enrichment with a saponin lysis before MRR detection can overcome these challenges and provide the basis for a highly sensitive and reliable diagnostic approach of malaria parasites. Importantly, as little as 0.0005% of ring stage parasites can be detected reliably, making this ideally suited for the detection of malaria parasites in peripheral blood obtained from patients. The approaches used here are envisaged to provide a new malaria diagnosis solution in the near future.

  13. In vivo tracking of magnetically labeled mesenchmal stem cells injected via renal arteries in kidney failure rat

    Objective: To evaluate in vivo depiction and tracking for magnetically labeled bone marrow mesenchymal stern cells (MSCs) in a renal failure rat model injected intravascularly using a 1.5 T magnetic resonance imaging (MRI) system. Methods: Rat MSCs were isolated, purified, expanded and then incubated with home synthesized Fe2O3-PLL. Prussian blue stain was employed for identifying intracellular irons. An acute renal failure in rat was induced by intramuscular injection of glycerol and MSCs were injected into renal arteries of 11 recipients (labeled cells in six, unlabeled cells in five). MR images of kidneys were obtained respectively before injection of MSCs, and immediately, 1, 3, 5, and 8 clays after transplantation. MR imaging findings were analyzed, which were correlated with histological findings. Results: Rat MSCs were successfully labeled, and labeling efficiency was almost 100%. Prussian blue staining of Fe2O3-PLL labeled cells revealed the presence of iron-containing vesicles or endosomes in the cytoplasm. In the renal failure model of rats, the labeled MSCs were demonstrated as signal intensity loss in renal cortex on T2*-weighted MR images. The signal intensity decrease was visualized up to days 8 after transplantation. Histological analyses showed that most Prussian blue staining-positive cells were well correlated with the area where a signal intensity loss was observed in MRI. Signal intensity decrease was not detected after transplantation of unlabeled cells. Conclusion: The rat MSCs can be effectively labeled with Fe2O3-PLL. 1.5-T MR imaging seems to be a good technique to monitor the magnetically labeled MSCs in vivo in renal failure rat model intravascularly administered, which may have much more potential values for studying the engraftment of stem cells in kidneys. (authors)

  14. Transport, compartmentation, and metabolism of homoserine in higher plant cells. Carbon-13- and phosphorus-31-nuclear magnetic resonance studies

    The transport, compartmentation, and metabolism of homoserine was characterized in two strains of meristematic higher plant cells, the dicotyledonous sycamore (Acer pseudoplatanus) and the monocotyledonous weed Echinochloa colonum. Homoserine is an intermediate in the synthesis of the aspartate-derived amino acids methionine, threonine (Thr), and isoleucine. Using 13C-nuclear magnetic resonance, we showed that homoserine actively entered the cells via a high-affinity proton-symport carrier (K(m) approximately 50-60 micromolar) at the maximum rate of 8 +/- 0.5 micromol h-1 g-1 cell wet weight, and in competition with serine or Thr. We could visualize the compartmentation of homoserine, and observed that it accumulated at a concentration 4 to 5 times higher in the cytoplasm than in the large vacuolar compartment. 31P-nuclear magnetic resonance permitted us to analyze the phosphorylation of homoserine. When sycamore cells were incubated with 100 micromolar homoserine, phosphohomoserine steadily accumulated in the cytoplasmic compartment over 24 h at the constant rate of 0.7 micromol h-1 g-1 cell wet weight, indicating that homoserine kinase was not inhibited in vivo by its product, phosphohomoserine. The rate of metabolism of phosphohomoserine was much lower (0.06 micromol h-1 g-1 cell wet weight) and essentially sustained Thr accumulation. Similarly, homoserine was actively incorporated by E. colonum cells. However, in contrast to what was seen in sycamore cells, large accumulations of Thr were observed, whereas the intracellular concentration of homoserine remained low, and phosphohomoserine did not accumulate. These differences with sycamore cells were attributed to the presence of a higher Thr synthase activity in this strain of monocot cells

  15. Enrichment of Fetal Nucleated Red Blood Cells by Multi-core Magnetic Composite Particles for Non-invasive Prenatal Diagnosis

    PAN Ying; ZHANG Ai-chen; WANG Qing; HUANG Wen-jun; QIAO Feng-li; LIU Yu-ping; ZHANG Yu-cheng; HAl De-yang; DU Ying-ting; WANG Wen-yue

    2012-01-01

    A novel kind of multi-core magnetic composite particles,the surfaces of which were respectively modified with goat-anti-mouse IgG and antitransferrin receptor(anti-CD71 ),was prepared.The fetal nucleated red blood cells(FNRBCs) in the peripheral blood of a gravida were rapidly and effectively enriched and separated by the modified multi-core magnetic composite particles in an external magnetic field.The obtained FNRBCs were used for the identification of the fetal sex by means of fluorescence in situ hybridization(FISH) technique.The results demonstrate that the multi-core magnetic composite particles meet the requirements for the enrichment and speration of FNRBCs with a low concentration and the accuracy of detetion for the diagnosis of fetal sex reached to 95%.Moreover,the obtained FNRBCs were applied to the non-invasive diagnosis of Down syndrome and chromosome 3p21 was detected.The above facts indicate that the novel multi-core magnetic composite particles-based method is simple,reliable and cost-effective and has opened up vast vistas for the potential application in clinic non-invasive prenatal diagnosis.

  16. Quantification of choline concentration following liver cell apoptosis using 1H magnetic resonance spectroscopy

    Zhi-Wei Shen; Zhen Cao; Ke-Zeng You; Zhong-Xian Yang; Ye-Yu Xiao; Xiao-Fang Cheng; Yao-Wen Chen

    2012-01-01

    AIM:To evaluate the feasibility of quantifying liver choline concentrations in both normal and apoptotic rabbit livers in vivo,using 1H magnetic resonance spectroscopy (1H-MRS).METHODS:1H-MRS was performed in 18 rabbits using a 1.5T GE MR system with an eight-channel head/neck receiving coil.Fifteen rabbits were injected with sodium selenite at a dose of 10 μmol/kg to induce the liver cell apoptosis.Point-resolved spectroscopy sequencelocalized spectra were obtained from 10 livers once before and once 24 h after sodium selenite injection in vivo.T1 and T2 relaxation time of water and choline was measured separately in the livers of three healthy rabbits and three selenite-treated rabbits.Hematoxylin and eosin and dUTP-biotin nick end labeling (TUNEL) staining was used to detect and confirm apoptosis.Choline peak areas were measured relative to unsuppressed water using LCModel.Relaxation attenuation was corrected using the average of T1 and T2 relaxation time.The choline concentration was quantified using a formula,which was tested by a phantom with a known concentration.RESULTS:Apoptosis of hepatic cells was confirmed by TUNEL assay.In phantom experiment,the choline concentration (3.01 mmol/L),measured by 1H-MRS,was in good agreement with the actual concentration (3 mmol/L).The average T1 and T2 relaxation time of choline was 612 ± 15 ms and 74 ± 4 ms in the control group and 670 ± 27 ms and 78 ± 5 ms in apoptotic livers in vivo,respectively.Choline was quantified in 10 rabbits,once before and once after the injection with sodium selenite.The choline concentration decreased from 14.5 ± 7.57 mmol/L before sodium selenite injection to 10.8 ± 6.58 mmol/L (mean ± SD,n =10) after treatment (Z =-2.395,P < 0.05,two-sample paired Wilcoxon test).CONCLUSION:1H-MRS can be used to quantify liver choline in vivo using unsuppressed water as an internal reference.Decreased liver choline concentrations are found in sodium selenite-treated rabbits undergoing liver cell

  17. Magnetomotive photoacoustic imaging: in vitro studies of magnetic trapping with simultaneous photoacoustic detection of rare circulating tumor cells.

    Wei, Chen-wei; Xia, Jinjun; Pelivanov, Ivan; Jia, Congxian; Huang, Sheng-Wen; Hu, Xiaoge; Gao, Xiaohu; O'Donnell, Matthew

    2013-06-01

    Photoacoustic (PA) imaging has been demonstrated to be a promising modality in molecular imaging for detection of nanoparticle-targeted diseased cells or tissues. However, intrinsic absorbers, such as blood, produce strong PA background signals that severely degrade the detection sensitivity and specificity of targeted objects. Magnetomotive photoacoustic (mmPA) imaging, a newly developed molecular imaging modality, introduced dynamic manipulation into traditional PA imaging. Unlike conventional PA imaging, magnetomotive manipulation with simultaneous ultrasound/PA imaging of agents incorporating magnetic nanoparticles enables direct visualization of the signal generating object and can dramatically reduce background signals from strong optical absorbers. This paper briefly reviews recent developments in mmPA imaging, including uses of composite contrast agent, design of magnet system, and data processing for motion filtering. The use of mmPA imaging in detecting rare circulating tumor cells in blood vessels, which remains a big challenge for real-time in vivo examination using current methodologies, was also addressed. PMID:23420803

  18. An experimental and numerical investigation of flat panel display cell using magnetic fluid

    Seo, J W; Park, S J; Lee, H S

    2002-01-01

    Optical and fluid dynamical properties of magnetic fluid have been studied experimentally and numerically using a test device with a water-base magnetite magnetic fluid. It has been found that the 3.5 mu m thick fluid film absorbs most of the incoming visible light and can be actuated fast enough to realize display devices. The computational simulation shows that the surface tension of the liquid plays the most dominant roles for the test device, and a device that can actuate the magnetic fluid magnetically is proposed.

  19. Ewing sarcoma dissemination and response to T-cell therapy in mice assessed by whole-body magnetic resonance imaging

    Liebsch, L; Kailayangiri, S; Beck, L; Altvater, B; R. Koch; Dierkes, C. (Christian); Hotfilder, M; Nagelmann, N.; Faber, C.; Kooijman, H.; Ring, J.; Vieth, V.; Rossig, C.

    2013-01-01

    Background: Novel treatment strategies in Ewing sarcoma include targeted cellular therapies. Preclinical in vivo models are needed that reflect their activity against systemic (micro)metastatic disease. Methods: Whole-body magnetic resonance imaging (WB-MRI) was used to monitor the engraftment and dissemination of human Ewing sarcoma xenografts in mice. In this model, we evaluated the therapeutic efficacy of T cells redirected against the Ewing sarcoma-associated antigen GD2 by chimeric recep...

  20. Intra-unit-cell magnetic correlations near optimal doping in YBa2Cu3O6.85.

    Mangin-Thro, L; Sidis, Y; Wildes, A; Bourges, P

    2015-01-01

    The pseudo-gap phenomenon in copper oxide superconductors is central to any description of these materials as it prefigures the superconducting state itself. A magnetic intra-unit-cell order was found to occur just at the pseudo-gap temperature in four cuprate high-Tc superconducting families. Here we present polarized neutron-scattering measurements of nearly optimally doped YBa2Cu3O6.85, carried out on two different spectrometers, that reveal several features. The intra-unit-cell order consists of finite-sized planar domains that are very weakly correlated along the c axis. At high temperature, only the out-of-plane magnetic components correlate, indicating a strong Ising anisotropy. An aditional in-plane response develops at low temperature, giving rise to an apparent tilt of the magnetic moment. The discovery of these two regimes puts stringent constraints, which are tightly bound to the pseudo-gap physics, on the intrinsic nature of intra-unit-cell order. PMID:26138869

  1. Intra-unit-cell magnetic correlations near optimal doping in YBa2Cu3O6.85

    Mangin-Thro, L.; Sidis, Y.; Wildes, A.; Bourges, P.

    2015-07-01

    The pseudo-gap phenomenon in copper oxide superconductors is central to any description of these materials as it prefigures the superconducting state itself. A magnetic intra-unit-cell order was found to occur just at the pseudo-gap temperature in four cuprate high-Tc superconducting families. Here we present polarized neutron-scattering measurements of nearly optimally doped YBa2Cu3O6.85, carried out on two different spectrometers, that reveal several features. The intra-unit-cell order consists of finite-sized planar domains that are very weakly correlated along the c axis. At high temperature, only the out-of-plane magnetic components correlate, indicating a strong Ising anisotropy. An aditional in-plane response develops at low temperature, giving rise to an apparent tilt of the magnetic moment. The discovery of these two regimes puts stringent constraints, which are tightly bound to the pseudo-gap physics, on the intrinsic nature of intra-unit-cell order.

  2. Down-regulation of adipogenesis of mesenchymal stem cells by oscillating high-gradient magnetic fields and mechanical vibration

    Zablotskyy, Vitaliy A.; Lunov, Oleg; Novotná, Božena; Churpita, Olexandr; Trošan, Peter; Holáň, Vladimír; Syková, Eva; Dejneka, Alexandr; Kubinová, Šárka

    2014-01-01

    Roč. 105, č. 10 (2014), "103702-1"-"103702-4". ISSN 0003-6951 R&D Projects: GA ČR GAP304/11/0653; GA ČR(CZ) GAP304/12/1370; GA MŠk LO1309 Grant ostatní: AV ČR(CZ) M100101219 Institutional support: RVO:68378271 ; RVO:68378041 Keywords : stem cells * cytoskeleton * magnetic field * cell growth Subject RIV: BO - Biophysics; FH - Neurology (UEM-P) Impact factor: 3.302, year: 2014

  3. Development of a tapered cell drift chamber II: operation in high magnetic fields and different gas pressures

    Several designs for drift cells have been constructed and tested in an electron beam at DESY. The designs tested consisted of pairs of adjacent tapered cells, of eight sense wires each, to simulate a portion of a layer of drift cells in a central tracking detector. Tests were made to study the operation and resolution of the drift cells under a variety of conditions. Ar:C2H6 (50:50) and Ar:CO2:CH4 (90:9:1) gas mixtures were used at absolute pressures of one to four bar for the former and at one bar for the latter. Measurements were made at different electric drift fields in conjunction with magnetic fields varying from 0 to 1.82 T. Aspects of the construction, electronics and operation are discussed and results regarding the resolution as a function of drift distance and operating conditions are presented with some model calculations. (author)

  4. Cardiac Sarcoidosis or Giant Cell Myocarditis? On Treatment Improvement of Fulminant Myocarditis as Demonstrated by Cardiovascular Magnetic Resonance Imaging

    Hari Bogabathina

    2012-01-01

    Full Text Available Giant cell myocarditis, but not cardiac sarcoidosis, is known to cause fulminant myocarditis resulting in severe heart failure. However, giant cell myocarditis and cardiac sarcoidosis are pathologically similar, and attempts at pathological differentiation between the two remain difficult. We are presenting a case of fulminant myocarditis that has pathological features suggestive of cardiac sarcoidosis, but clinically mimicking giant cell myocarditis. This patient was treated with cyclosporine and prednisone and recovered well. This case we believe challenges our current understanding of these intertwined conditions. By obtaining a sense of severity of cardiac involvement via delayed hyperenhancement of cardiac magnetic resonance imaging, we were more inclined to treat this patient as giant cell myocarditis with cyclosporine. This resulted in excellent improvement of patient’s cardiac function as shown by delayed hyperenhancement images, early perfusion images, and SSFP videos.

  5. In situ Cell for Mossbauer Spectroscopy between 5 and 800 K in Applied Magnetic Fields

    Bødker, Franz; Mørup, Steen

    Mossbauer studies in large applied magnetic fields. The samples can also be separated from the gas-manifold for long term storage in a controlled enviroment and for studies by other experimental techniques such as magnetic measurements. The application of this system is illustrated by results of...

  6. Acute and chronic effects of exposure to a 1-mT magnetic field on the cytoskeleton, stress proteins, and proliferation of astroglial cells in culture

    This paper reports the effects of exposure to static, sinusoidal (50 Hz), and combined static/sinusoidal magnetic fields on cultured astroglial cells. Confluent primary cultures of astroglial cells were exposed to a 1-mT sinusoidal, static, or combined magnetic field for 1 h. In another experiment, cells were exposed to the combined magnetic field for 1, 2, and 4 h. The hsp25, hsp60, hsp70, actin, and glial fibrillary acidic protein contents of the astroglial cells were determined by immunoblotting 24 h after exposure. No significant differences were seen between control and exposed cells with respect to their contents of these proteins, neither were any changes in cell morphology observed. In a third experiment to determine the effect of a chronic (11-day) exposure to a combined 1-mT static/sinusoidal magnetic field on the proliferation of cultured astroglial cells, no significant differences were seen between control, sham-exposed, or exposed cells. These results suggest that exposure to 1-mT sinusoidal, static, or combined magnetic fields has no significant effects on the stress, cytoskeletal protein levels in, or proliferation of cultured astroglial cells

  7. Planar integrated magnetics design in wide input range DC-DC converter for fuel cell application

    Ouyang, Ziwei; Zhang, Zhe; Thomsen, Ole Cornelius;

    2010-01-01

    In the most power electronics converters, the overall volume is mainly determined by the number of parts and the size of passive components. Integrated magnetics and planar magnetics techniques therefore have been an excellent option in order to reduce the count and the size of magnetic components......, hereby increasing the power density of converters. A new planar integrated magnetics (PIM) technique for a phase-shift plus duty cycle controlled hybrid bi-directional DC/DC converter is presented and investigated in this paper. The main magnetic components including one boost inductor and two...... independent transformers are integrated into an E-I-E core geometry. Utilizing the flux cancellation as the principle of uncoupling, the transformers and the boost inductor are integrated, to reduce the total ferrite volume and core loss. The transformers and inductor are wound in the outer legs and the...

  8. Preoperative radiotherapy in rectal signet-ring cell carcinoma - magnetic resonance imaging and treatment outcome

    Background. Signet-ring cell carcinoma (SRCC) is an uncommon tumor entity in rectal cancer, often considered to be resistant to non-surgical therapy. In locally advanced primary or recurrent rectal cancer, diagnostic information from magnetic resonance imaging (MRI) is considered superior in planning the optimal treatment strategy, which usually includes preoperative radiotherapy. The recognition of MRI features that correlate with the radiation response might ultimately be used to select patients for tailored treatment and, in addition, avoid potentially toxic therapy in non-responding patients. Material and methods. In a cohort of 120 rectal cancer patients who had received preoperative radiotherapy (50 Gy in 2 Gy fractions), six patients were noted to have SRCC tumor differentiation. Initial diagnostic MRI examination included assessment of local T- and N-stage and tumor morphology. Histological tumor response was subsequently assessed in the resected specimens, and postoperative follow-up data was compiled until disease recurrence. Results. Following the preoperative radiotherapy, two distinctly different histological responses - complete response (ypT0N0) or no response - were observed. Extensive mesorectal lymph node metastasis (N2 disease) at the pretreatment MRI examination was unambiguously associated with lack of response and rapid development of disseminated disease. Importantly, patients with complete response have been observed for 23-52 months postoperatively without evidence of recurrent disease. Discussion. Our review may suggest that patients with locally advanced growth of rectal SRCC, despite poorer outcome when compared to patients with conventional-type rectal adenocarcinoma, when presenting limited lymph node disease should be offered preoperative radiotherapy in a tentatively curative setting

  9. 3D modelling of magnetic field and light concentration effects on a bifacial silicon solar cell illuminated by its rear side

    According to their installation places, the solar cells are often under the effect of the electro-magnetic field coming from outside sources as telecommunication antennas, radio antennas... These magnetic fields have a big influence on the distribution and mobility of charge carriers in the base of the solar cell and therefore on its efficiency. This work presents a tree-dimensional study of bifacial silicon solar cell under intense light concentration (more than 50 suns) and under a constant magnetic field. This approach is based on the resolution of the minority continuity equation, taking into account the distribution of the electric field in the bulk evaluated as a function of both majority and minority carrier densities. In this approach new analytical expression of carrier's density is established for rear side illumination. The effects of light concentration and magnetic field on excess minority carriers distribution, photocurrent and photovoltage in solar cell base are analysed.

  10. 3D modelling of magnetic field and light concentration effects on a bifacial silicon solar cell illuminated by its rear side

    Zoungrana, M.; Zerbo, I.; Ouédraogo, F.; Zouma, B.; Zougmoré, F.

    2012-02-01

    According to their installation places, the solar cells are often under the effect of the electro-magnetic field coming from outside sources as telecommunication antennas, radio antennas... These magnetic fields have a big influence on the distribution and mobility of charge carriers in the base of the solar cell and therefore on its efficiency. This work presents a tree-dimensional study of bifacial silicon solar cell under intense light concentration (more than 50 suns) and under a constant magnetic field. This approach is based on the resolution of the minority continuity equation, taking into account the distribution of the electric field in the bulk evaluated as a function of both majority and minority carrier densities. In this approach new analytical expression of carrier's density is established for rear side illumination. The effects of light concentration and magnetic field on excess minority carriers distribution, photocurrent and photovoltage in solar cell base are analysed.

  11. Sequential Enrichment with Titania-coated Magnetic Mesoporous Hollow Silica Microspheres and Zirconium Arsenate-modified Magnetic Nanoparticles for the Study of Phosphoproteome of HL60 Cells

    Yu, Qiong-Wei; Li, Xiao-Shui; Xiao, Yongsheng; Guo, Lei; Zhang, Fan; Cai, Qian; Feng, Yu-Qi; Yuan, Bi-Feng; Wang, Yinsheng

    2014-01-01

    As one of the most important types of post-translational modifications, reversible phosphorylation of proteins plays crucial roles in a large number of biological processes. However, owing to the relatively low abundance and dynamic nature of phosphorylation and the presence of the unphosphorylated peptides in large excess, phosphopeptide enrichment is indispensable in large-scale phosphoproteomic analysis. Metal oxides including titanium dioxide have become prominent affinity materials to enrich phosphopeptides prior to their analysis using liquid chromatography-mass spectrometry (LC-MS). In the current study, we established a novel strategy, which encompassed strong cation exchange chromatography, sequential enrichment of phosphopeptides using titania-coated magnetic mesoporous hollow silica microspheres (TiO2/MHMSS) and zirconium arsenate-modified magnetic nanoparticles (ZrAs-Fe3O4@SiO2), and LC-MS/MS analysis, for the proteome-wide identification of phosphosites of proteins in HL60 cells. In total, we were able to identify 11579 unique phosphorylation sites in 3432 unique proteins. Additionally, our results suggested that TiO2/MHMSS and ZrAs-Fe3O4@SiO2 are complementary in phosphopeptide enrichment, where the two types of materials displayed preferential binding of peptides carrying multiple and single phosphorylation sites, respectively. PMID:25262027

  12. Therapeutic mechanism of treating SMMC-7721 liver cancer cells with magnetic fluid hyperthermia using Fe2O3 nanoparticles

    S.Y. Yan

    2014-11-01

    Full Text Available This study aimed to investigate the therapeutic mechanism of treating SMMC-7721 liver cancer cells with magnetic fluid hyperthermia (MFH using Fe2O3 nanoparticles. Hepatocarcinoma SMMC-7721 cells cultured in vitro were treated with ferrofluid containing Fe2O3 nanoparticles and irradiated with an alternating radio frequency magnetic field. The influence of the treatment on the cells was examined by inverted microscopy, MTT and flow cytometry. To study the therapeutic mechanism of the Fe2O3 MFH, Hsp70, Bax, Bcl-2 and p53 were detected by immunocytochemistry and reverse transcription polymerase chain reaction (RT-PCR. It was shown that Fe2O3 MFH could cause cellular necrosis, induce cellular apoptosis, and significantly inhibit cellular growth, all of which appeared to be dependent on the concentration of the Fe2O3 nanoparticles. Immunocytochemistry results showed that MFH could induce high expression of Hsp70 and Bax, decrease the expression of mutant p53, and had little effect on Bcl-2. RT-PCR indicated that Hsp70 expression was high in the early stage of MFH (<24 h and became low or absent after 24 h of MFH treatment. It can be concluded that Fe2O3 MFH significantly inhibited the proliferation of in vitro cultured liver cancer cells (SMMC-7721, induced cell apoptosis and arrested the cell cycle at the G2/M phase. Fe2O3 MFH can induce high Hsp70 expression at an early stage, enhance the expression of Bax, and decrease the expression of mutant p53, which promotes the apoptosis of tumor cells.

  13. Therapeutic mechanism of treating SMMC-7721 liver cancer cells with magnetic fluid hyperthermia using Fe₂O₃ nanoparticles.

    Yan, S Y; Chen, M M; Fan, J G; Wang, Y Q; Du, Y Q; Hu, Y; Xu, L M

    2014-11-01

    This study aimed to investigate the therapeutic mechanism of treating SMMC-7721 liver cancer cells with magnetic fluid hyperthermia (MFH) using Fe₂O₃ nanoparticles. Hepatocarcinoma SMMC-7721 cells cultured in vitro were treated with ferrofluid containing Fe₂O₃ nanoparticles and irradiated with an alternating radio frequency magnetic field. The influence of the treatment on the cells was examined by inverted microscopy, MTT and flow cytometry. To study the therapeutic mechanism of the Fe₂O₃ MFH, Hsp70, Bax, Bcl-2 and p53 were detected by immunocytochemistry and reverse transcription polymerase chain reaction (RT-PCR). It was shown that Fe₂O₃ MFH could cause cellular necrosis, induce cellular apoptosis, and significantly inhibit cellular growth, all of which appeared to be dependent on the concentration of the Fe₂O₃nanoparticles. Immunocytochemistry results showed that MFH could induce high expression of Hsp70 and Bax, decrease the expression of mutant p53, and had little effect on Bcl-2. RT-PCR indicated that Hsp70 expression was high in the early stage of MFH (<24 h) and became low or absent after 24 h of MFH treatment. It can be concluded that Fe₂O₃MFH significantly inhibited the proliferation of in vitro cultured liver cancer cells (SMMC-7721), induced cell apoptosis and arrested the cell cycle at the G₂/M phase. Fe₂O₃ MFH can induce high Hsp70 expression at an early stage, enhance the expression of Bax, and decrease the expression of mutant p53, which promotes the apoptosis of tumor cells. PMID:25296356

  14. Therapeutic mechanism of treating SMMC-7721 liver cancer cells with magnetic fluid hyperthermia using Fe2O3 nanoparticles.

    Yan, S Y; Chen, M M; Fan, J G; Wang, Y Q; Du, Y Q; Hu, Y; Xu, L M

    2014-08-29

    This study aimed to investigate the therapeutic mechanism of treating SMMC-7721 liver cancer cells with magnetic fluid hyperthermia (MFH) using Fe2O3 nanoparticles. Hepatocarcinoma SMMC-7721 cells cultured in vitro were treated with ferrofluid containing Fe2O3 nanoparticles and irradiated with an alternating radio frequency magnetic field. The influence of the treatment on the cells was examined by inverted microscopy, MTT and flow cytometry. To study the therapeutic mechanism of the Fe2O3 MFH, Hsp70, Bax, Bcl-2 and p53 were detected by immunocytochemistry and reverse transcription polymerase chain reaction (RT-PCR). It was shown that Fe2O3 MFH could cause cellular necrosis, induce cellular apoptosis, and significantly inhibit cellular growth, all of which appeared to be dependent on the concentration of the Fe2O3 nanoparticles. Immunocytochemistry results showed that MFH could induce high expression of Hsp70 and Bax, decrease the expression of mutant p53, and had little effect on Bcl-2. RT-PCR indicated that Hsp70 expression was high in the early stage of MFH (<24 h) and became low or absent after 24 h of MFH treatment. It can be concluded that Fe2O3 MFH significantly inhibited the proliferation of in vitro cultured liver cancer cells (SMMC-7721), induced cell apoptosis and arrested the cell cycle at the G2/M phase. Fe2O3 MFH can induce high Hsp70 expression at an early stage, enhance the expression of Bax, and decrease the expression of mutant p53, which promotes the apoptosis of tumor cells. PMID:25184378

  15. Therapeutic mechanism of treating SMMC-7721 liver cancer cells with magnetic fluid hyperthermia using Fe2O3 nanoparticles

    This study aimed to investigate the therapeutic mechanism of treating SMMC-7721 liver cancer cells with magnetic fluid hyperthermia (MFH) using Fe2O3 nanoparticles. Hepatocarcinoma SMMC-7721 cells cultured in vitro were treated with ferrofluid containing Fe2O3 nanoparticles and irradiated with an alternating radio frequency magnetic field. The influence of the treatment on the cells was examined by inverted microscopy, MTT and flow cytometry. To study the therapeutic mechanism of the Fe2O3 MFH, Hsp70, Bax, Bcl-2 and p53 were detected by immunocytochemistry and reverse transcription polymerase chain reaction (RT-PCR). It was shown that Fe2O3 MFH could cause cellular necrosis, induce cellular apoptosis, and significantly inhibit cellular growth, all of which appeared to be dependent on the concentration of the Fe2O3 nanoparticles. Immunocytochemistry results showed that MFH could induce high expression of Hsp70 and Bax, decrease the expression of mutant p53, and had little effect on Bcl-2. RT-PCR indicated that Hsp70 expression was high in the early stage of MFH (,24 h) and became low or absent after 24 h of MFH treatment. It can be concluded that Fe2O3 MFH significantly inhibited the proliferation of in vitro cultured liver cancer cells (SMMC-7721), induced cell apoptosis and arrested the cell cycle at the G2/M phase. Fe2O3 MFH can induce high Hsp70 expression at an early stage, enhance the expression of Bax, and decrease the expression of mutant p53, which promotes the apoptosis of tumor cells. (author)

  16. Geometric origin of magnetic frustration in the μ-Al4Mn giant-unit-cell complex intermetallic

    The structurally ordered μ-Al4Mn complex intermetallic phase with 563 atoms in the giant unit cell shows the typical broken-ergodicity phenomena of a magnetically frustrated spin system. The low-field zero-field-cooled and field-cooled magnetic susceptibilities show splitting below the spin freezing temperature Tf = 2.7 K. The ac susceptibility exhibits a frequency-dependent cusp, associated with a frequency-dependent freezing temperature Tf(ν). The decay of the thermoremnant magnetization is logarithmically slow in time and shows a dependence on the aging time tw and the cooling field Hfc typical of an ultraslow out-of-equilibrium dynamics of a nonergodic spin system that approaches thermal equilibrium, but can never reach it on the experimentally accessible time scale. The above features classify the μ-Al4Mn complex intermettalic among spin glasses. The origin of frustration of magnetic interactions was found to be geometrical due to the distribution of a significant fraction of Mn spins on triangles with antiferromagnetic coupling. The μ-Al4Mn phase is a geometrically frustrated spin glass.

  17. Magnetic and electrical properties of the R(Co, Si)2 compounds (R=Gd, Tb, Dy) with invariable crystal unit cell parameters

    The invariable crystal unit cell parameter compounds R(Co, Si)2 (R=Gd, Tb and Dy) have been studied by mean of the magnetization, ac susceptibility and resistivity measurements. By partial substitution Co by Si, the ordering temperature is almost constant for all of the considered compounds, whereas the reduction of the 3d magnetic moment is observed. In the condition of fixed volume, these findings suggest the important effects of the hybridization between the 3d states of Co and the p states of Si. The anomalies of magnetization, susceptibility, resistivity and the character of the magnetic phase transition at TC are also discussed for the compounds with Dy. (orig.)

  18. Magnetic transducer

    A description is given of a transducer system for identifying the presence and location of ferromagnetic materials and ferromagnetic discontinuities associated with a sample. This equipment includes a first source of a magnetic field in magnetic connection with the surface of the sample and so mounted that it may be moved along this surface and a Hall effect cell in magnetic connection with the first source, in a fixed position in relation to this first source and placed so as to be in magnetic connection with the sample. The object of this invention is a transducer able to detect the accumulation of corrosion products (scale) on the outer surfaces of steam generator tubes

  19. Action of 50 Hz magnetic fields on cyclic AMP and intercellular communication in monolayers and spheroids of mammalian cells

    Schimmelpfeng, J.; Stein, J.C.; Dertinger, H. [Research Center Karlsruhe (Germany). Inst. of Toxicology

    1995-12-31

    To investigate the influence of physiological parameters such as cell density and three-dimensional cell contact on the biological action of a 2mT/50 Hz magnetic field, mouse fibroblasts were exposed as monolayers and as multicellular spheroids. Changes in cyclic AMP content of cells and alterations in gap junction-mediated intercellular communication were measured immediately after 5 min of exposure to the field. In monolayers of intermediate cell density (1 {times} 10{sup 5} cells/cm{sup 2}), the field treatment caused an increase in cAMP to 121% of the control level, whereas, at 3 {times} 10{sup 5} cells/cm{sup 2} (near confluence), a decrease to 88% of the unexposed cells was observed. Furthermore, field exposure stimulated gap-junction communication to 160% of the control level as determined by Lucifer yellow dye exchange. In spheroids, alterations in the radial profile of cellular cAMP were observed that were due both to field-induced local cAMP changes and to increased gap-junction permeability for this second messenger, the latter causing radial cAMP gradients to be flattened. The results indicate a strong dependence of field action on physiological parameters of the system exposed.

  20. Biofunctionalized magnetic nanospheres-based cell sorting strategy for efficient isolation, detection and subtype analyses of heterogeneous circulating hepatocellular carcinoma cells.

    Chen, Lan; Wu, Ling-Ling; Zhang, Zhi-Ling; Hu, Jiao; Tang, Man; Qi, Chu-Bo; Li, Na; Pang, Dai-Wen

    2016-11-15

    Hepatocellular carcinoma (HCC) is an awful threat to human health. Early-stage HCC may be detected by isolation of circulating tumor cells (CTCs) from peripheral blood samples, which is beneficial to the diagnosis and therapy. However, the extreme rarity and high heterogeneity of HCC CTCs have been restricting the relevant research. To achieve an efficient isolation, reliable detection and subtype analyses of heterogeneous HCC CTCs, herein, we present a cell sorting strategy based on anti-CD45 antibody-modified magnetic nanospheres. By this strategy, leukocyte depletion efficiency was up to 99.9% within 30min in mimic clinical samples, and the purity of the spiked HCC cells was improved 265-317-fold. Besides, the isolated HCC cells remained viable at 92.3% and could be directly recultured. Moreover, coupling the convenient, fast and effective cell sorting strategy with specific ICC identification via biomarkers AFP and GPC3, HCC CTCs were detectable in peripheral blood samples, showing the potential for HCC CTC detection in clinic. Notably, this immunomagnetic cell sorting strategy enabled isolating more heterogeneous HCC cells compared with the established EpCAM-based methods, and further achieved characterization of three different CTC subtypes from one clinical HCC blood sample, which may assist clinical HCC analyses such as prognosis or personalized treatment. PMID:27240010

  1. Increased cellular uptake of biocompatible superparamagnetic iron oxide nanoparticles into malignant cells by an external magnetic field.

    Prijic, Sara; Scancar, Janez; Romih, Rok; Cemazar, Maja; Bregar, Vladimir B; Znidarsic, Andrej; Sersa, Gregor

    2010-07-01

    Superparamagnetic iron oxide nanoparticles (SPIONs) are used as delivery systems for different therapeutics including nucleic acids for magnetofection-mediated gene therapy. The aim of our study was to evaluate physicochemical properties, biocompatibility, cellular uptake and trafficking pathways of the custom-synthesized SPIONs for their potential use in magnetofection. Custom-synthesized SPIONs were tested for size, shape, crystalline composition and magnetic behavior using a transmission electron microscope, X-ray diffractometer and magnetometer. SPIONs were dispersed in different aqueous media to obtain ferrofluids, which were tested for pH and stability using a pH meter and zetameter. Cytotoxicity was determined using the MTS and clonogenic assays. Cellular uptake and trafficking pathways were qualitatively evaluated by transmission electron microscopy and quantitatively by inductively coupled plasma atomic emission spectrometry. SPIONs were composed of an iron oxide core with a diameter of 8-9 nm, coated with a 2-nm-thick layer of silica. SPIONs, dispersed in 0.9% NaCl solution, resulted in a stable ferrofluid at physiological pH for several months. SPIONs were not cytotoxic in a broad range of concentrations and were readily internalized into different cells by endocytosis. Exposure to neodymium-iron-boron magnets significantly increased the cellular uptake of SPIONs, predominantly into malignant cells. The prepared SPIONs displayed adequate physicochemical and biomedical properties for potential use in magnetofection. Their cellular uptake was dependent on the cell type, and their accumulation within the cells was dependent on the duration of exposure to an external magnetic field. PMID:20602230

  2. The magnetic field of Betelgeuse: a local dynamo from giant convection cells?

    Auriere, M.; Donati, J.-F.; Konstantinova-Antova, R.; Perrin, G.; Petit, P.; Roudier, T.

    2010-01-01

    Betelgeuse is an M supergiant with a complex and extended atmosphere, which also harbors spots and giant granules at its surface. A possible magnetic field could contribute to the mass loss and to the heating of the outer atmosphere. We observed Betelgeuse, to directly study and infer the nature of its magnetic field. We used the new-generation spectropolarimeter NARVAL and the least square deconvolution (LSD) method to detect circular polarization within the photospheric absorption lines of ...

  3. Enhanced reduction in cell viability by hyperthermia induced by magnetic nanoparticles

    Héctor L Rodríguez-Luccioni; Magda Latorre-Esteves; Janet Méndez-Vega; et al

    2011-01-01

    Héctor L Rodríguez-Luccioni, Magda Latorre-Esteves, Janet Méndez-Vega, Orlando Soto, Ana R Rodríguez, Carlos Rinaldi, Madeline Torres-LugoDepartment of Chemical Engineering, University of Puerto Rico, Mayagüez 00681, Puerto RicoAbstract: Colloidal suspensions of iron oxide magnetic nanoparticles are known to dissipate energy when exposed to an oscillating magnetic field. Such energy dissipation can be employed to locally raise temperature i...

  4. Metabolic Profiling of Dividing Cells in Live Rodent Brain by Proton Magnetic Resonance Spectroscopy (1HMRS) and LCModel Analysis

    Park, June-Hee; Lee, Hedok; Makaryus, Rany;

    2014-01-01

    RATIONALE: Dividing cells can be detected in the live brain by positron emission tomography or optical imaging. Here we apply proton magnetic resonance spectroscopy (1HMRS) and a widely used spectral fitting algorithm to characterize the effect of increased neurogenesis after electroconvulsive...... shock in the live rodent brain via spectral signatures representing mobile lipids resonating at ∼1.30 ppm. In addition, we also apply the same 1HMRS methodology to metabolically profile glioblastomas with actively dividing cells growing in RCAS-PDGF mice. METHODS: 1HMRS metabolic profiles were acquired...... on a 9.4T MRI instrument in combination with LCModel spectral analysis of: 1) rat brains before and after ECS or sham treatments and 2) RCAS-PDGF mice with glioblastomas and wild-type controls. Quantified 1HMRS data were compared to post-mortem histology. RESULTS: Dividing cells in the rat...

  5. Propagation of localized structures in relativistic magnetized electron-positron plasmas using particle-in-cell simulations

    We use a particle-in-cell simulation to study the propagation of localized structures in a magnetized electron-positron plasma with relativistic finite temperature. We use as initial condition for the simulation an envelope soliton solution of the nonlinear Schrödinger equation, derived from the relativistic two fluid equations in the strongly magnetized limit. This envelope soliton turns out not to be a stable solution for the simulation and splits in two localized structures propagating in opposite directions. However, these two localized structures exhibit a soliton-like behavior, as they keep their profile after they collide with each other due to the periodic boundary conditions. We also observe the formation of localized structures in the evolution of a spatially uniform circularly polarized Alfvén wave. In both cases, the localized structures propagate with an amplitude independent velocity

  6. Full-power test of a string of magnets comprising a half-cell of the Superconducting Super Collider

    Burgett, W.; Christianson, M.; Coombes, R. [and others

    1992-10-01

    In this paper we describe the full-powered operation of a string of industrially-fabricated magnets comprising a half-cell of the Superconducting Super Collider (SSC). The completion of these tests marks the first successful operation of a major SSC subsystem. The five 15-m long dipole magnets in the string had an aperture of 50 mm and the single 5-m long quadrupole aperture was 40 mm. Power and cryogenic connections were made to the string through spool pieces that are prototypes for SSC operations. The string was cooled to cryogenic temperatures in early July, 1992, and power tests were performed at progressively higher currents up to the nominal SSC operating point above 6500 amperes achieved in mid-August. In this paper we report on the electrical and cryogenic performance of the string components and the quench protection system during these initial tests.

  7. Full-power test of a string of magnets comprising a half-cell of the Superconducting Super Collider

    In this paper we describe the full-powered operation of a string of industrially-fabricated magnets comprising a half-cell of the Superconducting Super Collider (SSC). The completion of these tests marks the first successful operation of a major SSC subsystem. The five 15-m long dipole magnets in the string had an aperture of 50 mm and the single 5-m long quadrupole aperture was 40 mm. Power and cryogenic connections were made to the string through spool pieces that are prototypes for SSC operations. The string was cooled to cryogenic temperatures in early July, 1992, and power tests were performed at progressively higher currents up to the nominal SSC operating point above 6500 amperes achieved in mid-August. In this paper we report on the electrical and cryogenic performance of the string components and the quench protection system during these initial tests

  8. Propagation of localized structures in relativistic magnetized electron-positron plasmas using particle-in-cell simulations

    López, Rodrigo A. [Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Concepción, Concepción 4070386 (Chile); Muñoz, Víctor [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Viñas, Adolfo F. [Geospace Physics Laboratory, Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771 (United States); Valdivia, Juan A. [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Centro para el Desarrollo de la Nanociencia y la Nanotecnología (CEDENNA), Santiago 9170124 (Chile)

    2015-09-15

    We use a particle-in-cell simulation to study the propagation of localized structures in a magnetized electron-positron plasma with relativistic finite temperature. We use as initial condition for the simulation an envelope soliton solution of the nonlinear Schrödinger equation, derived from the relativistic two fluid equations in the strongly magnetized limit. This envelope soliton turns out not to be a stable solution for the simulation and splits in two localized structures propagating in opposite directions. However, these two localized structures exhibit a soliton-like behavior, as they keep their profile after they collide with each other due to the periodic boundary conditions. We also observe the formation of localized structures in the evolution of a spatially uniform circularly polarized Alfvén wave. In both cases, the localized structures propagate with an amplitude independent velocity.

  9. Osteogenic differentiation of MC3T3-E1 cells on poly(L-lactide)/Fe3O4 nanofibers with static magnetic field exposure

    Proliferation and differentiation of bone-related cells are modulated by many factors such as scaffold design, growth factor, dynamic culture system, and physical simulation. Nanofibrous structure and moderate-intensity (1 mT–1 T) static magnetic field (SMF) have been identified as capable of stimulating proliferation and differentiation of osteoblasts. Herein, magnetic nanofibers were prepared by electrospinning mixture solutions of poly(L-lactide) (PLLA) and ferromagnetic Fe3O4 nanoparticles (NPs). The PLLA/Fe3O4 composite nanofibers demonstrated homogeneous dispersion of Fe3O4 NPs, and their magnetism depended on the contents of Fe3O4 NPs. SMF of 100 mT was applied in the culture of MC3T3-E1 osteoblasts on pure PLLA and PLLA/Fe3O4 composite nanofibers for the purpose of studying the effect of SMF on osteogenic differentiation of osteoblastic cells on magnetic nanofibrous scaffolds. On non-magnetic PLLA nanofibers, the application of external SMF could enhance the proliferation and osteogenic differentiation of MC3T3-E1 cells. In comparison with pure PLLA nanofibers, the incorporation of Fe3O4 NPs could also promote the proliferation and osteogenic differentiation of MC3T3-E1 cells in the absence or presence of external SMF. The marriage of magnetic nanofibers and external SMF was found most effective in accelerating every aspect of biological behaviors of MC3T3-E1 osteoblasts. The findings demonstrated that the magnetic feature of substrate and microenvironment were applicable ways in regulating osteogenesis in bone tissue engineering. - Highlights: • Magnetic nanofibers containing well-dispersed Fe3O4 nanoparticles were produced. • Static magnetic field (SMF) was applied to perform the culture of osteoblasts. • Osteogenic differentiation was enhanced on magnetic substrate with exposure to SMF

  10. Clear cell chondrosarcoma: radiographic, computed tomographic, and magnetic resonance findings in 34 patients with pathologic correlation

    Collins, Mark S.; Koyama, Takashi; Swee, Ronald G.; Inwards, Carrie Y. [Department of Radiology, Mayo Clinic, 200 First Street SW, MN 55905, Rochester (United States)

    2003-12-01

    To describe the radiographic features of clear cell chondrosarcoma (CCCS), including the computed tomographic (CT) and magnetic resonance (MR) findings, and to correlate them with the histopathologic findings. A retrospective review was carried out of 72 patients with histopathologically confirmed CCCS. Imaging studies were available for 34 patients: conventional radiographs (n=28), CT scans (n=14), and MR images (n=15). Radiographic studies were reviewed by three radiologists who rendered a consensus opinion; the studies were correlated with the histopathologic findings. Of the 34 patients with imaging studies, 30 were male and 4 were female (mean age 38.6 years; range 11-74 years). Twenty-two lesions were in long bones (15, proximal femur; 1, distal femur; 1, proximal tibia; 5, proximal humerus) and 11 were in flat bones (5, vertebra; 4, rib; 1, scapula; 1, innominate). One lesion occurred in the tarsal navicular bone. Typically, long bone lesions were located in the epimetaphysis (19/22) and were lucent with a well-defined sclerotic margin and no cortical destruction or periosteal new bone formation. More than one-third of the long bone lesions contained matrix mineralization with a characteristic chondroid appearance. Pathologic fractures were present in six long bone lesions (4, humerus; 2, femur). Lesions in the proximal humerus were more likely to have indistinct margins (4/5) and extend into the diaphysis. Flat bone lesions were typically lytic and expansile and occasionally demonstrated areas of cortical disruption. Typically, matrix mineralization, when present, was amorphous. MR imaging, when available, was superior to conventional radiographs for demonstrating the intramedullary extent of a lesion as well as soft tissue extension. CT images better delineated the presence of cortical destruction and the character of matrix mineralization patterns. CCCS lesions were typically low signal intensity on T1-weighted images and moderately or significantly

  11. Clear cell chondrosarcoma: radiographic, computed tomographic, and magnetic resonance findings in 34 patients with pathologic correlation

    To describe the radiographic features of clear cell chondrosarcoma (CCCS), including the computed tomographic (CT) and magnetic resonance (MR) findings, and to correlate them with the histopathologic findings. A retrospective review was carried out of 72 patients with histopathologically confirmed CCCS. Imaging studies were available for 34 patients: conventional radiographs (n=28), CT scans (n=14), and MR images (n=15). Radiographic studies were reviewed by three radiologists who rendered a consensus opinion; the studies were correlated with the histopathologic findings. Of the 34 patients with imaging studies, 30 were male and 4 were female (mean age 38.6 years; range 11-74 years). Twenty-two lesions were in long bones (15, proximal femur; 1, distal femur; 1, proximal tibia; 5, proximal humerus) and 11 were in flat bones (5, vertebra; 4, rib; 1, scapula; 1, innominate). One lesion occurred in the tarsal navicular bone. Typically, long bone lesions were located in the epimetaphysis (19/22) and were lucent with a well-defined sclerotic margin and no cortical destruction or periosteal new bone formation. More than one-third of the long bone lesions contained matrix mineralization with a characteristic chondroid appearance. Pathologic fractures were present in six long bone lesions (4, humerus; 2, femur). Lesions in the proximal humerus were more likely to have indistinct margins (4/5) and extend into the diaphysis. Flat bone lesions were typically lytic and expansile and occasionally demonstrated areas of cortical disruption. Typically, matrix mineralization, when present, was amorphous. MR imaging, when available, was superior to conventional radiographs for demonstrating the intramedullary extent of a lesion as well as soft tissue extension. CT images better delineated the presence of cortical destruction and the character of matrix mineralization patterns. CCCS lesions were typically low signal intensity on T1-weighted images and moderately or significantly

  12. Magnetic Resonance Findings of Primary Central Nervous System T-Cell Lymphoma in Immunocompetent Patients

    Kim, E.Y.; Kim, S.S. [Samsung Medical Center, Sungkyunkwan Univ. School of Medicine, Seoul (Korea, Republic of). Dept. of Radiology

    2005-04-01

    Purpose: To describe the MR findings of primary central nervous system T-cell lymphoma (T-PCNSL) in immunocompetent patients. Material and Methods: Seven patients with pathologically proven T-PCNSL were included in our study. The number, location, shape, enhancement pattern, and signal intensity of the tumors were determined. Diffusion-weighted images (DWI) and perfusion-weighted images (PWI) were obtained in four and two patients, respectively. Apparent diffusion coefficients (ADCs) were generated, and regions of interest were defined in each lesion. Results: Four patients with T-PCNSL had a single mass, while the others had multiple lesions (four, three, and two lesions, respectively). All seven cases of T-PCNSL had a supratentorial location: 12 in the subcortical area and 1 in the thalamus. No leptomeningeal involvement was noted. All tumors showed iso- to low T1 and iso- to slightly high T2 signal intensity to the adjacent gray matter. Rim enhancement was seen in 5 of the 7 patients (71.4%), while heterogeneous and homogeneous enhancement was seen in each of two. On DWI and ADC maps, the enhancing lesions showed slight hyperintensity in three patients (mean ADC ratio, 0.92{+-}0.06) and iso-intensity in the other (ADC ratio, 1.02{+-}0.05). Cystic areas consistent with necrosis were noted in three patients. High-signal intensity area in the cortex was noted on T1-weighted images in three patients, suggesting hemorrhage. In two patients, the same signal intensity area was noted within the mass. The two masses on the relative cerebral blood volume (rCBV) map demonstrated either similar or slightly higher signal intensity than that of the contralateral white matter. The rCBV ratios of these two masses were 1.27{+-}0.16 and 1.35{+-}0.2, respectively. Conclusion: T-PCNSLs show a predilection for a subcortical location, a relatively high incidence of cortical or intratumoral hemorrhage, rim enhancement, or cystic areas consistent with necrosis on magnetic resonance

  13. Cytotoxicity of magnetic nanoparticles derived from green chemistry against human cells

    Hanumandla, Pranitha

    The core-shelled Fe3O4 magnetic nanoparticles (MNPs) have been extensively investigated by the researchers due to their diversified applications. Recently, the study on the toxicity of nanomaterials has been drawn increasing attention to reduce or mitigate the environmental hazards and health risk. The objectives of this thesis are three fold: 1) prepare series functionalized Fe3O4 MNPs and optimize the synthesis variables of; 2) characterize their nanostructures using the state-of-the-art instrumental techniques; and 3) evaluate their cytotoxicity by measurement of nitrogen monoxide (NO) release, reactive oxygen species (ROS) and single oxygen species (SOS) generation. In order to prepare the crystalline Fe3O4 MNPs, a cost-effective and user-friendly wet chemistry (Sol-Gel) method was used. Two Indian medicinal plants were extracted to derive the active chemicals, which were used to functionalize the Fe3O 4 MNPs. The results indicated that the Fe3O4 MNPs were well-indexed with the standard inverse spinel structure (PDF 65-3107, a=8.3905A, α = 90°). The particle's sizes varied from 6-10 nm with the Fe3O 4 MNPs acting as cores and medicinal extracts as shell. The active chemical components extracted from two Hygrophila auriculata/ Chlorophytum borivilianum are fatty acid, Saponins, sterols, carbohydrates and amino acids, which are in agreement with the reported data. Toxicological evaluations of MNPs indicated that the Fe3O4 MNPs functionalized with Hygrophila auriculata/ Chlorophytum borivilianum extract prepared at room temperature were toxic to the cells when compared to the control, and act in a mechanism similar to the actions of hydrogen peroxide (H2O2). These functionalized MNPs, which were prepared at 100 ° C, displayed similar mechanism of action to the anticancer drug (SN-38). It was also found that the MNPs prepared at lower temperatures are less toxic and showed similar mechanism of action as the sodium nitrite (NaNO 2).

  14. Development and experimental basis of local subretinal technique of xenogenic’s injection stem cells labelled by magnetic perticles

    Yu. A. Belyy

    2014-10-01

    Full Text Available Purpose: is to develop a technique for local subretinal injection of xenogeneic stem cells labeled with magnetic particles and to prove experimentally its effectiveness.Material and methods: We used a line of stem cells HEK-293 GFP,labeled with magnetic particles. The study was made on 84 eyes of 42 chinchilla rabbits 6 months of age, the weight were from 2.5 to 3.5 kg. All right eyes were experimental (42 eyes and all left eyes (42 eyes were the control group. In the experimental group we used original complex of polymer elastic magnetic implant (PEMI with laser probe and fixed it to the sclera, then we made a median vitrectomy and injected HEK-293 GFP under the retina using a specially designed dispenser. In the control group PEMI was not fixed. We examined animals using biomicroscopy, ophthalmoscopy, ultrasound scanning, optical coherence tomography  OCT, computer tomography (CT, morphological study (cryohistological sections in 1, 3, 5, 7, 14 day and 1 month after surgery.Results: According the results of biomicroscopy in observation periods up to 3 days the vascular injection was visualized in the area operation. According the results of ophthalmoscopy and ultrasound scanning in 1 day the local retinal detachment was visualized in the area of local injection of the stem cells, which was not visualized in terms of further observations. CT helped us to confirm the local place of PEMI fixation. The morphological study results showed that cells were located in the subretinal space up to 14 days in the experimental group, and only up 3 days in the control group.Conclusion: The suggested surgical technique enables to control the injection of cells into the subretinal space, reduces the risk of tissue damage and exit cells in the vitreous space. The suggested methodology allows the fixing of the cellular material in the local place of the injection and enables to predict cells`s movement.

  15. Construction of Ang2-siRNA chitosan magnetic nanoparticles and the effect on Ang2 gene expression in human malignant melanoma cells

    LIU, ZHAO-LIANG; YOU, CAI-LIAN; WANG, BIAO; LIN, JIAN-HONG; HU, XUE-FENG; SHAN, XIU-YING; WANG, MEI-SHUI; ZHENG, HOU-BING; ZHANG, YAN-DING

    2016-01-01

    The aim of the present study was to construct angiopoietin-2 (Ang2)-small interfering (si)RNA chitosan magnetic nanoparticles and to observe the interference effects of the nanoparticles on the expression of the Ang2 gene in human malignant melanoma cells. Ang2-siRNA chitosan magnetic nanoparticles were constructed and transfected into human malignant melanoma cells in vitro. Red fluorescent protein expression was observed, and the transfection efficiency was analyzed. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to assess the inhibition efficiency of Ang2 gene expression. Ang2-siRNA chitosan magnetic nanoparticles were successfully constructed, and at a mass ratio of plasmid to magnetic chitosan nanoparticles of 1:100, the transfection efficiency into human malignant melanoma cells was the highest of the ratios assessed, reaching 61.17%. RT-qPCR analysis showed that the magnetic chitosan nanoparticles effectively inhibited Ang2 gene expression in cells, and the inhibition efficiency reached 59.56% (P<0.05). Ang2-siRNA chitosan magnetic nanoparticles were successfully constructed. The in vitro studies showed that the nanoparticles inhibited Ang2 gene expression in human malignant melanoma tumor cells, which laid the foundation and provided experimental evidence for additional future in vivo studies of intervention targeting malignant melanoma tumor growth in nude mice. PMID:27313729

  16. Application of magnetic field hyperthermia and superparamagnetic iron oxide nanoparticles to HIV-1-specific T-cell cytotoxicity

    Williams, James P; Southern, Paul; Lissina, Anya; Christian, Helen C; Sewell, Andrew K; Phillips, Rodney; Pankhurst, Quentin; Frater, John

    2013-01-01

    The latent HIV-1 reservoir remains the major barrier to HIV-1 eradication. Although successful at limiting HIV replication, highly active antiretroviral therapy is unable to cure HIV infection, thus novel therapeutic strategies are needed to eliminate the virus. Magnetic field hyperthermia (MFH) generates thermoablative cytotoxic temperatures in target-cell populations, and has delivered promising outcomes in animal models, as well as in several cancer clinical trials. MFH has been proposed as a strategy to improve the killing of HIV-infected cells and for targeting the HIV latent reservoirs. We wished to determine whether MFH could be used to enhance cytotoxic T-lymphocyte (CTL) targeting of HIV-infected cells in a proof-of-concept study. Here, for the first time, we apply MFH to an infectious disease (HIV-1) using the superparamagnetic iron oxide nanoparticle FeraSpin R. We attempt to improve the cytotoxic potential of T-cell receptor-transfected HIV-specific CTLs using thermotherapy, and assess superparamagnetic iron oxide nanoparticle toxicity, uptake, and effect on cell function using more sensitive methods than previously described. FeraSpin R exhibited only limited toxicity, demonstrated efficient uptake and cell-surface attachment, and only modestly impacted T-cell function. In contrast to the cancer models, insufficient MFH was generated to enhance CTL killing of HIV-infected cells. MFH remains an exciting new technology in the field of cancer therapeutics, which, as technology improves, may have significant potential to enhance CTL function and act as an adjunctive therapy in the eradication of latently infected HIV-positive cells. PMID:23901272

  17. Pd nanoparticles encapsulated in magnetic carbon nanocages: an efficient nanoenzyme for the selective detection and multicolor imaging of cancer cells

    Chen, Gaosong; Song, Jingjing; Zhang, Haoli; Jiang, Yuntian; Liu, Weisheng; Zhang, Wei; Wang, Baodui

    2015-08-01

    Rapid and simple molecular recognition based techniques for the identification of the subtypes of cancer cells are essential in molecular medicine. However, improving the sensitivity and accuracy of the early diagnosis of this disease remains a major challenge. Herein, we develop a novel approach for the in situ growth of palladium nanoparticles in magnetic carbon nanocages (PdNPs/MCNCs). The confined Pd NPs, which have excellent dispersion in magnetic carbon nanocages, show superior catalytic performance for the cleavage reaction of N-butyl-4-NHAlloc-1,8-naphthalimide (NNPH), thereby producing significant changes in both color (from colorless to jade-green) and fluorescence (from blue to green) through the ICT process. Based on the abovementioned results, a novel sensing platform utilizing the PdNPs/MCNC nanocatalyst as an artificial enzyme and NNPH as a fluorescent and color change reporter molecule for the multicolor imaging and colorimetric detection of cancer cells was developed. We envision that this nanomaterial can be used as a power tool for a wide range of potential applications in biotechnology and medicine.Rapid and simple molecular recognition based techniques for the identification of the subtypes of cancer cells are essential in molecular medicine. However, improving the sensitivity and accuracy of the early diagnosis of this disease remains a major challenge. Herein, we develop a novel approach for the in situ growth of palladium nanoparticles in magnetic carbon nanocages (PdNPs/MCNCs). The confined Pd NPs, which have excellent dispersion in magnetic carbon nanocages, show superior catalytic performance for the cleavage reaction of N-butyl-4-NHAlloc-1,8-naphthalimide (NNPH), thereby producing significant changes in both color (from colorless to jade-green) and fluorescence (from blue to green) through the ICT process. Based on the abovementioned results, a novel sensing platform utilizing the PdNPs/MCNC nanocatalyst as an artificial enzyme and NNPH

  18. Megalophallus as a sequela of priapism in sickle cell anemia: use of blood oxygen level-dependent magnetic resonance imaging.

    Kassim, A A; Umans, H; Nagel, R L; Fabry, M E

    2000-09-01

    Priapism is a common complication of sickle cell anemia. We report a little known sequela of priapism: painless megalophallus, with significant penile enlargement. The patient had had an intense episode of priapism 9 years previously and his penis remained enlarged. Blood oxygen level-dependent magnetic resonance imaging revealed enlarged, hypoxic corpora cavernosa. Megalophallus probably resulted from permanent loss of elasticity of the tunica albuginea due to severe engorgement during the episode of priapism. This sequela needs to be recognized by physicians because no intervention is necessary and sexual function seems to remain intact. PMID:10962334

  19. A Combined Chemical and Magneto-Mechanical Induction of Cancer Cell Death by the Use of Functionalized Magnetic Iron Nanowires

    Martinez Banderas, Aldo

    2016-04-01

    Cancer prevails as one of the most devastating diseases being at the top of death causes for adults despite continuous development and innovation in cancer therapy. Nanotechnology may be used to achieve therapeutic dosing, establish sustained-release drug profiles, and increase the half-life of drugs. In this context, magnetic nanowires (NWs) have shown a good biocompatibility and cellular internalization with a low cytotoxic effect. In this thesis, I induced cancer cell death by combining the chemotherapeutic effect of iron NWs functionalized with Doxorubicin (DOX) with mechanical disturbance under a low frequency alternating magnetic field. Two different agents, APTES and BSA, were separately used for coating NWs permitting further functionalization with DOX. Internalization was qualitatively and quantitatively assessed for both formulations by confocal reflection microscopy and inductively coupled plasma-mass spectrometry. From confocal reflection analysis, BSA formulations demonstrate to have a higher internalization degree and a broader distribution within the cells in comparison to APTES formulations. Both groups of functionalized NWs generated a comparable cytotoxic effect in MDA-MB-231 breast cancer cells in a DOX concentration-dependent manner, (~60% at the highest concentration tested) that was significantly different from the effect produced by the free DOX (~95% at the same concentration) and non-functionalized NWs formulations (~10% at the same NWs concentration). A synergistic cytotoxic effect is obtained when a low frequency magnetic field (1 mT, 10 Hz) is applied to cells treated with the two formulations that is again comparable (~70% at the highest concentration). Furthermore, the cytotoxic effect of both groups of coated NWs without the drug increased notoriously when the field is applied (~25% at the highest concentration tested). Here, a novel bimodal method for cancer cell destruction was developed by the conjugation of the magneto

  20. Supersonic Magnetic Upflows in Granular Cells Observed with Sunrise/IMaX

    Borrero, J M; Schlichenmaier, R; Solanki, S K; Bonet, J A; Iniesta, J C del Toro; Schmidt, W; Barthol, P; Gandorfer, A; Domingo, V; Knoelker, M

    2010-01-01

    Using the IMaX instrument on-board the Sunrise stratospheric balloon-telescope we have detected extremely shifted polarization signals around the Fe I 5250.217 {\\AA} spectral line within granules in the solar photosphere. We interpret the velocities associated with these events as corresponding to supersonic and magnetic upflows. In addition, they are also related to the appearance of opposite polarities and highly inclined magnetic fields. This suggests that they are produced by the reconnection of emerging magnetic loops through granular upflows. The events occupy an average area of 0.046 arcsec$^2$ and last for about 80 seconds, with larger events having longer lifetimes. These supersonic events occur at a rate of $1.3\\times10^{-5}$ occurrences per second per arcsec$^{2}$.

  1. Magneto-controllable capture and release of cancer cells by using a micropillar device decorated with graphite oxide-coated magnetic nanoparticles.

    Yu, Xiaolei; He, Rongxiang; Li, Shasha; Cai, Bo; Zhao, Libo; Liao, Lei; Liu, Wei; Zeng, Qian; Wang, Hao; Guo, Shi-Shang; Zhao, Xing-Zhong

    2013-11-25

    Aiming to highly efficient capture and analysis of circulating tumor cells, a micropillar device decorated with graphite oxide-coated magnetic nanoparticles is developed for magneto-controllable capture and release of cancer cells. Graphite oxide-coated, Fe3 O4 magnetic nanoparticles (MNPs) are synthesized by solution mixing and functionalized with a specific antibody, following by the immobilization of such modified MNPs on our designed micropillar device. For the proof-of-concept study, a HCT116 colorectal cancer cell line is employed to exam the capture efficiency. Under magnetic field manipulation, the high density packing of antibody-modified MNPs on the micropillars increases the local concentration of antibody, as well as the topographic interactions between cancer cells and micropillar surfaces. The flow rate and the micropillar geometry are optimized by studying their effects on capture efficiency. Then, a different number of HCT116 cells spiked in two kinds of cell suspension are investigated, yielding capture efficiency >70% in culture medium and >40% in blood sample, respectively. Moreover, the captured HCT116 cells are able to be released from the micropillars with a saturated efficiency of 92.9% upon the removal of applied magnetic field and it is found that 78% of the released cancer cells are viable, making them suitable for subsequent biological analysis. PMID:23650272

  2. 19F magnetic resonance imaging for stem/progenitor cell tracking with multiple unique perfluorocarbon nanobeacons.

    Partlow, Kathryn C; Chen, Junjie; Brant, Jason A; Neubauer, Anne M; Meyerrose, Todd E; Creer, Michael H; Nolta, Jan A; Caruthers, Shelton D; Lanza, Gregory M; Wickline, Samuel A

    2007-06-01

    MRI has been employed to elucidate the migratory behavior of stem/progenitor cells noninvasively in vivo with traditional proton (1H) imaging of iron oxide nanoparticle-labeled cells. Alternatively, we demonstrate that fluorine (19F) MRI of cells labeled with different types of liquid perfluorocarbon (PFC) nanoparticles produces unique and sensitive cell markers distinct from any tissue background signal. To define the utility for cell tracking, mononuclear cells harvested from human umbilical cord blood were grown under proendothelial conditions and labeled with nanoparticles composed of two distinct PFC cores (perfluorooctylbromide and perfluoro-15-crown-5 ether). The sensitivity for detecting and imaging labeled cells was defined on 11.7T (research) and 1.5T (clinical) scanners. Stem/progenitor cells (CD34+ CD133+ CD31+) readily internalized PFC nanoparticles without aid of adjunctive labeling techniques, and cells remained functional in vivo. PFC-labeled cells exhibited distinct 19F signals and were readily detected after both local and intravenous injection. PFC nanoparticles provide an unequivocal and unique signature for stem/progenitor cells, enable spatial cell localization with 19F MRI, and permit quantification and detection of multiple fluorine signatures via 19F MR spectroscopy. This method should facilitate longitudinal investigation of cellular events in vivo for multiple cell types simultaneously. PMID:17284484

  3. 19F magnetic resonance imaging for stem/progenitor cell tracking with multiple unique perfluorocarbon nanobeacons.

    Partlow KC; Chen J; Brant JA; Neubauer AM; Meyerrose TE; Creer MH; Nolta JA; Caruthers SD; Lanza GM; Wickline SA

    2007-06-01

    MRI has been employed to elucidate the migratory behavior of stem/progenitor cells noninvasively in vivo with traditional proton (1H) imaging of iron oxide nanoparticle-labeled cells. Alternatively, we demonstrate that fluorine (19F) MRI of cells labeled with different types of liquid perfluorocarbon (PFC) nanoparticles produces unique and sensitive cell markers distinct from any tissue background signal. To define the utility for cell tracking, mononuclear cells harvested from human umbilical cord blood were grown under proendothelial conditions and labeled with nanoparticles composed of two distinct PFC cores (perfluorooctylbromide and perfluoro-15-crown-5 ether). The sensitivity for detecting and imaging labeled cells was defined on 11.7T (research) and 1.5T (clinical) scanners. Stem/progenitor cells (CD34+ CD133+ CD31+) readily internalized PFC nanoparticles without aid of adjunctive labeling techniques, and cells remained functional in vivo. PFC-labeled cells exhibited distinct 19F signals and were readily detected after both local and intravenous injection. PFC nanoparticles provide an unequivocal and unique signature for stem/progenitor cells, enable spatial cell localization with 19F MRI, and permit quantification and detection of multiple fluorine signatures via 19F MR spectroscopy. This method should facilitate longitudinal investigation of cellular events in vivo for multiple cell types simultaneously.

  4. Planar Integrated Magnetics (PIM) Module in Hybrid Bidirectional DC-DC Converter for Fuel Cell Application

    Ouyang, Ziwei; Zhang, Zhe; Thomsen, Ole Cornelius;

    2011-01-01

    , hereby increasing the power density of converters. In this paper, a new planar integrated magnetics (PIM) module for a phase-shift plus duty cycle controlled hybrid bi-directional dc-dc converter is proposed, which assembles one boost inductor and two transformers into an E-I-E core geometry, reducing...... the number of parts, the total volume of converter, as well as the total core loss of the magnetic components. AC losses in the windings and leakage inductance of the transformers are kept low by interleaving the primary and secondary turns of the transformers. To verify the validity of the design...

  5. Magnetic reconnection during collisionless, stressed, X-point collapse using Particle-in-Cell simulation

    Tsiklauri, D.; HARUKI, T

    2007-01-01

    Two cases of weakly and strongly stressed X-point collapse were considered. Here descriptors weakly and strongly refer to 20 % and 124 % unidirectional spatial compression of the X-point, respectively. In the weakly stressed case, the reconnection rate, defined as the out-of-plane electric field in the X-point (the magnetic null) normalised by the product of external magnetic field and Alfv\\'en speeds, peaks at 0.11, with its average over 1.25 Alfv\\'en times being 0.04. Electron energy distri...

  6. Effect of different magnetic nanoparticle coatings on the efficiency of stem cell labeling

    Horák, Daniel; Babič, Michal; Jendelová, Pavla; Herynek, V.; Trchová, Miroslava; Mašínová, Katarína; Kapcalová, Miroslava; Syková, Eva; Hájek, M.

    2009-01-01

    Roč. 321, č. 10 (2009), s. 1539-1547. ISSN 0304-8853. [International Conference on Scientific and Clinical Applications of Magnetic Carriers /7./. Vancouver, 20.05.2008-24.05.2008] R&D Projects: GA AV ČR KAN201110651; GA AV ČR KAN200200651; GA ČR GA203/09/1242 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z50390512 Keywords : magnetic nanoparticles * maghemite * MRI Subject RIV: FR - Pharmacology ; Medidal Chemistry Impact factor: 1.204, year: 2009

  7. Aptamer-based isolation and subsequent imaging of mesenchymal stem cells in ischemic myocard by magnetic resonance imaging

    Schaefer, R.; Hermanutz-Klein, U.; Northoff, H. [Universitaetsklinikum Tuebingen (Germany). Inst. fuer Klinische und Experimentelle Transfusionsmedizin; Wiskirchen, J.; Kehlbach, R.; Pintaske, J. [Universitaetsklinikum Tuebingen (Germany). Abt. fuer Radiologische Diagnostik; Guo, K.; Neumann, B.; Voth, V.; Walker, T.; Scheule, A.M.; Greiner, T.O.; Ziemer, G.; Wendel, H.P. [Universitaetsklinikum Tuebingen (Germany). Abt. fuer Thorax-, Herz- und Gefaesschirurgie; Claussen, C.D. [Universitaetsklinikum Tuebingen (Germany). Radiologische Universitaetsklinik

    2007-10-15

    Purpose: Mesenchymal stem cells (MSC) seem to be a promising cell source for cellular cardiomyoplasty. We recently developed a new aptamer-based specific selection of MSC to provide ''ready to transplant'' cells directly after isolation. We evaluated MRI tracking of newly isolated and freshly transplanted MSC in the heart using one short ex vivo selection step combining specific aptamer-based isolation and labeling of the cells. Materials and Methods: Bone marrow (BM) was collected from healthy pigs. The animals were euthanized and the heart was placed in a perfusion model. During cold ischemia, immunomagnetic isolation of MSC from the BM by MSC-specific aptamers labeled with Dynabeads {sup registered} was performed within 2 h. For histological identification the cells were additionally stained with PKH26. Approx. 3 x 10{sup 6} of the freshly aptamer-isolated cells were injected into the ramus interventricularis anterior (RIVA) and 5 x 10{sup 5} cells were injected directly into myocardial tissue after damaging the respective area by freezing (cryo-scar). 3 x 10{sup 6} of the aptamer-isolated cells were kept for further characterization (FACS and differentiation assays). 20 h after cell transplantation, MRI of the heart using a clinical 3.0 Tesla whole body scanner (Magnetom Trio, Siemens, Germany) was performed followed by histological examinations. Results: The average yield of sorted cells from 120 ml BM was 7 x 10{sup 6} cells. The cells were cultured and showed MSC-like properties. MRI showed reproducible artifacts within the RIVA-perfusion area and the cryo-scar with surprisingly excellent quality. The histological examination of the biopsies showed PKH26-positive cells within the areas which were positive in the MRI in contrast to the control biopsies. Conclusion: Immunomagnetic separation of MSC by specific aptamers linked to magnetic particles is feasible, effective and combines a specific separation and labeling technique to a &apos

  8. Evaluation of the effect of static magnetic fields combined with human hepatocyte growth factor on human satellite cell cultures.

    Birk, Richard; Sommer, Ulrich; Faber, Anne; Aderhold, Christoph; Schulz, Johannes D; Hörmann, Karl; Goessler, Ulrich Reinhart; Stern-Straeter, Jens

    2014-06-01

    Tissue engineering is a promising research field, which aims to create new functional muscle tissue in vitro, by utilizing the myogenic differentiation potential of human stem cells. The objective of the present study was to determine the effect of static magnetic fields (SMF), combined with the use of the myogenic differentiation enhancing hepatocyte growth factor (HGF), on human satellite cell cultures, which are one of the preferred stem cell sources in skeletal muscle tissue engineering. We performed almarBlue® proliferation assays and semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) for the following myogenic markers: desmin (DES), myogenic factor 5 (MYF5), myogenic differentiation antigen 1 (MYOD1), myogenin (MYOG), myosin heavy chain (MYH) and α1 actin (ACTA1) to detect the effects on myogenic maturation. Additionally, immunohistochemical staining (ICC) and fusion index (FI) determination as independent markers of differentiation were performed on satellite cell cultures stimulated with HGF and HGF + SMF with an intensity of 80 mT. ICC verified the muscle phenotype at all time points. SMF enhanced the proliferation of satellite cell cultures treated with HGF. RT-PCR analysis, ICC and FI calculation revealed the effects of HGF/SMF on the investigated differentiation markers and stimulation with HGF and SMF verified the continuing maturation, however no significant increase in analysed markers could be detected when compared with control cultures treated with serum cessation. In conclusion, HGF or HGF + SMF stimulation of human satellite cell cultures did not lead to the desired enhancement of myogenic maturation of human satellite cell cultures compared with cell cultures stimulated with growth factor reduction. PMID:24682107

  9. Lucifer Yellow uptake by CHO cells exposed to magnetic and electric pulses

    Miklavčič, Damijan; Towhidi, Leila; Firoozabadi, S. M. P.; Mozdarani, Hossein

    2012-01-01

    Background The cell membrane acts as a barrier that hinders free entrance of most hydrophilic molecules into the cell. Due to numerous applications in medicine, biology and biotechnology, the introduction of impermeant molecules into biological cells has drawn considerable attention in the past years. One of the most famous methods in this field is electroporation, in which electric pulses with high intensity and short duration are applied to the cells. The aim of our study was to investigate...

  10. Magnetic nanoparticles for oligodendrocyte precursor cell transplantation therapies: progress and challenges

    Jenkins, SI; Yiu, HH; Rosseinsky, MJ; Chari, DM

    2014-01-01

    Oligodendrocyte precursor cells (OPCs) have shown high promise as a transplant population to promote regeneration in the central nervous system, specifically, for the production of myelin – the protective sheath around nerve fibers. While clinical trials for these cells have commenced in some areas, there are currently key barriers to the translation of neural cell therapies. These include the ability to (a) image transplant populations in vivo; (b) genetically engineer transplant cells to au...

  11. Particle-in-cell simulation study of the scaling of asymmetric magnetic reconnection with in-plane flow shear

    Doss, C. E.; Cassak, P. A.; Swisdak, M.

    2016-08-01

    We investigate magnetic reconnection in systems simultaneously containing asymmetric (anti-parallel) magnetic fields, asymmetric plasma densities and temperatures, and arbitrary in-plane bulk flow of plasma in the upstream regions. Such configurations are common in the high-latitudes of Earth's magnetopause and in tokamaks. We investigate the convection speed of the X-line, the scaling of the reconnection rate, and the condition for which the flow suppresses reconnection as a function of upstream flow speeds. We use two-dimensional particle-in-cell simulations to capture the mixing of plasma in the outflow regions better than is possible in fluid modeling. We perform simulations with asymmetric magnetic fields, simulations with asymmetric densities, and simulations with magnetopause-like parameters where both are asymmetric. For flow speeds below the predicted cutoff velocity, we find good scaling agreement with the theory presented in Doss et al. [J. Geophys. Res. 120, 7748 (2015)]. Applications to planetary magnetospheres, tokamaks, and the solar wind are discussed.

  12. Fast-ignition transport studies: Realistic electron source, integrated particle-in-cell and hydrodynamic modeling, imposed magnetic fields

    Transport modeling of idealized, cone-guided fast ignition targets indicates the severe challenge posed by fast-electron source divergence. The hybrid particle-in-cell (PIC) code Zuma is run in tandem with the radiation-hydrodynamics code Hydra to model fast-electron propagation, fuel heating, and thermonuclear burn. The fast electron source is based on a 3D explicit-PIC laser-plasma simulation with the PSC code. This shows a quasi two-temperature energy spectrum and a divergent angle spectrum (average velocity-space polar angle of 52°). Transport simulations with the PIC-based divergence do not ignite for >1 MJ of fast-electron energy, for a modest (70 μm) standoff distance from fast-electron injection to the dense fuel. However, artificially collimating the source gives an ignition energy of 132 kJ. To mitigate the divergence, we consider imposed axial magnetic fields. Uniform fields ∼50 MG are sufficient to recover the artificially collimated ignition energy. Experiments at the Omega laser facility have generated fields of this magnitude by imploding a capsule in seed fields of 50-100 kG. Such imploded fields will likely be more compressed in the transport region than in the laser absorption region. When fast electrons encounter increasing field strength, magnetic mirroring can reflect a substantial fraction of them and reduce coupling to the fuel. A hollow magnetic pipe, which peaks at a finite radius, is presented as one field configuration which circumvents mirroring.

  13. Integration of Magnetic Components in a Step-Up Converter for Fuel Cell

    Klimczak, Pawel; Munk-Nielsen, Stig

    2009-01-01

    converter is a critical part. The input voltage of the converter decreases while the output power increases. It creates challenges in design of the converter's magnetic components. Scope of this paper is integration of the dc inductor and the transformer on a single core. Such integration improve...

  14. Invert sugar formation with Saccharomyces cerevisiae cells encapsulated in magnetically responsive alginate microparticles

    Šafařík, Ivo; Maděrová, Zdeňka; Šafaříková, Miroslava

    2009-01-01

    Roč. 321, - (2009), s. 1478-1481. ISSN 0304-8853 R&D Projects: GA MPO 2A-1TP1/094; GA MŠk(CZ) OC 157 Institutional research plan: CEZ:AV0Z60870520 Keywords : magnetic alginate microbeads * Saccharomyces cerevisiae * invertase Subject RIV: EI - Biotechnology ; Bionics Impact factor: 1.204, year: 2009

  15. Targeting of peptide conjugated magnetic nanoparticles to urokinase plasminogen activator receptor (uPAR) expressing cells

    Hansen, Line; Unmack Larsen, Esben Kjær; Nielsen, Erik Holm;

    2013-01-01

    Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are currently being used as a magnetic resonance imaging (MRI) contrast agent in vivo, mainly by their passive accumulation in tissues of interest. However, a higher specificity can ideally be achieved when the nanoparticles are targeted...... patient management when combined with MRI and drug delivery....

  16. Pulsed electrically detected magnetic resonance study of spin relaxation and recombination in thin-film silicon solar cells

    Fehr, Matthias; Behrends, Jan; Schnegg, Alexander; Lips, Klaus; Rech, Bernd [Helmholtz-Zentrum Berlin, Silizium Photovoltaik, Berlin (Germany); Astakhov, Oleksander; Finger, Friedhelm [Forschungszentrum Juelich (Germany). IEF-5 Photovoltaik

    2009-07-01

    We have investigated the influence of paramagnetic states on electronic transport processes in thin-film pin solar cells with pulsed Electrically Detected Magnetic Resonance (pEDMR) at X-Band frequency and low temperature (10 K). The solar cells consist of an intrinsic microcrystalline absorber layer and amorphous or microcrystalline n/p contacting layers. In addition to the identification of the participating paramagnetic centres by their g-factors, pEDMR can be used to study the dynamics of the electronic processes in detail. We present measurements of modified EPR pulse sequences in order to identify the dominating relaxation mechanisms within correlated solid-state spin-pairs. By this technique a monitoring of the spin and charge motion is possible. In the outlook we present measurements of the electron spin echo envelope and critically discuss modulations in terms of dipolar coupling within the spin-pairs or hyperfine couplings to surrounding nuclei.

  17. Nuclear magnetic resonance studies of biological systems: Applications to liver preservation and metabolism in cultured pituitary tumor cells

    This study centers on applications of both 31P and 13C nuclear magnetic resonance spectroscopy to two different biological systems. The first application utilizes 31P NMR to study mobile phospholipids in the MMQ cell line, a pituitary tumor cell line. These measurements characterize membrane phospholipids thought to be part of a RNA-proteolipid complex unique to cellular transformation. The second application utilizes both 31P and 13C spectroscopy to study liver preservation and transplantation an a rat model. In this work, several questions were addressed: (1) to what extent do successful preservation solutions slow ATP breakdown? (2) can clinically successful preservation conditions ameliorate total nucleotide breakdown? (3) to what extent is energy reconstitution following cold storage correlated with transport success? and (4) can any spectroscopic parameter be used as a diagnostic indicator of tissue viability?

  18. Repeated exposure of the developing rat brain to magnetic resonance imaging did not affect neurogenesis, cell death or memory function

    Zhu, Changlian [Center for Brain Repair and Rehabilitation, University of Gothenburg (Sweden); Department of Pediatrics, The Third Affiliated Hospital, Zhengzhou University (China); Gao, Jianfeng [Center for Brain Repair and Rehabilitation, University of Gothenburg (Sweden); Department of Pediatrics, The Third Affiliated Hospital, Zhengzhou University (China); Department of Physiology, Henan Traditional Medical University (China); Li, Qian; Huang, Zhiheng; Zhang, Yu; Li, Hongfu [Center for Brain Repair and Rehabilitation, University of Gothenburg (Sweden); Department of Pediatrics, The Third Affiliated Hospital, Zhengzhou University (China); Kuhn, Hans-Georg [Center for Brain Repair and Rehabilitation, University of Gothenburg (Sweden); Blomgren, Klas, E-mail: klas.blomgren@neuro.gu.se [Center for Brain Repair and Rehabilitation, University of Gothenburg (Sweden); Department of Pediatric Oncology, The Queen Silvia Children' s Hospital, Gothenburg (Sweden)

    2011-01-07

    Research highlights: {yields} The effect of MRI on the developing brain is a matter of debate. {yields} Repeated exposure to MRI did not affect neurogenesis. {yields} Memory function was not affected by repeated MRI during development. {yields} Neither late gestation nor young postnatal brains were affected by MRI. {yields} Repeated MRI did not cause cell death in the neurogenic region of the hippocampus. -- Abstract: The effect of magnetic fields on the brain is a matter of debate. The objective of this study was to investigate whether repeated exposure to strong magnetic fields, such as during magnetic resonance imaging (MRI), could elicit changes in the developing rat brain. Embryonic day 15 (E15) and postnatal day 14 (P14) rats were exposed to MRI using a 7.05 T MR system. The animals were anesthetized and exposed for 35 min per day for 4 successive days. Control animals were anesthetized but no MRI was performed. Body temperature was maintained at 37 {sup o}C. BrdU was injected after each session (50 mg/kg). One month later, cell proliferation, neurogenesis and astrogenesis in the dentate gyrus were evaluated, revealing no effects of MRI, neither in the E15, nor in the P14 group. DNA damage in the dentate gyrus in the P14 group was evaluated on P18, 1 day after the last session, using TUNEL staining. There was no difference in the number of TUNEL-positive cells after MRI compared with controls, neither in mature neurons, nor in newborn progenitors (BrdU/TUNEL double-labeled cells). Novel object recognition was performed to assess memory function 1 month after MRI. There was no difference in the recognition index observed after MRI compared with the control rats, neither for the E15, nor for the P14 group. In conclusion, repeated exposure to MRI did not appear to affect neurogenesis, cell death or memory function in rats, neither in late gestation (E15-E18) nor in young postnatal (P14-P17) rats.

  19. Repeated exposure of the developing rat brain to magnetic resonance imaging did not affect neurogenesis, cell death or memory function

    Research highlights: → The effect of MRI on the developing brain is a matter of debate. → Repeated exposure to MRI did not affect neurogenesis. → Memory function was not affected by repeated MRI during development. → Neither late gestation nor young postnatal brains were affected by MRI. → Repeated MRI did not cause cell death in the neurogenic region of the hippocampus. -- Abstract: The effect of magnetic fields on the brain is a matter of debate. The objective of this study was to investigate whether repeated exposure to strong magnetic fields, such as during magnetic resonance imaging (MRI), could elicit changes in the developing rat brain. Embryonic day 15 (E15) and postnatal day 14 (P14) rats were exposed to MRI using a 7.05 T MR system. The animals were anesthetized and exposed for 35 min per day for 4 successive days. Control animals were anesthetized but no MRI was performed. Body temperature was maintained at 37 oC. BrdU was injected after each session (50 mg/kg). One month later, cell proliferation, neurogenesis and astrogenesis in the dentate gyrus were evaluated, revealing no effects of MRI, neither in the E15, nor in the P14 group. DNA damage in the dentate gyrus in the P14 group was evaluated on P18, 1 day after the last session, using TUNEL staining. There was no difference in the number of TUNEL-positive cells after MRI compared with controls, neither in mature neurons, nor in newborn progenitors (BrdU/TUNEL double-labeled cells). Novel object recognition was performed to assess memory function 1 month after MRI. There was no difference in the recognition index observed after MRI compared with the control rats, neither for the E15, nor for the P14 group. In conclusion, repeated exposure to MRI did not appear to affect neurogenesis, cell death or memory function in rats, neither in late gestation (E15-E18) nor in young postnatal (P14-P17) rats.

  20. Pd nanoparticles encapsulated in magnetic carbon nanocages: an efficient nanoenzyme for the selective detection and multicolor imaging of cancer cells.

    Chen, Gaosong; Song, Jingjing; Zhang, Haoli; Jiang, Yuntian; Liu, Weisheng; Zhang, Wei; Wang, Baodui

    2015-09-14

    Rapid and simple molecular recognition based techniques for the identification of the subtypes of cancer cells are essential in molecular medicine. However, improving the sensitivity and accuracy of the early diagnosis of this disease remains a major challenge. Herein, we develop a novel approach for the in situ growth of palladium nanoparticles in magnetic carbon nanocages (PdNPs/MCNCs). The confined Pd NPs, which have excellent dispersion in magnetic carbon nanocages, show superior catalytic performance for the cleavage reaction of N-butyl-4-NHAlloc-1,8-naphthalimide (NNPH), thereby producing significant changes in both color (from colorless to jade-green) and fluorescence (from blue to green) through the ICT process. Based on the abovementioned results, a novel sensing platform utilizing the PdNPs/MCNC nanocatalyst as an artificial enzyme and NNPH as a fluorescent and color change reporter molecule for the multicolor imaging and colorimetric detection of cancer cells was developed. We envision that this nanomaterial can be used as a power tool for a wide range of potential applications in biotechnology and medicine. PMID:26248481

  1. Optimized labeling of bone marrow mesenchymal cells with superparamagnetic iron oxide nanoparticles and in vivo visualization by magnetic resonance imaging

    Spray David C

    2011-02-01

    Full Text Available Abstract Background Stem cell therapy has emerged as a promising addition to traditional treatments for a number of diseases. However, harnessing the therapeutic potential of stem cells requires an understanding of their fate in vivo. Non-invasive cell tracking can provide knowledge about mechanisms responsible for functional improvement of host tissue. Superparamagnetic iron oxide nanoparticles (SPIONs have been used to label and visualize various cell types with magnetic resonance imaging (MRI. In this study we performed experiments designed to investigate the biological properties, including proliferation, viability and differentiation capacity of mesenchymal cells (MSCs labeled with clinically approved SPIONs. Results Rat and mouse MSCs were isolated, cultured, and incubated with dextran-covered SPIONs (ferumoxide alone or with poly-L-lysine (PLL or protamine chlorhydrate for 4 or 24 hrs. Labeling efficiency was evaluated by dextran immunocytochemistry and MRI. Cell proliferation and viability were evaluated in vitro with Ki67 immunocytochemistry and live/dead assays. Ferumoxide-labeled MSCs could be induced to differentiate to adipocytes, osteocytes and chondrocytes. We analyzed ferumoxide retention in MSCs with or without mitomycin C pretreatment. Approximately 95% MSCs were labeled when incubated with ferumoxide for 4 or 24 hrs in the presence of PLL or protamine, whereas labeling of MSCs incubated with ferumoxide alone was poor. Proliferative capacity was maintained in MSCs incubated with ferumoxide and PLL for 4 hrs, however, after 24 hrs it was reduced. MSCs incubated with ferumoxide and protamine were efficiently visualized by MRI; they maintained proliferation and viability for up to 7 days and remained competent to differentiate. After 21 days MSCs pretreated with mitomycin C still showed a large number of ferumoxide-labeled cells. Conclusions The efficient and long lasting uptake and retention of SPIONs by MSCs using a protocol

  2. Isolation, cultivation and identification of brain glioma stem cells by magnetic bead sorting

    Xiuping Zhou; Chao Zheng; Qiong Shi; Xiang Li; Zhigang Shen; Rutong Yu

    2012-01-01

    This study describes a detailed process for obtaining brain glioma stem cells from freshly dissected human brain glioma samples using an immunomagnetic bead technique combined with serum-free media pressure screening. Furthermore, the proliferation, differentiation and self-renewal biological features of brain glioma stem cells were identified. Results showed that a small number of CD133 positive tumor cells isolated from brain glioma samples survived as a cell suspension in serum-free media and proliferated. Subcultured CD133 positive cells maintained a potent self-renewal and proliferative ability, and expressed the stem cell-specific markers CD133 and nestin. After incubation with fetal bovine serum, the number of glial fibrillary acidic protein and microtubule associated protein 2 positive cells increased significantly, indicating that the cultured brain glioma stem cells can differentiate into astrocytes and neurons. Western blot analysis showed that tumor suppressor phosphatase and tensin homolog was highly expressed in tumor spheres compared with the differentiated tumor cells. These experimental findings indicate that the immunomagnetic beads technique is a useful method to obtain brain glioma stem cells from human brain tumors.

  3. Magnetic nanotubes

    Matsui, Hiroshi; Matsunaga, Tadashi

    2010-11-16

    A magnetic nanotube includes bacterial magnetic nanocrystals contacted onto a nanotube which absorbs the nanocrystals. The nanocrystals are contacted on at least one surface of the nanotube. A method of fabricating a magnetic nanotube includes synthesizing the bacterial magnetic nanocrystals, which have an outer layer of proteins. A nanotube provided is capable of absorbing the nanocrystals and contacting the nanotube with the nanocrystals. The nanotube is preferably a peptide bolaamphiphile. A nanotube solution and a nanocrystal solution including a buffer and a concentration of nanocrystals are mixed. The concentration of nanocrystals is optimized, resulting in a nanocrystal to nanotube ratio for which bacterial magnetic nanocrystals are immobilized on at least one surface of the nanotubes. The ratio controls whether the nanocrystals bind only to the interior or to the exterior surfaces of the nanotubes. Uses include cell manipulation and separation, biological assay, enzyme recovery, and biosensors.

  4. Investigations on the mechanisms change and growth of mammary gland tumor cells under the influence of antiestrogenic drugs and low-frequency magnetic fields

    In the present project we investigated the molecular mechanism of the decreased antiproliferative effect of the antiestrogenic drug Tamoxifen and the pineal gland hormone Melatonin on breast cancer cells in the presence of low-frequency electromagnetic fields. New unique incubators were developed for the exposure of the cells to controlled, highly homogenous magnetic fields. MCF-7 p40 cells exposed to 1.2 μT expressed 20 genes more than two times stronger than control cells, MCF-7p181 cells 61 genes. 16 genes were expressed weaker in MCF-7p40 cells, 41 genes in MCF-7p181. The increased expression of the particularly interesting coactivators, AIB1 and SRC-1, and of urokinase plasminogen activator and plasminogen-activator inhibitor was confirmed using RT-PCR and Western blot. The corepressors, N-Cor and SMRT, and various metastasis-suppressor genes were expressed lower in the exposed cells. Investigations of signal transduction revealed only MAP-kinase Erk1 being more strongly activated after one hour exposure to the magnetic field, while stress-activated MAP-kinases, junK and p38, were not activated by the magnetic field or even slightly deactivated. Experiments on Melatonin action in the magnetic field showed that expression of the two Melatonin receptors, MT1 and RZRα, was only marginally altered at 1,2 μT. Of the target genes of Melatonin expression of tumorsuppressors p53 and p21waf was decreased in the magnetic field whereas the decrease in expression of BRCA1 and c-myc by Melatonin was less strong in the magnetic field.

  5. A Study of the Conditions of Maximum Filtration Efficiency for a HGMF-Axial Magnetic Filter Cell With Bounded Flow Field

    Badescu, V.; Murariu, V.; Rotariu, O.; Rezlescu, N.

    1996-01-01

    The theory of magnetic particles′ capture on a HGMF-axial magnetic filter cell with bounded flow field is presented. The equations of particle motion for both potential and laminar flow are obtained. By analytical solving of these equations, the trajectories of particles are established. The flow velocity of the fluid suspension for the case of potential flow is set equal with the velocity averaged across the tube section for the laminar flow. Thus, it is possible to make a comparison between...

  6. Anti-EpCAM-immobilized albumin-coated monodisperse magnetic poly(glycidyl methacrylate) microspheres for detection of circulating tumor cells

    Horák, Daniel; Svobodová, Z.; Autebert, J.; Bílková, Z.; Viovy, J.-L.

    Vancouver : Faculty of Pharmaceutical Sciences, The University of British Columbia, 2012. Talk 75. [International Conference on the Scientific and Clinical Applications of Magnetic Carriers /9./. 22.05.2012-26.05.2012, Minneapolis] R&D Projects: GA MŠk 7E09109 EU Projects: European Commission(XE) 228980 - CAMINEMS Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : magnetic * microspheres * circulating tumor cells Subject RIV: CD - Macromolecular Chemistry

  7. Magnetic Nanoparticles for Targeting and Imaging of Stem Cells in Myocardial Infarction

    Michelle R. Santoso

    2016-01-01

    Full Text Available Stem cell therapy has broad applications in regenerative medicine and increasingly within cardiovascular disease. Stem cells have emerged as a leading therapeutic option for many diseases and have broad applications in regenerative medicine. Injuries to the heart are often permanent due to the limited proliferation and self-healing capability of cardiomyocytes; as such, stem cell therapy has become increasingly important in the treatment of cardiovascular diseases. Despite extensive efforts to optimize cardiac stem cell therapy, challenges remain in the delivery and monitoring of cells injected into the myocardium. Other fields have successively used nanoscience and nanotechnology for a multitude of biomedical applications, including drug delivery, targeted imaging, hyperthermia, and tissue repair. In particular, superparamagnetic iron oxide nanoparticles (SPIONs have been widely employed for molecular and cellular imaging. In this mini-review, we focus on the application of superparamagnetic iron oxide nanoparticles in targeting and monitoring of stem cells for the treatment of myocardial infarctions.

  8. Magnetic Nanoparticles for Targeting and Imaging of Stem Cells in Myocardial Infarction

    Santoso, Michelle R.; Yang, Phillip C.

    2016-01-01

    Stem cell therapy has broad applications in regenerative medicine and increasingly within cardiovascular disease. Stem cells have emerged as a leading therapeutic option for many diseases and have broad applications in regenerative medicine. Injuries to the heart are often permanent due to the limited proliferation and self-healing capability of cardiomyocytes; as such, stem cell therapy has become increasingly important in the treatment of cardiovascular diseases. Despite extensive efforts t...

  9. Generation of Helical and Axial Magnetic Fields by the Relativistic Laser Pulses in Under-dense Plasma: Three-Dimensional Particle-in-Cell Simulation

    郑春阳; 朱少平; 贺贤土

    2002-01-01

    The quasi-static magnetic fields created in the interaction of relativistic laser pulses with under-dense plasmashave been investigated by three-dimensional particle-in-cell simulation. The relativistic ponderomotive force candrive an intense electron current in the laser propagation direction, which is responsible for the generation ofa helical magnetic field. The axial magnetic field results from a difference beat of wave-wave, which drives asolenoidal current. In particular, the physical significance of the kinetic model for the generation of the axialmagnetic field is discussed.

  10. High Antimicrobial Activity and Low Human Cell Cytotoxicity of Core-Shell Magnetic Nanoparticles Functionalized with an Antimicrobial Peptide.

    Maleki, Hajar; Rai, Akhilesh; Pinto, Sandra; Evangelista, Marta; Cardoso, Renato M S; Paulo, Cristiana; Carvalheiro, Tiago; Paiva, Artur; Imani, Mohammad; Simchi, Abdolreza; Durães, Luísa; Portugal, António; Ferreira, Lino

    2016-05-11

    Superparamagnetic iron oxide nanoparticles (SPIONs) functionalized with antimicrobial agents are promising infection-targeted therapeutic platforms when coupled with external magnetic stimuli. These antimicrobial nanoparticles (NPs) may offer advantages in fighting intracellular pathogens as well as biomaterial-associated infections. This requires the development of NPs with high antimicrobial activity without interfering with the biology of mammalian cells. Here, we report the preparation of biocompatible antimicrobial SPION@gold core-shell NPs based on covalent immobilization of the antimicrobial peptide (AMP) cecropin melittin (CM) (the conjugate is named AMP-NP). The minimal inhibitory concentration (MIC) of the AMP-NP for Escherichia coli was 0.4 μg/mL, 10-times lower than the MIC of soluble CM. The antimicrobial activity of CM depends on the length of the spacer between the CM and the NP. AMP-NPs are taken up by endothelial (between 60 and 170 pg of NPs per cell) and macrophage (between 18 and 36 pg of NPs per cell) cells and accumulate preferentially in endolysosomes. These NPs have no significant cytotoxic and pro-inflammatory activities for concentrations up to 200 μg/mL (at least 100 times higher than the MIC of soluble CM). Our results in membrane models suggest that the selectivity of AMP-NPs for bacteria and not eukaryotic membranes is due to their membrane compositions. The AMP-NPs developed here open new opportunities for infection-site targeting. PMID:27074633

  11. Influence of static magnetic fields combined with human insulin-like growth factor 1 on human satellite cell cultures.

    Birk, Richard; Sommer, J Ulrich; Haas, Dominik; Faber, Anne; Aderhold, Christoph; Schultz, Johannes D; Hoermann, Karl; Stern-Straeter, Jens

    2014-01-01

    Tissue engineering represents a promising research field, targeting the creation of new functional muscle tissue in vitro. The aim of the present study was to show the influence of static magnetic fields (SMF) and insulin-like growth factor-1 (IGF1), as enhancing stimuli on human satellite cell cultures, which are preferred sources of stem cells in engineering skeletal muscle tissue. To detect effects on myogenic maturation and proliferation, AlamarBlue® proliferation, assay and semi-quantitative reverse transcription-polymerase chain reaction of following markers was performed: desmin (DES), myogenic factor-5 (MYF5), myogenic differentiation antigen-1 (MYOD1), myogenin (MYOG), myosin heavy chain (MYH) and α1 actin (ACTA1). As a distinct marker of differentiation, immunohistochemical staining and fusion index determination was performed on satellite cell cultures stimulated with IGF1 and IGF1-plus-SMF with an intensity of 80 mT. Proliferation was increased by additional SMF application to IGF1-stimulated cell cultures on the first day of myogenesis. Relative gene expression of measured markers was increased by IGF1 application in the first days of myogenesis except for ACTA1. Additional SMF application enhanced this effect. Nevertheless we were unable to demonstrate the formation of contractile muscle tissue. Immunhistochemical staining verified muscle origin and all markers were displayed. PMID:25189891

  12. The effect of low static magnetic field on osteogenic and adipogenic differentiation potential of human adipose stromal/stem cells

    Marędziak, Monika; Śmieszek, Agnieszka; Tomaszewski, Krzysztof A.; Lewandowski, Daniel; Marycz, Krzysztof

    2016-01-01

    The aim of this work was to investigate the effects of static magnetic field (SMF) on the osteogenic properties of human adipose derived mesenchymal stem cells (hASCs). In this study in seven days viability assay we examined the impact of SMF on cells proliferation rate, population doubling time, and ability to form single-cell derived colonies. We have also examined cells' morphology, ultrastructure and osteogenic properties on the protein as well as mRNA level. We established a complex approach, which enabled us to obtain information about SMF and hASCs potential in the context of differentiation into osteogenic and adipogenic lineages. We demonstrated that SMF enhances both viability and osteogenic properties of hASCs through higher proliferation factor and shorter population doubling time. We have also observed asymmetrically positioned nuclei and organelles after SMF exposition. With regards to osteogenic properties we observed increased levels of osteogenic markers i.e. osteopontin, osteocalcin and increased ability to form osteonodules with positive reaction to Alizarin Red dye. We have also shown that SMF besides enhancing osteogenic properties of hASCs, simultaneously decreases their ability to differentiate into adipogenic lineage. Our results clearly show a direct influence of SMF on the osteogenic potential of hASCs. These results provide key insights into the role of SMF on their cellular fate and properties.

  13. The Effects of Weak Combined Magnetic Field on Cell Wall Regeneration and Frequency of Plant Protoplasts Fusion

    Nedukha, Olena

    The major purpose of these experiments was to investigate plant protoplast fusion frequency and regeneration of a cell wall by protoplasts at weak combined magnetic field (CMF) with the frequency resonance to the cyclotron frequency of Mg2+, Ca2+ and K+ ions. The protoplasts were isolated from Nicotiana lumbaginifolia and N. silvestris leaf mesophyll and from callus tissues (Nicotiana tabacum and Glycine max). The special extra apparatus with ferromagnetic shield was used for estimate of CMF with the frequency resonance to the cyclotron frequency of Mg2+, Ca2+ and K+ ions. The fusion of protoplasts is realized by using of parent protoplasts isolated from one plant species, as well as from various plant species. Control samples were situated near the apparatus with CMF. The laser confocal microscopy was used for study of cell wall regeneration by single and fused protoplasts. The cytochemical methods with DAPI and calcofluor dye were also applied as the detectors for protoplast fusion and regeneration of cell wall. We have been established that CMF with frequency adjusted to the cyclotron frequency Mg2+ ions have shown the most positive influence on regeneration of cell wall by protoplasts. CMF adjusted to the cyclotron frequency of K+ ions very weakly affected on the frequency of protoplast fusion. Largest frequency of protoplasts fusion is noted in the CMF adjusted to the cyclotron frequency of Ca2+ in comparison with the control samples.

  14. In vitro study on apoptotic cell death by effective magnetic hyperthermia with chitosan-coated MnFe2O4

    Oh, Yunok; Lee, Nohyun; Kang, Hyun Wook; Oh, Junghwan

    2016-03-01

    Magnetic nanoparticles (MNPs) have been widely investigated as a hyperthermic agent for cancer treatment. In this study, thermally responsive Chitosan-coated MnFe2O4 (Chitosan-MnFe2O4) nanoparticles were developed to conduct localized magnetic hyperthermia for cancer treatment. Hydrophobic MnFe2O4 nanoparticles were synthesized via thermal decomposition and modified with 2,3-dimercaptosuccinic acid (DMSA) for further conjugation of chitosan. Chitosan-MnFe2O4 nanoparticles exhibited high magnetization and excellent biocompatibility along with low cell cytotoxicity. During magnetic hyperthermia treatment (MHT) with Chitosan-MnFe2O4 on MDA-MB 231 cancer cells, the targeted therapeutic temperature was achieved by directly controlling the strength of the external AC magnetic fields. In vitro Chitosan-MnFe2O4-assisted MHT at 42 °C led to drastic and irreversible changes in cell morphology and eventual cellular death in association with the induction of apoptosis through heat dissipation from the excited magnetic nanoparticles. Therefore, the Chitosan-MnFe2O4 nanoparticles with high biocompatibility and thermal capability can be an effective nano-mediated agent for MHT on cancer.

  15. Cellular Magnetic Resonance Imaging: In Vivo Imaging of Melanoma Cells in Lymph Nodes of Mice1

    Paula J. Foster; Dunn, Elizabeth A; Karl, Kristina E; Snir, Jonatan A; Nycz, Colleen M.; Alfred J Harvey; Ron J Pettis

    2008-01-01

    Metastasis is responsible for most deaths due to malignant melanoma. The clinical significance of micrometastases in the lymph is a hotly debated topic, but an improved understanding of the lymphatic spread of cancer remains important for improving cancer survival. Cellular magnetic resonance imaging (MRI) is a newly emerging field of imaging research that is expected to have a large impact on cancer research. In this study, we demonstrate the cellular MRI technology required to reliably imag...

  16. Magnetic reconnection during collionless, stressed, X-point collapse using Particle-in-Cell simulation

    Tsiklauri, D

    2007-01-01

    Two cases of weakly and strongly stressed X-point collapse were considered. Here descriptors weakly and strongly refer to 20 % and 124 % unidirectional spatial compression of the X-point, respectively. The reconnection rate, defined as the out-of-plane electric field in the X-point (the magnetic null) normalised by the product of external magnetic field and Alfv\\'en speeds, peaks at 0.11, with its average over 1.25 Alfv\\'en times being 0.04. Electron energy distribution in the current sheet, at the high energy end of the spectrum, shows a power law distribution with the index varying in time, attaining a maximal value of -4.1 at the final simulation time step (1.25 Alfv\\'en times). In the strongly stressed case, magnetic reconnection peak occurs 3.4 times faster and is more efficient. The peak reconnection rate now attains value 2.5, with the average reconnection rate over 1.25 Alfv\\'en times being 0.5. The power law energy spectrum for the electrons in the current sheet attains now a steeper index of -5.5, a...

  17. Simulation of microgravity by magnetic levitation and random positioning: Effect on human A431 cell morphology

    M.J.A. Moes; J.C. Gielen; R.J. Bleichrodt; J.J.W.A. van Loon; P.C.M. Christianen; J. Boonstra

    2011-01-01

    Simulation of weightlessness is a desired replenishment for research in microgravity since access to space flights is limited. In real microgravity conditions, the human epidermoid cell line A431 exhibits specific changes in the actin cytoskeleton resulting ultimately in the rounding-up of cells. Th

  18. Multifunctional iron platinum stealth immunomicelles: targeted detection of human prostate cancer cells using both fluorescence and magnetic resonance imaging

    Superparamagnetic iron oxide nanoparticles (SPIONs) are the most common type of contrast agents used in contrast agent-enhanced magnetic resonance imaging (MRI). Still, there is a great deal of room for improvement, and nanoparticles with increased MRI relaxivities are needed to increase the contrast enhancement in MRI applied to various medical conditions including cancer. We report the synthesis of superparamagnetic iron platinum nanoparticles (SIPPs) and subsequent encapsulation using PEGylated phospholipids to create stealth immunomicelles (DSPE-SIPPs) that can be specifically targeted to human prostate cancer cell lines and detected using both MRI and fluorescence imaging. SIPP cores and DSPE-SIPPs were 8.5 ± 1.6 nm and 42.9 ± 8.2 nm in diameter, respectively, and the SIPPs had a magnetic moment of 120 A m2/kg iron. J591, a monoclonal antibody against prostate specific membrane antigen (PSMA), was conjugated to the DSPE-SIPPs (J591-DSPE-SIPPs), and specific targeting of J591-DSPE-SIPPs to PSMA-expressing human prostate cancer cell lines was demonstrated using fluorescence confocal microscopy. The transverse relaxivity of the DSPE-SIPPs, measured at 4.7 Tesla, was 300.6 ± 8.5 s−1 mM−1, which is 13-fold better than commercially available SPIONs (23.8 ± 6.9 s−1 mM−1) and ∼3-fold better than reported relaxivities for Feridex® and Resovist®. Our data suggest that J591-DSPE-SIPPs specifically target human prostate cancer cells in vitro, are superior contrast agents in T2-weighted MRI, and can be detected using fluorescence imaging. To our knowledge, this is the first report on the synthesis of multifunctional SIPP micelles and using SIPPs for the specific detection of prostate cancer.

  19. Canine cerebrospinal fluid total nucleated cell counts and cytology associations with the prevalence of magnetic resonance imaging abnormalities

    Hugo TB

    2014-08-01

    Full Text Available Timothy B Hugo, Kathryn L Heading, Robert H Labuc Melbourne Veterinary Specialist Centre, Glen Waverley, Vic, Australia Introduction: The combination of cerebrospinal fluid (CSF analysis and magnetic resonance imaging (MRI are often used to investigate intracranial disease in dogs. The aim of this retrospective study was to determine if the total nucleated cell count (TNCC or cytology findings in abnormal CSF are associated with the prevalence of MRI abnormalities. Materials and methods: For each case, the TNCC was categorized into one of three groups: A (<25×106/L; B (25–100×106/L; and C (>100×106/L. Cytology findings were categorized by the predominant cell type as lymphocytic, monocytoid, neutrophilic, or eosinopilic. MRI descriptions were classified as either normal or abnormal, and abnormal studies were further evaluated for the presence of specific characteristics (multifocal or diffuse disease versus focal disease, positive T2-weighted hyperintensity, positive FLAIR hyperintensity, contrast enhancement, mass effect, and the presence of poorly or well-defined lesion margins. Results: Forty-five dogs met the inclusion criteria and MRI abnormalities were found in 29/45 (64% dogs. TNCCs were not associated with the prevalence of MRI abnormalities or specific characteristics. Cytology categories were significantly associated with the prevalence of MRI abnormalities (P<0.001. Specifically, monocytoid cytology was 22.8 times more likely to have an abnormal MRI than lymphocytic cytology. CSF cytology was not significantly associated with specific abnormal MRI characteristics. Conclusion: There are minimal associations between CSF abnormalities and the prevalence of MRI abnormalities. These results support the continued importance of utilizing both tests when investigating intracranial disease. When CSF analysis must be performed initially, this study has demonstrated that an abnormal CSF with a monocytoid cytology supports the value of

  20. Nanosized As2O3/Fe2O3 complexes combined with magnetic fluid hyperthermia selectively target liver cancer cells

    Zi-Yu Wang; Jian Song; Dong-Sheng Zhang

    2009-01-01

    AIM: To study the methods of preparing the magnetic nano-microspheres of Fe2O3 and As2O3/Fe2O3 complexes and their therapeutic effects with magnetic fluid hyperthermia (MFH). METHODS: Nanospheres were prepared by chemical co-precipitation and their shape and diameter were observed. Hemolysis, micronucleus, cell viability, and LD50 along with other in vivo tests were performed to evaluate the Fe2O3 microsphere biocompatibility. The inhibition ratio of tumors after Fe2O3 and As2O3/Fe2O3 injections combined with induced hyperthermia in xenograft human hepatocarcinoma was calculated. RESULTS: Fe2O3 and As2O3/Fe2O3 particles were round with an average diameter of 20 nm and 100 nm as observed under transmission electron microscope. Upon exposure to an alternating magnetic field (AMF), the temperature of the suspension of magnetic particles increased to 41-51℃, depending on different particle concentrations, and remained stable thereafter. Nanosized Fe2O3 microspheres are a new kind of biomaterial without cytotoxic effects. The LD50 of both Fe2O3 and As2O3/Fe2O3 in mice was higher than 5 g/kg. One to four weeks after Fe2O3 and As2O3/Fe2O3 complex injections into healthy pig livers, no significant differences were found in serum AST, ALT, BUN and Cr levels among the pigs of all groups (P > 0.05), and no obvious pathological alterations were observed. After exposure to alternating magnetic fields, the inhibition ratio of the tumors was significantly different from controls in the Fe2O3 and As2O3/Fe2O3 groups (68.74% and 82.79%, respectively; P < 0.01). Tumors of mice in treatment groups showed obvious necrosis, while normal tissues adjoining the tumor and internal organs did not.CONCLUSION: Fe2O3 and As2O3/Fe2O3 complexes exerted radiofrequency-induced hyperthermia and drug toxicity on tumors without any liver or kidney damage. Therefore, nanospheres are ideal carriers for tumortargeted therapy.

  1. Integrating Cell Phone Imaging with Magnetic Levitation (i-LEV) for Label-Free Blood Analysis at the Point-of-Living.

    Baday, Murat; Calamak, Semih; Durmus, Naside Gozde; Davis, Ronald W; Steinmetz, Lars M; Demirci, Utkan

    2016-03-01

    There is an emerging need for portable, robust, inexpensive, and easy-to-use disease diagnosis and prognosis monitoring platforms to share health information at the point-of-living, including clinical and home settings. Recent advances in digital health technologies have improved early diagnosis, drug treatment, and personalized medicine. Smartphones with high-resolution cameras and high data processing power enable intriguing biomedical applications when integrated with diagnostic devices. Further, these devices have immense potential to contribute to public health in resource-limited settings where there is a particular need for portable, rapid, label-free, easy-to-use, and affordable biomedical devices to diagnose and continuously monitor patients for precision medicine, especially those suffering from rare diseases, such as sickle cell anemia, thalassemia, and chronic fatigue syndrome. Here, a magnetic levitation-based diagnosis system is presented in which different cell types (i.e., white and red blood cells) are levitated in a magnetic gradient and separated due to their unique densities. Moreover, an easy-to-use, smartphone incorporated levitation system for cell analysis is introduced. Using our portable imaging magnetic levitation (i-LEV) system, it is shown that white and red blood cells can be identified and cell numbers can be quantified without using any labels. In addition, cells levitated in i-LEV can be distinguished at single-cell resolution, potentially enabling diagnosis and monitoring, as well as clinical and research applications. PMID:26523938

  2. Explicit time-reversible orbit integration in Particle In Cell codes with static homogeneous magnetic field

    Patacchini, L.; Hutchinson, I. H.

    2009-04-01

    A new explicit time-reversible orbit integrator for the equations of motion in a static homogeneous magnetic field - called Cyclotronic integrator - is presented. Like Spreiter and Walter's Taylor expansion algorithm, for sufficiently weak electric field gradients this second order method does not require a fine resolution of the Larmor motion; it has however the essential advantage of being symplectic, hence time-reversible. The Cyclotronic integrator is only subject to a linear stability constraint ( ΩΔ t Democritus can reduce the cost of orbit integration by up to a factor of ten.

  3. Cloning and identification of magnetic field-responsive genes in Daudi cells

    2000-01-01

    In order to study the molecular mechanisms of ELF MF biological effects, the differ- ential display (DD) technology has been used to isolate differentially expressed cDNA fragments in Daudi cells after 50 Hz MF exposure and sham-exposure. Using total RNA isolated from 0.8 mT 50 Hz MF exposed cells and those from sham-exposed cells, one differentially regulated transcript has been found by DD and the expression pattern of the same transcript has been verified by reverse-Northern and Northern analyses. DNA sequence analysis and Genbank research demonstrated that the cDNA fragment (MF-CA) is a novel gene in human cell which is induced by ELF MF.

  4. Fast-ignition transport studies: Realistic electron source, integrated particle-in-cell and hydrodynamic modeling, imposed magnetic fields

    Strozzi, D. J.; Tabak, M.; Larson, D. J.; Divol, L.; Kemp, A. J.; Bellei, C.; Marinak, M. M.; Key, M. H. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States)

    2012-07-15

    Transport modeling of idealized, cone-guided fast ignition targets indicates the severe challenge posed by fast-electron source divergence. The hybrid particle-in-cell (PIC) code Zuma is run in tandem with the radiation-hydrodynamics code Hydra to model fast-electron propagation, fuel heating, and thermonuclear burn. The fast electron source is based on a 3D explicit-PIC laser-plasma simulation with the PSC code. This shows a quasi two-temperature energy spectrum and a divergent angle spectrum (average velocity-space polar angle of 52 Degree-Sign ). Transport simulations with the PIC-based divergence do not ignite for >1 MJ of fast-electron energy, for a modest (70 {mu}m) standoff distance from fast-electron injection to the dense fuel. However, artificially collimating the source gives an ignition energy of 132 kJ. To mitigate the divergence, we consider imposed axial magnetic fields. Uniform fields {approx}50 MG are sufficient to recover the artificially collimated ignition energy. Experiments at the Omega laser facility have generated fields of this magnitude by imploding a capsule in seed fields of 50-100 kG. Such imploded fields will likely be more compressed in the transport region than in the laser absorption region. When fast electrons encounter increasing field strength, magnetic mirroring can reflect a substantial fraction of them and reduce coupling to the fuel. A hollow magnetic pipe, which peaks at a finite radius, is presented as one field configuration which circumvents mirroring.

  5. Splenic red pulp macrophages are intrinsically superparamagnetic and contaminate magnetic cell isolates

    Lars Franken; Marika Klein; Marina Spasova; Anna Elsukova; Ulf Wiedwald; Meike Welz; Percy Knolle; Michael Farle; Andreas Limmer; Christian Kurts

    2015-01-01

    A main function of splenic red pulp macrophages is the degradation of damaged or aged erythrocytes. Here we show that these macrophages accumulate ferrimagnetic iron oxides that render them intrinsically superparamagnetic. Consequently, these cells routinely contaminate splenic cell isolates obtained with the use of MCS, a technique that has been widely used in immunological research for decades. These contaminations can profoundly alter experimental results. In mice deficient for the transcr...

  6. Use of chemical fractionation and proton nuclear magnetic resonance to probe the physical structure of the primary plant cell wall

    Proton magnetic resonance has been used to monitor the microscopic physical properties of etiolated hypocotyl cell walls from Phaseolus vulgaris L. at all stages in a series of chemical fractionations with ammonium oxalate and potassium hydroxide. Solid echo measurements indicate that 75% of the polymers in the intact cell wall, including the cellulose and most of the hemicelluloses, are arranged such that there is almost complete restraint of molecular motion. The chemical fractionations generally altered the physical structures of the remaining cell wall components. Digestion with 0.25% ammonium oxalate/oxalic acid solubilized the pectin and increased the mobility of the hemicellulose I component. Extraction with 4% potassium hydroxide removed the hemicellulose I component and loosened the hemicellulose II. Further extraction with 24% potassium hydroxide removed the hemicellulose II and loosened some of the cellulose. The cellulose crystallinity, as monitored by Jeener echo measurements decreased from 83% to 63% during these fractionations. We conclude that, while hemicellulose I is firmly attached to hemicellulose II, it is not in a closely packed structure. Hemicellulose II is strongly bound to cellulose and has a much more closely packed structure

  7. A simple and accurate protocol for absolute polar metabolite quantification in cell cultures using quantitative nuclear magnetic resonance.

    Goldoni, Luca; Beringhelli, Tiziana; Rocchia, Walter; Realini, Natalia; Piomelli, Daniele

    2016-05-15

    Absolute analyte quantification by nuclear magnetic resonance (NMR) spectroscopy is rarely pursued in metabolomics, even though this would allow researchers to compare results obtained using different techniques. Here we report on a new protocol that permits, after pH-controlled serum protein removal, the sensitive quantification (limit of detection [LOD] = 5-25 μM) of hydrophilic nutrients and metabolites in the extracellular medium of cells in cultures. The method does not require the use of databases and uses PULCON (pulse length-based concentration determination) quantitative NMR to obtain results that are significantly more accurate and reproducible than those obtained by CPMG (Carr-Purcell-Meiboom-Gill) sequence or post-processing filtering approaches. Three practical applications of the method highlight its flexibility under different cell culture conditions. We identified and quantified (i) metabolic differences between genetically engineered human cell lines, (ii) alterations in cellular metabolism induced by differentiation of mouse myoblasts into myotubes, and (iii) metabolic changes caused by activation of neurotransmitter receptors in mouse myoblasts. Thus, the new protocol offers an easily implementable, efficient, and versatile tool for the investigation of cellular metabolism and signal transduction. PMID:26898303

  8. Spherical fused silica cells filled with pure helium for nuclear magnetic resonance-magnetometry

    High magnetic fields (>1 T) are measured by NMR magnetometers with unrivaled precision if the precessing spin sample provides long coherence times. The longest coherence times are found in diluted 3He samples, which can be hyperpolarized for sufficient signal strength. In order to have minimal influence on the homogeneity and value of the measured magnetic field, the optimal container for the 3He should be a perfect sphere. A fused silica sphere with an inner diameter of 8 mm and an outer diameter of 12 mm was made from two hemispheres by diffusion bonding leaving only a small hole for cleaning and evacuation. This hole was closed in vacuum by a CO2 laser and the inner volume was filled with a few mbars of 3He via wall permeation. NMR-measurements on such a sample had coherence times of 5 min. While the hemispheres were produced with <1 μm deviation from sphericity, the bonding left a step of ca. 50 μm at maximum. The influence of such a mismatch, its orientation, and the immediate environment of the sample is analyzed by FEM-simulations and discussed in view of coherence times and absolute field measurements

  9. Spherical fused silica cells filled with pure helium for nuclear magnetic resonance-magnetometry

    Maul, Andreas; Blümler, Peter, E-mail: bluemler@uni-mainz.de; Heil, Werner; Nikiel, Anna; Otten, Ernst [Institute of Physics, Johannes Gutenberg University, Staudingerweg 7, 55128 Mainz (Germany); Petrich, Andreas; Schmidt, Thomas [ifw Günter-Köhler-Institut für Fügetechnik und Werkstoffprüfung GmbH, Otto-Schott-Str. 13, 07745 Jena (Germany)

    2016-01-15

    High magnetic fields (>1 T) are measured by NMR magnetometers with unrivaled precision if the precessing spin sample provides long coherence times. The longest coherence times are found in diluted {sup 3}He samples, which can be hyperpolarized for sufficient signal strength. In order to have minimal influence on the homogeneity and value of the measured magnetic field, the optimal container for the {sup 3}He should be a perfect sphere. A fused silica sphere with an inner diameter of 8 mm and an outer diameter of 12 mm was made from two hemispheres by diffusion bonding leaving only a small hole for cleaning and evacuation. This hole was closed in vacuum by a CO{sub 2} laser and the inner volume was filled with a few mbars of {sup 3}He via wall permeation. NMR-measurements on such a sample had coherence times of 5 min. While the hemispheres were produced with <1 μm deviation from sphericity, the bonding left a step of ca. 50 μm at maximum. The influence of such a mismatch, its orientation, and the immediate environment of the sample is analyzed by FEM-simulations and discussed in view of coherence times and absolute field measurements.

  10. Complete hyperfine Paschen-Back regime at relatively small magnetic fields realized in Potassium nano-cell

    Sargsyan, A; Hakhumyan, G; Leroy, C; Pashayan-Leroy, Y; Sarkisyan, D

    2015-01-01

    A one-dimensional nano-metric-thin cell (NC) filled with potassium metal has been built and used to study optical atomic transitions in external magnetic fields. These studies benefit from the remarkable features of the NC allowing one to use $\\lambda/2$- and $\\lambda$-methods for effective investigations of individual transitions of the K D_1 line. The methods are based on strong narrowing of the absorption spectrum of the atomic column of thickness L equal to $\\lambda/2$ and to $\\lambda$(with $\\lambda = 770\\un{nm}$ being the resonant laser radiation wavelength). In particular, for a $\\pi$-polarized radiation excitation the $\\lambda$-method allows us to resolve eight atomic transitions (in two groups of four atomic transitions) and to reveal two remarkable transitions that we call Guiding Transitions (GT). The probabilities of all other transitions inside the group (as well as the frequency slope versus magnetic field) tend to the probability and to the slope of GT. Note that for circular polarization there ...

  11. Osteogenic differentiation of MC3T3-E1 cells on poly(L-lactide)/Fe{sub 3}O{sub 4} nanofibers with static magnetic field exposure

    Cai, Qing [State Key Laboratory of Organic–inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Shi, Yuzhou; Shan, Dingying; Jia, Wenkai; Duan, Shun [Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Deng, Xuliang [Department of Geriatric Dentistry, Peking University School and Hospital of Stomatology, Beijing 100081 (China); Yang, Xiaoping, E-mail: yangxp@mail.buct.edu.cn [State Key Laboratory of Organic–inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029 (China)

    2015-10-01

    Proliferation and differentiation of bone-related cells are modulated by many factors such as scaffold design, growth factor, dynamic culture system, and physical simulation. Nanofibrous structure and moderate-intensity (1 mT–1 T) static magnetic field (SMF) have been identified as capable of stimulating proliferation and differentiation of osteoblasts. Herein, magnetic nanofibers were prepared by electrospinning mixture solutions of poly(L-lactide) (PLLA) and ferromagnetic Fe{sub 3}O{sub 4} nanoparticles (NPs). The PLLA/Fe{sub 3}O{sub 4} composite nanofibers demonstrated homogeneous dispersion of Fe{sub 3}O{sub 4} NPs, and their magnetism depended on the contents of Fe{sub 3}O{sub 4} NPs. SMF of 100 mT was applied in the culture of MC3T3-E1 osteoblasts on pure PLLA and PLLA/Fe{sub 3}O{sub 4} composite nanofibers for the purpose of studying the effect of SMF on osteogenic differentiation of osteoblastic cells on magnetic nanofibrous scaffolds. On non-magnetic PLLA nanofibers, the application of external SMF could enhance the proliferation and osteogenic differentiation of MC3T3-E1 cells. In comparison with pure PLLA nanofibers, the incorporation of Fe{sub 3}O{sub 4} NPs could also promote the proliferation and osteogenic differentiation of MC3T3-E1 cells in the absence or presence of external SMF. The marriage of magnetic nanofibers and external SMF was found most effective in accelerating every aspect of biological behaviors of MC3T3-E1 osteoblasts. The findings demonstrated that the magnetic feature of substrate and microenvironment were applicable ways in regulating osteogenesis in bone tissue engineering. - Highlights: • Magnetic nanofibers containing well-dispersed Fe{sub 3}O{sub 4} nanoparticles were produced. • Static magnetic field (SMF) was applied to perform the culture of osteoblasts. • Osteogenic differentiation was enhanced on magnetic substrate with exposure to SMF.

  12. Noninvasive prenatal diagnosis. Use of density gradient centrifugation, magnetically activated cell sorting and in situ hybridization

    Campagnoli, C; Multhaupt, H A; Ludomirski, A;

    1997-01-01

    centrifugation and dual antibody labeling methods. The protocol was designed to compare the efficacy of antitransferrin receptor (CD71)/antiglycophorin A (GPA) antibodies with antithrom-bospondin receptor (CD36)/anti-GPA antibodies in identifying nucleated erythrocytes in maternal blood. Cytospin preparations...... of the isolated cells were subjected to in situ hybridization with specific DNA probes for the Y chromosome and chromosome 21 to confirm the fetal origin. RESULTS: After MiniMACS the enrichment factors for the CD71/GPA- and CD36/GPA-positive cells from maternal blood were similar, and the percentages of fetal...... cells recovered did not differ. Seven of seven male pregnancies were correctly identified. One case of trisomy 21 was detected. CONCLUSION: The in situ hybridization analysis of fetal nucleated erythrocytes isolated from maternal blood using single density gradient centrifugation, anti-CD71/anti-GPA...

  13. Transport and entry of plasma clouds/jets across transverse magnetic discontinuities: Three-dimensional electromagnetic particle-in-cell simulations

    Voitcu, Gabriel

    2016-01-01

    In this paper we use three-dimensional electromagnetic particle-in-cell simulations to investigate the interaction of a small-Larmor radius plasma cloud/jet with a transverse non-uniform magnetic field typical to a tangential discontinuity in a parallel geometry. The simulation setup corresponds to an idealized, yet relevant, magnetospheric configuration likely to be observed at the magnetopause during northward orientation of the interplanetary magnetic field. The numerical simulations are adapted to study the kinetic effects and their role on the transport and entry of localized plasma jets similar to those identified inside the Earth's magnetosheath propagating towards the magnetopause. The simulations reveal the formation of a polarization electric field inside the main bulk of the plasma cloud that enables its forward transport and entry across the transverse magnetic field. The jet is able to penetrate the transition region when the height of the magnetic barrier does not exceed a certain critical thres...

  14. Intercellular imaging by a polyarginine derived cell penetrating peptide labeled magnetic resonance contrast agent,diethylenetriamine pentaacetic acid gadolinium

    GUO You-min; LIU Min; YANG Jun-le; GUO Xiao-juan; WANG Si-cen; DUAN Xiao-yi; WANG Peng

    2007-01-01

    Background The cellular plasma membrane represents a natural barrier to many exogenous molecules including magnetic resonance (MR) contrast agent. Cell penetrating peptide (CPP) is used to internalize proteins, peptides, and radionuclide. This study was undertaken to assess the value of a new intracellular MR contrast medium, CPP labeled diethylenetriamine pentaacetic acid gadolinium (Gd-DTPA) in molecular imaging in vitro. Methods Fluorescein-5-isothiocyanate (FITC) and Gd-DTPA respectively labeled with CPP (FITC-CPP, Gd-DTPA-CPP) were synthesized by the solid-phase method. Human hepatic cancer cell line-HepG2 was respectively stained by FITC-CPP and FITC to observe the uptake and intracellular distribution. HepG2 was respectively incubated with 100 nmol/ml Gd-DTPA-CPP for 0, 10, 30, 60 minutes, and imaged by MR for studying the relationship between the incubation time and T1WI signal. The cytotoxicity to NIH3T3 fibroblasts cells was measured by 3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide reduction assay (MTT). Results The molecular weights of CPP labeled imaging agents, which were determined by MALDI mass spectrometry (FITC-CPP MW=2163.34, Gd-DTPA-CPP MW=2285.99), were similar to the calculated molecular weights. Confocal microscopy suggested HepG2 translocated FITC-CPP in cytoplasm and nucleus independent with the incubation temperature. MR images showed HepG2 uptaken Gd-DTPA-CPP had a higher T1 weighted imaging (T1WI) signal, and that the T1WI signal intensity was increasing in a time-dependent manner (r=0.972, P=0.001), while the signal intensity between the cells incubated by Gd-DTPA for 60 minutes and the controlled cells was not significantly different (P=0.225). By MTT, all concentrations from 50 nmol/ml to 200 nmol/ml had no significant (F=0.006, P=1.000) effect on cell viability of mouse NIH3T3 fibroblasts, compared with the control group. Conclusions The newly constructed CPP based on polyarginine can translocate cells by carrying FITC

  15. Photon emission from melanoma cells during brief stimulation by patterned magnetic fields: is the source coupled to rotational diffusion within the membrane?

    Dotta, Blake T; Lafrenie, Robert M; Karbowski, Lukasz M; Persinger, Michael A

    2014-01-01

    If parameters for lateral diffusion of lipids within membranes are macroscopic metaphors of the angular magnetic moment of the Bohr magneton then the energy emission should be within the visible wavelength for applied ~1 µT magnetic fields. Single or paired digital photomultiplier tubes (PMTs) were placed near dishes of ~1 million B16 mouse melanoma cells that had been removed from incubation. In very dark conditions (10(-11) W/m(2)) different averaged (RMS) intensities between 5 nT and 3.5 µT were applied randomly in 4 min increments. Numbers of photons were recorded directly over or beside the cell dishes by PMTs placed in pairs within various planes. Spectral analyses were completed for photon power density. The peak photon emissions occurred around 1 µT as predicted by the equation. Spectra analyses showed reliable discrete peaks between 0.9 and 1.8 µT but not for lesser or greater intensities; these peak frequencies corresponded to the energy difference of the orbital-spin magnetic moment of the electron within the applied range of magnetic field intensities and the standard solution for Rydberg atoms. Numbers of photons from cooling cells can be modified by applying specific intensities of temporally patterned magnetic fields. There may be a type of "cellular" magnetic moment that, when stimulated by intensity-tuned magnetic fields, results in photon emissions whose peak frequencies reflect predicted energies for fundamental orbital/spin properties of the electron and atomic aggregates with large principal quantum numbers. PMID:23970034

  16. The effect of magnetic stimulation on the osteogenic and chondrogenic differentiation of human stem cells derived from the adipose tissue (hASCs)

    The use of magnetic nanoparticles (MNPs) towards the musculoskeletal tissues has been the focus of many studies, regarding MNPs ability to promote and direct cellular stimulation and orient tissue responses. This is thought to be mainly achieved by mechano-responsive pathways, which can induce changes in cell behavior, including the processes of proliferation and differentiation, in response to external mechanical stimuli. Thus, the application of MNP-based strategies in tissue engineering may hold potential to propose novel solutions for cell therapy on bone and cartilage strategies to accomplish tissue regeneration. The present work aims at studying the influence of MNPs on the osteogenic and chondrogenic differentiation of human adipose derived stem cells (hASCs). MNPs were incorporated in hASCs and cultured in medium supplemented for osteogenic and chondrogenic differentiation. Cultures were maintained up to 28 days with/without an external magnetic stimulus provided by a magnetic bioreactor, to determine if the MNPs alone could affect the osteogenic or chondrogenic phenotype of the hASCs. Results indicate that the incorporation of MNPs does not negatively affect the viability nor the proliferation of hASCs. Furthermore, Alizarin Red staining evidences an enhancement in extracellular (ECM) mineralization under the influence of an external magnetic field. Although not as evident as for osteogenic differentiation, Toluidine blue and Safranin-O stainings also suggest the presence of a cartilage-like ECM with glycosaminoglycans and proteoglycans under the magnetic stimulus provided. Thus, MNPs incorporated in hASCs under the influence of an external magnetic field have the potential to induce differentiation towards the osteogenic and chondrogenic lineages. - Highlights: • Cellular viability was not negatively influenced by the nanoparticles. • Chondrogenic medium influences more the synthesis of cartilage-like ECM than MNPs. • Synergetic effect among

  17. The effect of magnetic stimulation on the osteogenic and chondrogenic differentiation of human stem cells derived from the adipose tissue (hASCs)

    Lima, João; Gonçalves, Ana I.; Rodrigues, Márcia T.; Reis, Rui L. [3Bs Research Group–Biomaterials, Biodegradables and Biomimetics, University of Minho, Guimarães (Portugal); ICVS/3Bs–PT Government Associate Laboratory, Braga/Guimarães (Portugal); Gomes, Manuela E., E-mail: megomes@dep.uminho.pt [3Bs Research Group–Biomaterials, Biodegradables and Biomimetics, University of Minho, Guimarães (Portugal); ICVS/3Bs–PT Government Associate Laboratory, Braga/Guimarães (Portugal)

    2015-11-01

    The use of magnetic nanoparticles (MNPs) towards the musculoskeletal tissues has been the focus of many studies, regarding MNPs ability to promote and direct cellular stimulation and orient tissue responses. This is thought to be mainly achieved by mechano-responsive pathways, which can induce changes in cell behavior, including the processes of proliferation and differentiation, in response to external mechanical stimuli. Thus, the application of MNP-based strategies in tissue engineering may hold potential to propose novel solutions for cell therapy on bone and cartilage strategies to accomplish tissue regeneration. The present work aims at studying the influence of MNPs on the osteogenic and chondrogenic differentiation of human adipose derived stem cells (hASCs). MNPs were incorporated in hASCs and cultured in medium supplemented for osteogenic and chondrogenic differentiation. Cultures were maintained up to 28 days with/without an external magnetic stimulus provided by a magnetic bioreactor, to determine if the MNPs alone could affect the osteogenic or chondrogenic phenotype of the hASCs. Results indicate that the incorporation of MNPs does not negatively affect the viability nor the proliferation of hASCs. Furthermore, Alizarin Red staining evidences an enhancement in extracellular (ECM) mineralization under the influence of an external magnetic field. Although not as evident as for osteogenic differentiation, Toluidine blue and Safranin-O stainings also suggest the presence of a cartilage-like ECM with glycosaminoglycans and proteoglycans under the magnetic stimulus provided. Thus, MNPs incorporated in hASCs under the influence of an external magnetic field have the potential to induce differentiation towards the osteogenic and chondrogenic lineages. - Highlights: • Cellular viability was not negatively influenced by the nanoparticles. • Chondrogenic medium influences more the synthesis of cartilage-like ECM than MNPs. • Synergetic effect among

  18. Enhancing Tumor Cell Response to Chemotherapy through the Targeted Delivery of Platinum Drugs Mediated by Highly Stable, Multifunctional Carboxymethylcellulose-Coated Magnetic Nanoparticles.

    Medříková, Zdenka; Novohradsky, Vojtech; Zajac, Juraj; Vrána, Oldřich; Kasparkova, Jana; Bakandritsos, Aristides; Petr, Martin; Zbořil, Radek; Brabec, Viktor

    2016-07-01

    The fabrication of nanoparticles using different formulations, and which can be used for the delivery of chemotherapeutics, has recently attracted considerable attention. We describe herein an innovative approach that may ultimately allow for the selective delivery of anticancer drugs to tumor cells by using an external magnet. A conventional antitumor drug, cisplatin, has been incorporated into new carboxymethylcellulose-stabilized magnetite nanoparticles conjugated with the fluorescent marker Alexa Fluor 488 or folic acid as targeting agent. The magnetic nanocarriers possess exceptionally high biocompatibility and colloidal stability. These cisplatin-loaded nanoparticles overcome the resistance mechanisms typical of free cisplatin. Moreover, experiments aimed at the localization of the nanoparticles driven by an external magnet in a medium that mimics physiological conditions confirmed that this localization can inhibit tumor cell growth site-specifically. PMID:27246144

  19. Regional myocardial function after intracoronary bone marrow cell injection in reperfused anterior wall infarction - a cardiovascular magnetic resonance tagging study

    Arnesen Harald

    2011-03-01

    Full Text Available Abstract Background Trials have brought diverse results of bone marrow stem cell treatment in necrotic myocardium. This substudy from the Autologous Stem Cell Transplantation in Acute Myocardial Infarction trial (ASTAMI explored global and regional myocardial function after intracoronary injection of autologous mononuclear bone marrow cells (mBMC in acute anterior wall myocardial infarction treated with percutaneous coronary intervention. Methods Cardiovascular magnetic resonance (CMR tagging was performed 2-3 weeks and 6 months after revascularization in 15 patients treated with intracoronary stem cell injection (mBMC group and in 13 controls without sham injection. Global and regional left ventricular (LV strain and LV twist were correlated to cine CMR and late gadolinium enhancement (LGE. Results In the control group myocardial function as measured by strain improved for the global LV (6 months: -13.1 ± 2.4 versus 2-3 weeks: -11.9 ± 3.4%, p = 0.014 and for the infarct zone (-11.8 ± 3.0 versus -9.3 ± 4.1%, p = 0.001, and significantly more than in the mBMC group (inter-group p = 0.027 for global strain, respectively p = 0.009 for infarct zone strain. LV infarct mass decreased (35.7 ± 20.4 versus 45.7 ± 29.5 g, p = 0.024, also significantly more pronounced than the mBMC group (inter-group p = 0.034. LV twist was initially low and remained unchanged irrespective of therapy. Conclusions LGE and strain findings quite similarly demonstrate subtle differences between the mBMC and control groups. Intracoronary injection of autologous mBMC did not strengthen regional or global myocardial function in this substudy. Trial registration ClinicalTrials.gov: NCT00199823

  20. Application of an improved magnetic immunosorbent in an Ephesia chip designed for circulating tumor cell capture

    Svobodová, Z.; Kučerová, J.; Autebert, J.; Horák, Daniel; Bruckova, L.; Viovy, J.-L.; Bílková, Z.

    2014-01-01

    Roč. 35, 2-3 (2014), s. 323-329. ISSN 0173-0835 R&D Projects: GA MŠk 7E09109 EU Projects: European Commission(XE) 228980 - CAMINEMS Institutional support: RVO:61389013 Keywords : biofunctionalization * circulating tumor cell s * EpCAM Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.028, year: 2014

  1. Magnetic resonance tracking of transplanted stem cells in rat brain and spinal cord

    Syková, Eva; Jendelová, Pavla

    2006-01-01

    Roč. 3, - (2006), s. 62-67. ISSN 1660-2854 R&D Projects: GA ČR(CZ) GA309/06/1594; GA MŠk LC554; GA MŠk 1M0538 Institutional research plan: CEZ:AV0Z50390512 Keywords : Cell transplantation * Nanoparticles * Photochemical lesio Subject RIV: FH - Neurology

  2. The migration of synthetic magnetic nanoparticle labeled dendritic cells into lymph nodes with optical imaging

    Su H

    2013-10-01

    Full Text Available Hang Su,1,* Yongbin Mou,1,* Yanli An,2 Wei Han,1 Xiaofeng Huang,1 Guohua Xia,3 Yanhong Ni,1 Yu Zhang,4 Jianmin Ma,1 Qingang Hu1,5 1Center Laboratory of Stomatology, Stomatological Hospital Affiliated Medical School, Nanjing University, Nanjing, People's Republic of China; 2Jiangsu Key Lab of Molecular and Function Imaging, Department of Radiology; 3Department of Hematology, Zhongda Hospital, Medical School, 4State Key Laboratory of Molecule and Bimolecular Electronics, Jiangsu Provincial Laboratory for Biomaterials and Devices; Southeast University, Nanjing, People's Republic of China; 5Leeds Dental Institute, Faculty of Medicine and health, University of Leeds, Leeds, United Kingdom*These authors contributed equally to this workBackground: The successful biotherapy of carcinoma with dendritic cell (DC vaccines pivotally relies on DCs’ migratory capability into lymph tissues and activation of T cells. Accurate imaging and evaluation of DC migration in vivo have great significance during antitumor treatment with DC vaccine. We herein examined the behavior of DCs influenced by synthetic superparamagnetic iron oxide (SPIO nanoparticle labeling.Methods: γ-Fe2O3 nanoparticles were prepared and DCs, which were induced from bone marrow monocytes of enhanced green fluorescent protein (EGFP transgenic mice, were labeled. The endocytosis of the SPIO, surface molecules, cell apoptosis and fluorescence intensity of EGFP-DCs were displayed by Prussian blue staining and flow cytometry (FCM, respectively. After EGFP-DCs, labeled with SPIO, were injected into footpads (n = 5 for 24 hours, the mice were examined in vivo by optical imaging (OPI. Meanwhile, confocal imaging and FCM were applied, respectively, to detect the migration of labeled DCs into draining lymph nodes.Results: Nearly 100% of cells were labeled by the SPIO, in which the intracellular blue color gradually deepened and the iron contents rose with the increase of labeling iron concentrations

  3. Moderate strength (0.23–0.28 T static magnetic fields (SMF modulate signaling and differentiation in human embryonic cells

    Che Pao-Lin

    2009-08-01

    Full Text Available Abstract Background Compelling evidence exists that magnetic fields modulate living systems. To date, however, rigorous studies have focused on identifying the molecular-level biosensor (e.g., radical ion pairs or membranes or on the behavior of whole animals leaving a gap in understanding how molecular effects are translated into tissue-wide and organism-level responses. This study begins to bridge this gulf by investigating static magnetic fields (SMF through global mRNA profiling in human embryonic cells coupled with software analysis to identify the affected signaling pathways. Results Software analysis of gene expression in cells exposed to 0.23–0.28 T SMF showed that nine signaling networks responded to SMF; of these, detailed biochemical validation was performed for the network linked to the inflammatory cytokine IL-6. We found the short-term ( Conclusion This study provides a framework describing how magnetic exposure is transduced from a plausible molecular biosensor (lipid membranes to cell-level responses that include differentiation toward neural lineages. In addition, SMF provided a stimulus that uncovered new relationships – that exist even in the absence of magnetic fields – between gangliosides, the time-dependent regulation of IL-6 signaling by these glycosphingolipids, and the fate of embryonic cells.

  4. Optimal labeling dose, labeling time, and magnetic resonance imaging detection limits of ultrasmall superparamagnetic iron-oxide nanoparticle labeled mesenchymal stromal cells

    Mathiasen, Anders Bruun; Hansen, Louise; Friis, Tina;

    2013-01-01

    Background. Regenerative therapy is an emerging treatment modality. To determine migration and retention of implanted cells, it is crucial to develop noninvasive tracking methods. The aim was to determine ex vivo magnetic resonance imaging (MRI) detection limits of ultrasmall superparamagnetic iron...

  5. The cytotoxicity evaluation of magnetic iron oxide nanoparticles on human aortic endothelial cells

    Ge, Gaoyuan; Wu, Hengfang; Xiong, Fei; Zhang, Yu; Guo, Zhirui; Bian, Zhiping; Xu, Jindan; Gu, Chunrong; Gu, Ning; Chen, Xiangjian; Yang, Di

    2013-05-01

    One major obstacle for successful application of nanoparticles in medicine is its potential nanotoxicity on the environment and human health. In this study, we evaluated the cytotoxicity effect of dimercaptosuccinic acid-coated iron oxide (DMSA-Fe2O3) using cultured human aortic endothelial cells (HAECs). Our results showed that DMSA-Fe2O3 in the culture medium could be absorbed into HAECs, and dispersed in the cytoplasm. The cytotoxicity effect of DMSA-Fe2O3 on HAECs was dose-dependent, and the concentrations no more than 0.02 mg/ml had little toxic effect which were revealed by tetrazolium dye assay. Meanwhile, the cell injury biomarker, lactate dehydrogenase, was not significantly higher than that from control cells (without DMSA-Fe2O3). However, the endocrine function for endothelin-1 and prostacyclin I-2, as well as the urea transporter function, was altered even without obvious evidence of cell injury in this context. We also showed by real-time PCR analysis that DMSA-Fe2O3 exposure resulted in differential effects on the expressions of pro- and anti-apoptosis genes of HAECs. Meanwhile, it was noted that DMSA-Fe2O3 exposure could activate the expression of genes related to oxidative stress and adhesion molecules, which suggested that inflammatory response might be evoked. Moreover, we demonstrated by in vitro endothelial tube formation that even a small amount of DMSA-Fe2O3 (0.01 and 0.02 mg/ml) could inhibit angiogenesis by the HAECs. Altogether, these results indicate that DMSA-Fe2O3 have some cytotoxicity that may cause side effects on normal endothelial cells.

  6. Effects of combined delivery of extremely low frequency electromagnetic field and magnetic Fe3O4 nanoparticles on hepatic cell lines

    Ju, Huixiang; Cui, Yubao; Chen, Zhiqiang; Fu, Qinping; Sun, Mingzhong; Zhou, Ying

    2016-01-01

    Magnetic Fe3O4 nanoparticles (MNPs) have shown promise as drug carriers for treating lung and liver tumors in vivo. However, little is known about the combined delivery of these MNPs with a second approach, extremely low frequency electro-magnetic field (ELFF) exposure, which has been shown to have value for in vitro treatment of tumor cells. Here, ELFF and MNPs were combined to treat healthy (HL-7702) and cancerous (Bel-7402, HepG2) hepatic cells lines to explore the potential therapeutic effects, bio-mechanisms, and potential toxicity of a combined drug-free treatment in vitro. Flow cytometry for anti-AFP (alpha fetal protein) antibody, which coated the MNPs, indicated that the combined treatment induced Bel-7402 and HepG2 hepatoma cells lines into early apoptosis, without significant effects on healthy hepatic cells. This effect appeared to be mediated through cellular membrane ion metabolism. The presence of AFP-loaded MNPs strengthened the effects of ELFF on tumor cells, inducing a higher frequency of early apoptosis, while having minimal toxic effects on healthy HL-7702 cells. Western blotting revealed that the apoptosis-triggering BCL proteins were up regulated in hepatoma cells compared to healthy cells. Flow cytometry and patch-clamp studies revealed that this resulted from a higher MNP uptake ratio and greater cellular membrane ion exchange current in tumor cells compared to HL-7702 cells. Further, patch-clamp results showed that combining MNPs with ELFF treatment induces cells into early apoptosis through an ion metabolism disturbance in cells, similar to ELFF treatment. In brief, the combination of ELFF and MNPs had beneficial effects on tumor cells without significant toxicity on healthy cells, and these effects were associated with cellular MNP uptake.

  7. Effects of combined delivery of extremely low frequency electromagnetic field and magnetic Fe3O4 nanoparticles on hepatic cell lines.

    Ju, Huixiang; Cui, Yubao; Chen, Zhiqiang; Fu, Qinping; Sun, Mingzhong; Zhou, Ying

    2016-01-01

    Magnetic Fe3O4 nanoparticles (MNPs) have shown promise as drug carriers for treating lung and liver tumors in vivo. However, little is known about the combined delivery of these MNPs with a second approach, extremely low frequency electro-magnetic field (ELFF) exposure, which has been shown to have value for in vitro treatment of tumor cells. Here, ELFF and MNPs were combined to treat healthy (HL-7702) and cancerous (Bel-7402, HepG2) hepatic cells lines to explore the potential therapeutic effects, bio-mechanisms, and potential toxicity of a combined drug-free treatment in vitro. Flow cytometry for anti-AFP (alpha fetal protein) antibody, which coated the MNPs, indicated that the combined treatment induced Bel-7402 and HepG2 hepatoma cells lines into early apoptosis, without significant effects on healthy hepatic cells. This effect appeared to be mediated through cellular membrane ion metabolism. The presence of AFP-loaded MNPs strengthened the effects of ELFF on tumor cells, inducing a higher frequency of early apoptosis, while having minimal toxic effects on healthy HL-7702 cells. Western blotting revealed that the apoptosis-triggering BCL proteins were up regulated in hepatoma cells compared to healthy cells. Flow cytometry and patch-clamp studies revealed that this resulted from a higher MNP uptake ratio and greater cellular membrane ion exchange current in tumor cells compared to HL-7702 cells. Further, patch-clamp results showed that combining MNPs with ELFF treatment induces cells into early apoptosis through an ion metabolism disturbance in cells, similar to ELFF treatment. In brief, the combination of ELFF and MNPs had beneficial effects on tumor cells without significant toxicity on healthy cells, and these effects were associated with cellular MNP uptake. PMID:27186307

  8. Glioma cell density in a rat gene therapy model gauged by water relaxation rate along a fictitious magnetic field.

    Liimatainen, Timo; Sierra, Alejandra; Hanson, Timothy; Sorce, Dennis J; Ylä-Herttuala, Seppo; Garwood, Michael; Michaeli, Shalom; Gröhn, Olli

    2012-01-01

    Longitudinal and transverse rotating-frame relaxation time constants, T(1) (ρ) and T(2) (ρ) , have previously been successfully applied to detect gene therapy responses and acute stroke in animal models. Those experiments were performed with continuous-wave irradiation or with frequency-modulated pulses operating in an adiabatic regime. The technique called Relaxation Along a Fictitious Field (RAFF) is a recent extension of frequency-modulated rotating-frame relaxation methods. In RAFF, spin locking takes place along a fictitious magnetic field, and the decay rate is a function of both T(1ρ) and T(2ρ) processes. In this work, the time constant characterizing water relaxation with RAFF (T(RAFF) ) was evaluated for its utility as a marker of response to gene therapy in a rat glioma model. To investigate the sensitivity to early treatment response, we measured several rotating-frame and free-precession relaxation time constants and the water apparent diffusion coefficients, and these were compared with histological cell counts in 8 days of treated and control groups of animals. T(RAFF) was the only parameter exhibiting significant association with cell density in three different tumor regions (border, intermediate, and core tissues). These results indicate that T(RAFF) may provide a marker to identify tumors responding to treatment. PMID:21721037

  9. In Vivo Targeted Magnetic Resonance Imaging of Endogenous Neural Stem Cells in the Adult Rodent Brain

    Xiao-Mei Zhong

    2015-01-01

    Full Text Available Neural stem cells in the adult mammalian brain have a significant level of neurogenesis plasticity. In vivo monitoring of adult endogenous NSCs would be of great benefit to the understanding of the neurogenesis plasticity under normal and pathological conditions. Here we show the feasibility of in vivo targeted MR imaging of endogenous NSCs in adult mouse brain by intraventricular delivery of monoclonal anti-CD15 antibody conjugated superparamagnetic iron oxide nanoparticles. After intraventricular administration of these nanoparticles, the subpopulation of NSCs in the anterior subventricular zone and the beginning of the rostral migratory stream could be in situ labeled and were in vivo visualized with 7.0-T MR imaging during a period from 1 day to 7 days after the injection. Histology confirmed that the injected targeted nanoparticles were specifically bound to CD15 positive cells and their surrounding extracellular matrix. Our results suggest that in vivo targeted MR imaging of endogenous neural stem cells in adult rodent brain could be achieved by using anti-CD15-SPIONs as the molecular probe; and this targeting imaging strategy has the advantage of a rapid in vivo monitoring of the subpopulation of endogenous NSCs in adult brains.

  10. Transport and phosphorylation of choline in higher plant cells. Phosphorus-31 nuclear magnetic resonance studies

    When sycamore cells were suspended in basal medium containing choline, the latter was taken up by the cells very rapidly. A facilitated diffusion system appertained at low concentrations of choline and exhibited Michaelis-Menten kinetics. At higher choline concentrations simple diffusion appeared to be the principal mode of uptake. Addition of choline to the perfusate of compressed sycamore cells monitored by 31P NMR spectroscopy resulted in a dramatic accumulation of P-choline in the cytoplasmic compartment containing choline kinase and not in the vacuole. The total accumulation of P-choline over a 10-h period exhibited Michaelis-Menten kinetics. During this period, in the absence of Pi in the perfusion medium there was a marked depletion of glucose-6-P, and the cytoplasmic Pi resonance disappeared almost completely. When a threshold of cytoplasmic Pi was attained, the phosphorylation of choline was sustained by the continuous release of Pi from the vacuole although at a much lower rate. However, when 100 microM inorganic phosphate was present in the perfusion medium, externally added Pi was preferentially used to sustain P-choline synthesis. It is clear, therefore, that cytosolic choline kinase associated with a carrier-mediated transport system for choline uptake appeared as effective systems for continuously trapping cytoplasmic Pi including vacuolar Pi entering the cytoplasm

  11. Magnetic super-hydrophilic carbon nanotubes/graphene oxide composite as nanocarriers of mesenchymal stem cells: Insights into the time and dose dependences.

    Granato, Alessandro E C; Rodrigues, Bruno V M; Rodrigues-Junior, Dorival M; Marciano, Fernanda R; Lobo, Anderson O; Porcionatto, Marimelia A

    2016-10-01

    Among nanostructured materials, multi-walled carbon nanotubes (MWCNT) have demonstrated great potential for biomedical applications in recent years. After oxygen plasma etching, we can obtain super-hydrophilic MWCNT that contain graphene oxide (GO) at their tips. This material exhibits good dispersion in biological systems due to the presence of polar groups and its excellent magnetic properties due to metal particle residues from the catalyst that often remain trapped in its walls and tips. Here, we show for the first time a careful biological investigation using magnetic superhydrophilic MWCNT/GO (GCN composites). The objective of this study was to investigate the application of GCN for the in vitro immobilization of mesenchymal stem cells. Our ultimate goal was to develop a system to deliver mesenchymal stem cells to different tissues and organs. We show here that mesenchymal stem cells were able to internalize GCN with a consequent migration when subjected to a magnetic field. The cytotoxicity of GCN was time- and dose-dependent. We also observed that GCN internalization caused changes in the gene expression of the proteins involved in cell adhesion and migration, such as integrins, laminins, and the chemokine CXCL12, as well as its receptor CXCR4. These results suggest that GCN represents a potential new platform for mesenchymal stem cell immobilization at injury sites. PMID:27287169

  12. Improved longitudinal length accuracy of gross tumor volume delineation with diffusion weighted magnetic resonance imaging for esophageal squamous cell carcinoma

    To analyze the longitudinal length accuracy of gross tumor volume (GTV) delineation with diffusion weighted magnetic resonance imaging for esophageal squamous cell carcinoma (SCC). Forty-two patients from December 2011 to June 2012 with esophageal SCC who underwent radical surgery were analyzed. Routine computed tomography (CT) scan, T2-weighted MRI and diffusion weighted magnetic resonance imaging (DWI) were employed before surgery. Diffusion-sensitive gradient b-values were taken at 400, 600, and 800 s/mm2. Gross tumor volumes (GTV) were delineated using CT, T2-weighted MRI and DWI on different b-value images. GTV longitude length measured using the imaging modalities listed above was compared with pathologic lesion length to determine the most accurate imaging modality. CMS Xio radiotherapy planning system was used to fuse DWI scans and CT images to investigate the possibility of delineating GTV on fused images. The differences between the GTV length according to CT, T2-weighted MRI and pathology were 3.63 ± 12.06 mm and 3.46 ± 11.41 mm, respectively. When the diffusion-sensitive gradient b-value was 400, 600, and 800 s/mm2, the differences between the GTV length using DWI and pathology were 0.73 ± 6.09 mm, -0.54 ± 6.03 mm and −1.58 ± 5.71 mm, respectively. DWI scans and CT images were fused accurately using the radiotherapy planning system. GTV margins were depicted clearly on fused images. DWI displays esophageal SCC lengths most precisely when compared with CT or regular MRI. DWI scans fused with CT images can be used to improve accuracy to delineate GTV in esophageal SCC

  13. Hyperthermic potentiation of cisplatin by magnetic nanoparticle heaters is correlated with an increase in cell membrane fluidity

    Alvarez-Berrios MP; Castillo A; Mendez J; Soto O; Rinaldi C; Torres-Lugo M

    2013-01-01

    Merlis P Alvarez-Berríos, Amalchi Castillo, Janet Mendéz, Orlando Soto, Carlos Rinaldi, Madeline Torres-LugoDepartment of Chemical Engineering, University of Puerto Rico, Mayagüez, Puerto RicoAbstract: Magnetic fluid hyperthermia as a cancer treatment method is an attractive alternative to other forms of hyperthermia. It is based on the heat released by magnetic nanoparticles subjected to an alternating magnetic field. Recent studies have shown that magnetic flu...

  14. An effective strategy of magnetic stem cell delivery for spinal cord injury therapy

    Tukmachev, Dmitry; Lunov, Oleg; Zablotskyy, Vitaliy A.; Dejneka, Alexandr; Babič, Michal; Syková, Eva; Kubinová, Šárka

    2015-01-01

    Roč. 7, č. 9 (2015), s. 3954-3958. ISSN 2040-3364 R&D Projects: GA ČR(CZ) GAP304/12/1370; GA MŠk(CZ) LO1309 Grant ostatní: AV ČR(CZ) M100101219 Institutional support: RVO:68378041 ; RVO:68378271 ; RVO:61389013 Keywords : mesenchymal stromal cells * iron-oxide nanoparticles * regenerative medicine * cerebrospinal-fluid * axon growth * recovery * repair * transplantation * promote * model Subject RIV: FH - Neurology; BO - Biophysics (FZU-D); CE - Biochemistry (UMCH-V) Impact factor: 7.394, year: 2014

  15. The effect of magnetic stimulation on the osteogenic and chondrogenic differentiation of human stem cells derived from the adipose tissue (hASCs)

    Lima, João; Gonçalves, Ana I.; Rodrigues, Márcia T.; Reis, Rui L.; Gomes, Manuela E.

    2015-11-01

    The use of magnetic nanoparticles (MNPs) towards the musculoskeletal tissues has been the focus of many studies, regarding MNPs ability to promote and direct cellular stimulation and orient tissue responses. This is thought to be mainly achieved by mechano-responsive pathways, which can induce changes in cell behavior, including the processes of proliferation and differentiation, in response to external mechanical stimuli. Thus, the application of MNP-based strategies in tissue engineering may hold potential to propose novel solutions for cell therapy on bone and cartilage strategies to accomplish tissue regeneration. The present work aims at studying the influence of MNPs on the osteogenic and chondrogenic differentiation of human adipose derived stem cells (hASCs). MNPs were incorporated in hASCs and cultured in medium supplemented for osteogenic and chondrogenic differentiation. Cultures were maintained up to 28 days with/without an external magnetic stimulus provided by a magnetic bioreactor, to determine if the MNPs alone could affect the osteogenic or chondrogenic phenotype of the hASCs. Results indicate that the incorporation of MNPs does not negatively affect the viability nor the proliferation of hASCs. Furthermore, Alizarin Red staining evidences an enhancement in extracellular (ECM) mineralization under the influence of an external magnetic field. Although not as evident as for osteogenic differentiation, Toluidine blue and Safranin-O stainings also suggest the presence of a cartilage-like ECM with glycosaminoglycans and proteoglycans under the magnetic stimulus provided. Thus, MNPs incorporated in hASCs under the influence of an external magnetic field have the potential to induce differentiation towards the osteogenic and chondrogenic lineages.

  16. Alteration of gene expression by exposure to a magnetic field at 23 kHz is not detected in astroglia cells

    The increasing use of induction heating (IH) cooktops has roused public concern in Japan and Europe regarding potential health effects. The purpose of this study was to evaluate the effects of exposure to a magnetic field at 23 kHz (which is the maximum output power frequency of most IH cooktops) on gene expression in a human-fetus-derived astroglia cell line, SVGp12. The cells were exposed to the magnetic field at 2 mTrms [which is approximately 74 times higher than the reference level in the most recent International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines], for 2, 4 and 6 h, using a previously reported exposure system. Gene expression was evaluated using an Agilent cDNA microarray. We did not detect any significant effects of the magnetic field on the gene expression profile. On the contrary, heat treatment at 43°C for 2 h used as a positive control significantly affected gene expression, including inducing heat shock proteins, which indicated that our protocol for microarray analysis was appropriate. From these results, we conclude that exposure of human-fetus-derived astroglia cells to an intermediate-frequency magnetic field at 23 kHz and 2 mTrms for up to 6 h does not induce detectable alteration of gene expression

  17. Magnetically induced electrostimulation of human osteoblasts results in enhanced cell viability and osteogenic differentiation.

    Hiemer, Bettina; Ziebart, Josefin; Jonitz-Heincke, Anika; Grunert, Philip Christian; Su, Yukun; Hansmann, Doris; Bader, Rainer

    2016-07-01

    The application of electromagnetic fields to support the bone-healing processes is a therapeutic approach for patients with musculoskeletal disorders. The ASNIS-III s-series screw is a bone stimulation system providing electromagnetic stimulation; however, its influence on human osteoblasts (hOBs) has not been extensively investigated. Therefore, in the present study, the impact of this system on the viability and differentiation of hOBs was examined. We used the ASNIS-III s screw system in terms of a specific experimental test set-up. The ASNIS-III s screw system was used for the application of electromagnetic fields (EMF, 3 mT, 20 Hz) and electromagnetic fields combined with an additional alternating electric field (EMF + EF) (3 mT, 20 Hz, 700 mV). The stimulation of primary hOBs was conducted 3 times per day for 45 min over a period of 72 h. Unstimulated cells served as the controls. Subsequently, the viability, the gene expression of differentiation markers and pro-collagen type 1 synthesis of the stimulated osteoblasts and corresponding controls were investigated. The application of both EMF and EMF + EF using the ASNIS-III s screw system revealed a positive influence on bone cell viability and moderately increased the synthesis of pro-collagen type 1 compared to the unstimulated controls. Stimulation with EMF resulted in a slightly enhanced gene expression of type 1 collagen and osteocalcin; however, stimulation with EMF + EF resulted in a significant increase in alkaline phosphatase (1.4-fold) and osteocalcin (1.6-fold) levels, and a notable increase in the levels of runt-related transcription factor 2 (RUNX-2; 1.54-fold). Our findings demonstrate that stimulation with electromagnetic fields and an additional alternating electric field has a positive influence on hOBs as regards cell viability and the expression of osteoblastic differentiation markers. PMID:27220915

  18. Polymer-Coated Magnetic Nanoparticles for Curcumin Delivery to Cancer Cells.

    Mancarella, Serena; Greco, Valentina; Baldassarre, Francesca; Vergara, Daniele; Maffia, Michele; Leporatti, Stefano

    2015-10-01

    The new goal of anticancer agent research is the screening of natural origin drugs with lower systemic adverse effects than synthetic compounds. Here, we focus on curcumin, an important polyphenolic pigment classically used as spice in the Indian cuisine. The molecule has high pleiotropic activities including strong antioxidant and anti-inflammatory properties. However, its clinical potential is limited due its low solubility and bioavailability. We have developed a layer by layer functionalization of Fe3 O4 nanoparticles (nano-Fe3 O4 ) by coating biodegradable polyelectrolyte multilayers such as Dextran (DXS) and Poly(l-lysine) (PLL). Physico-chemical studies were performed to obtain a high upload of curcumin in Fe3 O4 nanoparticles. Nano-Fe3 O4 were then tested against an ovarian cancer cell line, SKOV-3, to demonstrate their therapeutic efficacy. PMID:26085082

  19. Elemental speciation in biomolecules by LC-ICP-MS with magnetic sector and collision cell instruments

    A methodology that can monitor and identify inorganic elements in biological and environmental systems was developed. Size exclusion chromatography (SEC) separates biomolecules, which are then nebulized by a microconcentric nebulizer. The resulting aerosol is desolved and introduced into either a high resolution ICP-MS device or a quadrupole device with a collision cell. Because of the high sensitivity and spectral resolution and high sample introduction efficiency, many unusual or difficult elements, such as Cr, Se, Cd and U, can be observed at ambient levels bound to proteins in human serum. These measurements are made in only a few minutes without preliminary isolation and preconcentration steps. Serum samples can be titrated with spikes of various elements to determine which proteins bind a given metal and oxidation state. Experiments concerning the effects of breaking disulfide linkages and denaturation on metal binding in proteins were also investigated. Elemental distribution in liver extract was also obtained

  20. Elemental speciation in biomolecules by LC-ICP-MS with magnetic sector and collision cell instruments

    Wang, Jin

    1999-11-08

    A methodology that can monitor and identify inorganic elements in biological and environmental systems was developed. Size exclusion chromatography (SEC) separates biomolecules, which are then nebulized by a microconcentric nebulizer. The resulting aerosol is desolved and introduced into either a high resolution ICP-MS device or a quadrupole device with a collision cell. Because of the high sensitivity and spectral resolution and high sample introduction efficiency, many unusual or difficult elements, such as Cr, Se, Cd and U, can be observed at ambient levels bound to proteins in human serum. These measurements are made in only a few minutes without preliminary isolation and preconcentration steps. Serum samples can be titrated with spikes of various elements to determine which proteins bind a given metal and oxidation state. Experiments concerning the effects of breaking disulfide linkages and denaturation on metal binding in proteins were also investigated. Elemental distribution in liver extract was also obtained.