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Properties and application of ferrofluids
Vaverka, Jakub ; Šedivý, Dominik (referee) ; Zbavitel, Jan (advisor)
Ferrofluids are substances that can change their properties through an external magnetic field. The theoretical part of this bachelor thesis explains the nature and properties of these liquids, and how they are made. The next chapter provides concrete examples of ferrofluid use, and where it is possible to direct current research. The principal objective of the experimental part is to measure and evaluate the surface tension of two different samples of kerosene-based ferrofluids.
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Use of nanomagnets treated materials in study of decomposition
Vyhnálek, Michal ; Frouz, Jan (advisor) ; Veselá, Hana (referee)
In study of soil organic matter, many methods of carbon labeling are used, mostly using carbon isotope 13 C, which are reliable, but require expensive devices. Magnetic nanoparticles could provide low-cost alternative, which can be prepared in most laboratories with basic equipment. The upside of nanoparticles usage is the fact, that we could monitor fate of individual particles added to soil, including their chemical transformations or changes in microbial communities. The goal of this paper was to test the usage of magnetic nanoparticles and prove the reliability of carbon labeling through experiment. KEY WORDS Magnetic nanoparticles, decomposition, soil organic matter
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Preparation and characterization of bi-phasic magnetic nanoparticles
Alemayehu, Adam ; Tyrpekl, Václav (advisor) ; Brázda, Petr (referee)
Title: Preparation and characterization of bi-phasic magnetic nanoparticles Author: Bc. Adam Alemayehu Department: Department of Innorganic Chemistry Supervisors: doc. RNDr. Daniel Nižňanský, Ph.D. RNDr. Václav Tyrpekl, Ph.D. Consultant: M.Sc. Dominika Zákutná Abstract The work is focusing on the magnetic properties of ferrimagnetic spinel ferrites before and after the introduction of a shell on a core particle with different magnetic properties. The core nanoparticles were prepared by hydrothermal decomposition of oleate precursors. The introduction of shell was carried out by hydrothermal treatment of the already prepared core particles. The phase composition, spinel structure and the sizes of the prepared samples were investigated by powder X-ray diffraction and by transmission electron microscopy. Formation of the shell on top of the core particle was determined indirectly, using Mössbauer spectroscopy at room temperature. The interparticle interactions and the particle shape was studied by small angle X-ray scattering. The magnetic properties of the prepared samples were measured on a SQUID magnetometer. Key words: magnetic nanoparticles, core, shell, spinel structure, powder X-ray diffraction, Mössbauer spectroscopy, magnetic measurements, TEM
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Nanoparticles formed by complexes of copolymers with low-molar-mass compounds
Vojtová, Jana ; Štěpánek, Miroslav (advisor) ; Filippov, Sergej (referee) ; Hoffmann, Ingo (referee)
This thesis is focused on mixed systems of various copolymers (double hydrophilic block and gradient polyelectrolytes, hydrophobic graft copolymers) and low-molar-mass compounds (sodium dodecyl sulfate as a representative of a ionic surfactant or superparamagnetic iron oxides in the form of nanocrystals). The electrostatic and hydrophobic interactions in the studied systems in aqueous solutions leading to aggregation behavior and to the formation of co-assembled nanoparticles were investigated by combination of scattering and microscopy techniques, including light, X-ray and neutron scattering, electron microscopy and atomic force microscopy. Powered by TCPDF (www.tcpdf.org)
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Cell labeling with magnetic particles
Kukhta, Dziyana ; Janoušek, Oto (referee) ; Čmiel, Vratislav (advisor)
This bachelor thesis describes the movement of cells labelled with magnetic nanoparticles in the magnetic field in the direction of the magnet. First, it describes two types of magnets: permanent magnet and electromagnet. Then, it is dedicated to magnetic field sensors, magnetic nanoparticles and their incorporation in cells, optical systems for detecting cell movement and the effect of electromagnetic fields on cells. The practical part is dedicated to the incorporation of nanoparticles in cells, the measurement of the magnetic field intensity of a neodymium magnet and an electromagnet, and the methods of electromagnet control. It also describes the effect of electromagnetic fields on fibroblasts and the concentration of nanoparticles on the ability of the labelled cells to react to a magnetic field. The last part is dedicated to the production of a flow chamber, the analysis of the movement of cells in the chamber and the subsequent capture of cells in various magnetic fields.
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The application of magnetic particles for DNA isolation from thermally processed food products
Hronová, Aneta ; Rittich, Bohuslav (referee) ; Kovařík, Aleš (advisor)
The thesis has been focused on testing of micromethod of DNA isolation using magnetic particles from thermic-managed food products in a quality suitable for polymerase chain reaction (PCR). Currant jams were selected for the analysis. These were homogenized using plastic copist and stomacher in lysis buffer with cetyltrimethylammonium bromide (CTAB). The effect of chloroform-octanol and isopropanol in the preparation of homogenates was tested. Homogenates were used for DNA isolation by magnetic particles. Rough fraction of DNA was purified by binding on the magnetic particles after centrifugation of the CTAB complexes with proteins, polyphenols and polysaccharides. Two types of magnetic particles were tested: microparticles of poly(hydroxyethylmethacrylate-co-glycidylmethacrylate) - P(HEMA-co-GMA) and nanoparticles of iron oxides covered by poly(L-lysine) - PLL. Isolated DNA was analyzed spectrophotometrically - it was assessed its concentration and contamination by polyphenols and proteins. After that, amplification of the DNA was tested in PCR. Primers specific for plant ribosomal DNA were used. PCR products of expected length 700 bp were detected by agarose gel electrophoresis. It was shown that DNA isolated from currant jams using magnetic particles was in PCR-ready quality.
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The role of sonication of polyethyleneoxide solutions containing magnetic nanoparticles on morphology of nanofibrous mats
Peer, Petra ; Stěnička, M. ; Filip, Petr ; Pizúrová, Naděžda ; Babayan, V.
Properties of the resulting polymer nanofibers are often tailored by sonication technique applied prior or past an electrospinning process. The aim of this contribution is to evaluate morphology of nanofibrous mats formed by poly(ethylene oxide) with distributed magnetic nanoparticles (MNP) (about 20 nm in diameter) in dependence on time of sonication of the used polymer solutions. The solutions were exposed to sonication (intensity 200W, frequency 24 kHz) for 10, 30, and 60 minutes. It was shown that rheological characteristics (viscosity, storage and loss moduli) strongly depend on time of sonication (particularly phase angle) in contrast to electric conductivity and surface tension. For analysis of homogeneous distribution of MNP in polymer solution, the rheological measurements were carried out also in presence of external magnetic field. Magnetorheological efficiency (a relation of corresponding viscosities) was determined for 80, 170, and 255 mT. Consequently, changed rheological characteristics participate significantly in the process of electrospinning and resulting quality of the obtained nanofibrous mats. Qualitative changes were described by\nmeans of scanning electron microscopy (variance of mean diameter of nanofibers), transmission electron microscopy (distribution of MNP within nanofibrous mats). Static magnetic properties were determined by a vibration sample magnetometer. It was shown that even distribution of MNP in the mats can be achieved by mere sonication process without application of external magnetic field during an electrospinning process. However, time of sonication generates a degree of embedding of MNP into individual nanofibers.
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Nanoparticles formed by complexes of copolymers with low-molar-mass compounds
Vojtová, Jana
This thesis is focused on mixed systems of various copolymers (double hydrophilic block and gradient polyelectrolytes, hydrophobic graft copolymers) and low-molar-mass compounds (sodium dodecyl sulfate as a representative of a ionic surfactant or superparamagnetic iron oxides in the form of nanocrystals). The electrostatic and hydrophobic interactions in the studied systems in aqueous solutions leading to aggregation behavior and to the formation of co-assembled nanoparticles were investigated by combination of scattering and microscopy techniques, including light, X-ray and neutron scattering, electron microscopy and atomic force microscopy. Powered by TCPDF (www.tcpdf.org)
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Magnetic Nanoparticles for Targeted Delivery System of Plasmid into HEK293 cells
Bílek, Ondřej ; Svoboda, Ondřej (referee) ; Fohlerová, Zdenka (advisor)
This bachelor’s thesis deals with using of magnetic nanoparticles, SPIO nanoparticles and nanoparticles of commercial product MATra for transfection of ASAP plasmid into HEK293 cells and subsequent optimization of the process. The experimental part is enclosed with theorethical part that summarizes findings from the fields of synthesis of magnetic nanoparticles and their biomedical applications, theory dealing with possibilities of the insertion of foreign DNA or plasmids into the cell and of its efficiency evaluation.
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