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Biodegradable Mg-based materials for stents and bone implants
Zemková, Mária ; Král, Robert (advisor) ; Stráská, Jitka (referee)
The bachelor thesis is focused on the effect of mechanical processing rotary swaging (RS), specifically on the microstructure, mechanical properties and corrosion properties. The investigation was performed on the magnesium alloy AE42 with a different number of RS passes, which can be useful for medical applications. RS is more efficient and cheaper alternative to different material processing methods producing fine-grained struc- ture. Fine-grain structure with grain boundaries with high angle misorientation was achieved by this process. Microstructure was inhomogeneous - the grain size decreased from the surface to the center. An improvement of mechanical properties with the increase in the number of swaging steps was observed. Processing also led to a decrease in corrosion resistance in this alloy. Microstructure development was investigated by electron microscopy scanning. Development of mechanical properties was characterized by compression deformation tests and microhardness measurements. Linear pola- rization method was used for the interpretation of corrosion resistance. 1
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Characterization of ultra-thin polymer films on solid substrates using different physical techniques
Pop-Georgievski, Ognen ; Rypáček, František (advisor) ; Adam, Pavel (referee) ; Werner, Carsten (referee)
The presented doctoral research was aimed at preparation and characterization of ultra thin polymer films on solid substrates using different physical techniques. Each of these physical techniques probes selectively different characteristics of the films. While some of the techniques are strong in the predetermination of some unique properties of the layers, they might be limited and give no specific/conclusive information about some other important characteristics. Therefore, only the combination of the techniques provides a profound picture of the thickness, architecture, composition and functionality of the films/layers. This combined characterization approach elucidates in details the physical characteristics and the mechanisms responsible for the unique behavior of different polymer films/layers in the application that they are intended for. In the thesis, of particular interest were films of high biomedical, biotechnological and tissue engineering importance, such as: 1. poly(lactide) films formed by grafting "from-" a silanized alacrite thin films (L605 Co-based super alloy), 2. polydopamine (PDA) films that could serve as substrate independent mod- ification platform for further surface modification steps, 3. poly(ethylene oxide)films formed by "grafting to-" PDA modified surfaces, 4....
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Biological characteristics of orthopaedic implant surfaces
Ballay, Rastislav ; Landor, Ivan (advisor) ; Džupa, Valér (referee) ; Gallo, Jiří (referee)
Total hip and knee arthroplasty surgeries form an integral part of orthopaedic practice. With an increase of the primary arthroplasty surgeries performed, comes also an increase in the number of complications. The most common complications of these otherwise very successful procedures is periprosthetic joint infections which are also one of the most difficult to treat. In the first part of the study, we evaluated the primary bacterial resistance of the 14 most commonly used materials in the construction of joint prostheses. More specifically, we concentrated on how their surface treatment resists colonisation by specific bacterial species (Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Enterococcus faecalis and Escherichia coli). The studied materials included metal alloys that are commonly used in the weight bearing parts of implants - CoCrNo, FeNiCr and Ti6A14V - but also polymeric and ceramic materials used in the bearing materials, represented by ultra-high- molecular-weight polyethylene (UHMWPE) and aluminium oxide (Al2O3). Our aim was to assess the relationship between material surface roughness and the sensitivity to colonisation by specific bacterial strains and to evaluate their affinity to different materials. Previous studies have proven that the roughness of...
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Study of phytic acid-based organic conversion coatings on magnesium alloys
Zbíral, Roman ; Doskočil, Leoš (referee) ; Buchtík, Martin (advisor)
This thesis deals with organic conversion coatings based on phytic acid, on the magnesium alloys. In theoretical part it deals with corrosion properties of magnesium and magnesium alloys, usage of magnesium alloys for biomedicine applications. There are also summarized information’s about usage of phytic acid, it’s reactions with magnesium and magnesium alloys. At the end of theoretical part is search about phytic acid conversion coatings deposited on magnesium alloys. There are studied optimal conditions for application of phytic acid coatings such as pH, concentration, time of deposition, etc. Based on the knowledge from the theoretical part, a layer based on phytic acid was deposited on the surface of Mg alloy AZ31. The coating was evaluated in the experimental part in terms of its morphology and structure, chemical and corrosion behaviour. Scanning electron microscope (SEM) images showed the presence of microcracks in the dried coating. The chemical nature of the phytic acid-based conversion coating was investigated by energy dispersive spectroscopy (EDS) techniques in combination with Fourier transform infrared spectroscopy (FTIR). The electrochemical corrosion behaviour of Mg alloy AZ31 and coated Mg alloy was investigated by potentiodynamic polarization in Hank's solutions. Based on the obtained values of the corrosion potential and the corrosion current density, it can be stated that the applied layer of the conversion coating leads to an improvement of the corrosion properties. From the results of SEM analysis of samples after exposure in a corrosive environment, it was found that during potentiodynamic measurements no significant manifestation of corrosion attack was observed in coated samples, as was the case with Mg alloy AZ31.
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Hydrogel matrices and nerve regeneration
Šindel, Matej ; Mravec, Filip (referee) ; Pekař, Miloslav (advisor)
Bachelor‘s Thesis is dealing with hydrogel materials appropriate for regeneration of neural tissue or neural tissue engineering. Contains two main parts. First part summarize results of literature research, which points out the complexity of neural system and reveals different demands of individual parts inside neural system. Second part describe simple experiments, where ability of preparation hydrogels using template with linear channels was checked. These linear channels could be filled with another hydrogel, but with different properties. Furthermore, the diffusion of model dyes in prepared linear channels was observed.
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X-ray nano computed tomography of structured polymeric biomaterials
Kalasová, Dominika ; Oberta,, Peter (referee) ; Kataja, Markku (referee) ; Kaiser, Jozef (advisor)
Tato práce se zaměřuje na pokročilou zobrazovací technologii, rentgenovou počítačovou tomografii (CT). Tato nedestruktivní technika je využívána pro výzkum různých biomateiálů ve tkáňovém inženýrství a materiálové vědě obecně (skafoldy, polymery, keramické materiály, kompozity aj.). Vizualizace a kvantifikace ve 3D jsou výhodné v rámci multidisciplinárního přístupu, který je často v těchto odvětvích uplatňován. Záměr této práce lze rozdělit do dvou oblastí. Prvním tématem je optimalizace měřicí procedury různých měkkých materiálů pomocí CT s laboratorními rentgenovými zdroji. To zahrnuje převážně zobrazování ve fázovém kontrastu, konkrétně metodu volného šíření záření (VŠZ). Tato práce teoreticky popisuje VŠZ a demonstruje tento jev na řadě experimentů. Následné nezbytné zpracování dat získaných VŠZ je implementováno a vyhodnoceno na základě míry zlepšení obrazových dat. Druhé téma ukazuje konkrétní aplikace CT v materiálovém inženýrství. Několik studií s různými CT zařízeními ukazuje příklady možných aplikací a obrazového zpracování. Příklady korelace CT dat s jinými doplňkovými technikami ukazují, jak může být CT aplikována v multioborovém přístupu ke komplexnímu řešení vědeckých problémů.
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Study of interaction of HA / biosklo based composites in simulated body fluid
Riša, Juraj ; Švec, Jiří (referee) ; Bartoníčková, Eva (advisor)
This work deals with bioceramic materials based of hydroxyapatite, bioglass and their composites. These materials are commonly used in medicine, especially as hard tissue substituents. They can be prepared by different types of syntheses, from which the most common were picked for this work – precipitation of hydroxyapatite and sol-gel method for bioglass. Thermal analysis and X-ray diffraction were used for characterization of prepared powders. This thesis studies mostly their features within the composite materials, which were foamed for better bone stimulation. Properties and possibility in bio application of materials is firstly studied through their interaction in simulated body fluids, which mimics ionic concentration of human plasma. Experimental part covers synthesis of ceramic powders, their characterization, preparation of mixtures and scaffolds foamed through in situ foaming, their sintering at ideal temperatures, characterization of porosity and phase changes due to sintering. Basic tests of apatite formation ability were provided by incubation of prepared scaffolds in simulated body fluid for 3, 7, 14 and 21 days and their assay in scanning electron microscopy. Changes in concentration of Ca2+ a PO4 3- ions as well as in weight of the specimen were tracked within the incubation period.
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Stem cells in the treatment of spinal cord injury
Juříková, Tereza ; Jendelová, Pavla (advisor) ; Krulová, Magdaléna (referee)
Stem cells are unique thanks to their ability to differentiate into all cell types and self-renewal. They can be used for repairing and functional recovery of various tissues and organs. Regenerative medicine, progressive medical field, use these properties to give a chance to patients with yet incurable health complitations. These include spinal cord injury, which results in huge demyelination and disorders in neurological function. Mesenchymal stem cells contribute to recovery of damaged tissue thanks to its immunomodulatory abilities and production of a number of growth factors. Embryonic stem cells can differentiate into the functional nerve cells, however its use is connected with the posibility of tumorigenesis and also ethical problems. Promising results gives a combinatorial treatment using biomaterials as scaffolds for cells or growth factors. The knowledge of genetic modification of cells will be used in the future. The aim of this thesis is to sumarise current knowledge of the spinal cord treatment with emphasis on tissue specific stem cells. Key words: stem cells - spinal cord injury - tissue recovery - biomaterials
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Biodegradable Mg-based materials for stents and bone implants
Zemková, Mária ; Král, Robert (advisor) ; Stráská, Jitka (referee)
The bachelor thesis is focused on the effect of mechanical processing rotary swaging (RS), specifically on the microstructure, mechanical properties and corrosion properties. The investigation was performed on the magnesium alloy AE42 with a different number of RS passes, which can be useful for medical applications. RS is more efficient and cheaper alternative to different material processing methods producing fine-grained struc- ture. Fine-grain structure with grain boundaries with high angle misorientation was achieved by this process. Microstructure was inhomogeneous - the grain size decreased from the surface to the center. An improvement of mechanical properties with the increase in the number of swaging steps was observed. Processing also led to a decrease in corrosion resistance in this alloy. Microstructure development was investigated by electron microscopy scanning. Development of mechanical properties was characterized by compression deformation tests and microhardness measurements. Linear pola- rization method was used for the interpretation of corrosion resistance. 1
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Nanotechnology and biomaterials for application in cell therapy of spinal cord injury
Vaněček, Václav ; Syková, Eva (advisor) ; Smetana, Karel (referee) ; Haninec, Pavel (referee)
New approaches for the treatment of SCI use advances in the fields of nanotechnology, biomaterial science and cell therapy. The results presented in this thesis showed that superparamagnetic iron oxide nanoparticles coated with a stable dopamine-hyaluronane associate can be used for the safe and effective labeling of MSC. Cell labeling efficiency, viability and the relaxivity of the tested particles were significantly better than those obtained with the commercial particles Endorem®. The DPA-HA coated nanoparticles can be used for the noninvasive monitoring of cell therapy using MRI. Furthermore, we showed that SPION can be used for the targeted delivery of MSC to the site of a spinal cord lesion. The labeled cells can be concentrated in the lesion area by means of a magnetic implant. The process of cell targeting depends on the physical characteristics of the magnetic implant as well as on the biological features of the cells and nanoparticles, as we described with a proposed mathematical model. It is possible to modify the properties of the magnetic system, e.g. by changing the shape or size of the magnet, thus tuning the magnetic force distribution and the gradient of the magnetic field necessary for effective cell targeting. A promising therapeutic strategy for the treatment of spinal cord injury is the...
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