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Hydroxyapatite based ceramic composites
Vojtíšek, Jan ; Ptáček, Petr (referee) ; Bartoníčková, Eva (advisor)
This work was focused on the study of hydroxyapatite based bioceramic materials. These materials are generally very important for medical purposes, especially in the reconstruction and replacement of bone material. For medical applications, inert, bioactive or bioresorbable materials can be used. One of the common "bioactive" materials is hydroxyapatite, which forms a large part of human bone. Hydroxyapatite can be prepared by a wide variety of procedures, one of the most common methods is the precipitation reaction used in this work. To improve the biocompatibility of the bone replacement, porous structures with adequate mechanical stability are used. For the initial study of simulation of the behavior of biomaterials in the human body, called in vitro tests are used in solutions based on synthetic body fluids or cell media. The experimental part deals with the synthesis of hydroxyapatite powder and CA phase composite compounds. The reactions between the individual components were studied by thermal analysis and heat microscopy. The resulting products were analyzed for phase composition by X-ray diffraction. The prepared powders were further processed on foam structures by in situ foaming and sintering at a suitable temperature. In vitro tests, following the behavior of the prepared porous products in the synthetic body fluid, were performed for 7, 14 and 28 days. The monitored composites were then studied for biocompatibility by scanning electron microscopy. At the same time, the change in the concentration of Ca2+ and PO43- ions in the body fluids tested was monitored.
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Silicon substituted calcium phosphate based bioceramic scaffolds
Karkuszová, Karina ; Šťastná, Eva (referee) ; Novotná, Lenka (advisor)
The theoretical part of this bachelor thesis summarizes the current state of knowledge of bioceramic materials based on calcium, phosphorus and silicon. More specifically, it focuses on calcium phosphates, the demands placed on them, the porosity of 3D foams, and biological properties such as biodegradation and bioactivity. 3D bioceramic calcium phosphate foam doped with silicon appears to be a suitable material for use in biomedical applications. It is the silicon that plays a role in the development of healthy bone and the formation of new tissue. Silicon substitutions are important in the field of investigation because they improve the bioassay of phosphate calcium. In the experimental part, calcium phosphate powders were first prepared by the hydroxyapatite and silica fusion reaction. Selected powder contents were 0; 0.1; 1, 2.5, 5, 10 and 20 wt.% SiO2. The samples were sintered at 1100 °C, 1200 °C and 1300 °C. The second part consisted in the preparation of 3D foams by direct penetration with polyurethane and the subsequent characteristics of phase composition, solubility and bioactivity. Bioceramic foams had a highly porous structure. For 42 days, sample behavior in Tris-HCl and simulated body fluid (SBF) was monitored. The results of the experiment have shown that the samples are bioactive and silicon substitution increases phosphate calcium solubility. Therefore, these materials are potentially useful for biomedical applications
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Composite Dental Biomaterials - Structure, Analysis and Properties
Matoušek, Aleš ; Vaněk,, Jiří (referee) ; Lapčík,, Lubomír (referee) ; Cihlář, Jaroslav (advisor)
The aim of this work is to define relations between grain size and bioaktivity of oxide ceramics, specifically ZrO2, Al2O3 and HA. Ceramic materials with grain size from 100 nm up to 10 m, with various surface roughness, were tested for its bioactivity. Ceramography analysis was performed for all tested materials to precisely describe microstructures. Biological properties of the ceramic materials were tested via dilation tests directly in-vitro and by in-vitro extraction. Three cell culturing lines: osteoblast MG63, fibroblast L929, and epithelioid HeLa, were used for our testing. An influence of the grain size on the biological response was only found for the ceramic materials which had been thermally etched. The thermally etched nanocrystalline samples had larger areas covered by cells than ceramics with coarse grain microstructure. Biological tests on layered composites Al2O3×ZrO2 showed the cell selection determined by the type of material, where ZrO2 surfaces were preferably covered. Improved biological response of nanocrystalline ZrO2 was demonstrated on ceramic ZrO2, Al2O3 and SiO2 substrates with nanocrystalline coating of ZrO2. In this work a novel technological process for the formation of defect-free coatings was developed. Sintered coatings were tested using in-vitro technique with cell line HeLa, L929 and MG63 for up to 72 hours. The results of the biological tests of nanocrystalline coatings were consistent with results from the bulk nanocrystalline thermally etched ZrO2 ceramics.
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Study of bioceramic materials on the base of calcium phosphates
Kolář, Martin ; Maca, Karel (referee) ; Cihlář, Jaroslav (advisor)
The literature search on the topic of Bioceramic materials focused in layered materials based on calcium phosphates was written up. Based on knowledge obtained, experiments of preparation of calcium phosphates layered materials based on calcium phosphates by spin-coating method focused in optimalization of layer application conditions were designed and carried out. Experiments of preparation of hydroxyapatite bulk ceramics by uniaxial pressing followed by heat treatment were also performed. Prepared layered and bulk ceramics were characterized from bioactivity point of view by testing of their interaction with simulated body fluid.
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Bioactive ceramic foams – processing, properties testing and applications
Motyka, Jan ; Hadraba, Hynek (referee) ; Řehořek, Lukáš (advisor)
Porous materials for tissue engineering are novel group of materials. They provide some unique properties, namely bioactivity, biodegradability and osteoconductivity. Ceramics porous structure for bone substitutes have considerable potential for applications in medical surgery. But they have poor mechanical properties. Hence they are used for low bearing applications. Those are the reasons for extensive investigation of these materials, mainly in the last few years. Lots of production procedures exist, which leads to production of foams with various shapes and properties.
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Preparation of bioceramic materials for medical applications
Doboš, Petr ; Šoukal, František (referee) ; Palou, Martin (advisor)
The aim of this work was to prepare hydroxyapatite powder by sol-gel and precipitation method. Then, the powders were pressed and sintered at 500 °C, 800 °C and 1100 °C. These samples of HAP were analyzed by FTIR, XRD, SEM methods. The microstructure measurement by SEM indicates that the size HAP particles varies from micro to nano meter. The average size of dominant particles is determined around 5 – 8 µm with surrounding fine particles of 1 µm size. The in vitro bioactivity of HAP samples was investigated by immersing them in Simulated Blood Fluid for 4 weeks. The work reports the result of mikrostructure analysis of samples after immersion. The bioactivity was influenced by the sintering temperature. It is evident, that the layer of the new hydroxyapatite phase formed during immersion on the surface of initial HAP samples changes with temperatures.
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Cytotoxicity of the filamentous cyanobacteria in relation to its ecology
TOMEK, Petr
The aims of this study was to screen a cytotoxic activity in 53 strains of the genera Nostoc and Anabaena and to compare occurence of active isolates within different ecological groups. Selected cytotoxic strains were subjected to HPLC/MS analysis to identify their extracts composition. Isolates with strong cytotoxic effect containing unknown substances were fractionated to obtain pure fraction of this compound. Finally, the selected strains toxicity dependence on time and concentration was evaluated.
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