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Study of interaction of HA / biosklo based composites in simulated body fluid
Riša, Juraj ; Švec, Jiří (oponent) ; Bartoníčková, Eva (vedoucí práce)
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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Žárové nástřiky biokeramiky
Kašpárková, Kristýna ; Mrňa, Libor (oponent) ; Kubíček, Jaroslav (vedoucí práce)
Bakalářská práce je zaměřena na žárové nástřiky biokeramiky. Biokeramika je určena pro náhradu poškozených částí lidského těla. Praktické využití má především v ortopedii, čelistní a obličejové chirurgii. Do této kategorie materiálů patří hydroxyapatit, který se vyznačuje biokompatibilitou a schopností tvořit pevnou vazbu mezi kostí a implantátem. Hydroxyapatit je používán jako povrchový povlak na titanových implantátech. Cílem experimentální části práce byl nástřik 40 – ti kusů zubních implantátů pro firmu LASAK s.r.o. Pro nanesení hydroxyapatitového povlaku byla použita technologie nástřiku plazmou. Požadovaná tloušťka povlaku byla 60 µm. Implantát byl před samotným nástřikem otryskán a očištěn. Nástřik proběhl ve specializované laboratoři dentálních a skeletálních implantátů ÚST FSI VUT Brno. Po nástřiku byla provedena 100% rozměrová kontrola.
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The Synthesis and Characterisation of Biocomposite Materials for Potential Application in Medicine
Balgová, Zuzana ; Plešingerová,, Beatrice (oponent) ; Bakoš, Dušan (oponent) ; Palou, Martin (vedoucí práce)
The work is focused on the synthesis and the study of biocomposite materials for potential medical application. The theoretical part is a literature overview focused on different types of biomaterials especially on poly(vinyl alcohol) - hydroxyapatite (PVA/HA) composites. A set of polyvinyl alcohol (PVA) membranes with various weight percent - 0%, 10%, 20%, 30%, 40% and 50% of hydroxyapatite (HA) were prepared. Hydroxyapatite was prepared by precipitation procedure using starting materials of diammonium hydrogen phosphate and calcium nitrate tetrahydrate in water alkaline environment and then mixed with solution of poly(vinyl alcohol), which was prepared by dissolving it in water at 85°C. The different mixtures were casted in a mould and evaporated for 7 days at temperature 30 °C to obtain 0,5 mm thin membranes. The ATR-FTIR spectroscopy was used to identify the different functional groups in composite membranes, XRD testing was carried out to identify crystallized hydroxyapatite. The tensile testing and TGA measurement were realised to find the effect of HA amount on the mechanical properties and thermal stability of the membranes. The in vitro bioactivity tests in Simulated Blood Fluid (SBF) were performed for 2 hours, 7 and 28 days. SEM was used to characterise surface microstructure of biocomposite membranes before and after immersion in SBF. The surface of the tested membranes were analysed to investigate the formation of apatite, the characteristic of bioactivity. It was observed a formation of clusters within membranes with increasing amount of HA particles due to hydrogen bond and also the agglomeration and crystal growth of HA particles during drying of membranes. The bioactivity was found increasing with time immersion of biocomposite materials.
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Tailoring of cooling procedure during freeze-casting for bone replacement applications.
Šantavý, Tomáš ; Novotná, Lenka (oponent) ; Salamon, David (vedoucí práce)
Bachelor thesis focuses on preparation of hydroxyapatite ceramics by freeze-casting. Hydroxyapatite is an important ceramic material, due to its biocompatibility, biodegradability and bioactivity it has a wide range of use in medicinal applications especially in replacement of bone material. The chosen method, freeze-casting, is flexible, eco-friendly and we are able to achieve a high level of porosity. The method includes freezing, freeze drying and sintering which creates a porous structure of the prepared material. Objective of this bachelor thesis was to find out the impact on the created porosity and mechanical properties of the final material. Freezing rates were applied 3, 4, 5, 6, 7 and 26 m/s. During the experimental part it was established that the freezing rate has a significant influence on the newly formed inner microstructure, it directly influences the interlamellar distances and mechanical property which is compressive strength. With liquid nitrogen with a speed of 26 m/s the achieved compressive strength was of 15 MPa as well as the shortest interlamellar distances of 14-22 µm. With slower freezing rate the average interlamellar distances were 40-150 µm and compressive strength of 2-4 MPa with comparable porosity.
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Antibacterial properties of bioceramic materials
Achberger, Šimon ; Částková, Klára (oponent) ; Salamon, David (vedoucí práce)
Implant surgery carries a risk of infection caused by bacterial contamination of the implant surface. An effective way to inhibit proliferation of bacteria is via antibacterial surfaces, however, their usage is medically and technologically difficult. Previous research shows that cicada wing topography exhibits unique bactericidal properties. In this thesis, various topographies were fabricated using heat treatment under hydrothermal conditions. The goal was to produce a surface covered by high aspect ratio structures with 60–215 nm width and 200–300 nm length. A relative density of 85%, 12 hrs long heat treatment and solution pH 4 and 5,6 had a positive effect on formation of thin surface structures. Quantity of morphological changes was proportional to -tricalcium phosphate content.
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3d shaping of UV curable ceramic feedstock
Mišák, Jiří ; Salamon, David (oponent) ; Graule, Thomas (vedoucí práce)
The aim of this study was the development of printable, UV curable colloidal pastes for 3D robotic deposition of complex ceramic fibre networks. Additionally, shaping techniques of printed structures have been demonstrated. Printable and functional ceramic pastes based on hydroxyapatite have been successfully developed from UV curable compositions. Complex printed ceramic fibre networks and multilayers as well as enhancement of the fibre surface quality have been realised. It has been found that the control of particle-monomer/oligomer-surfactant interactions is essential to achieve printable pastes with adequate rheological properties. Using linear and cross-linking UV curable oligomers as dispersion media, very flexible structures result after UV curing. All printed, cured and additionally shaped structures have been transformed to macroscopic ceramics via thermal debinding and sintering without cracks or delamination between the layers. This has been achieved by using argon atmosphere during curing to prevent oxygen inhibition. The 3D robotic deposition in combination with UV curing is a novel and promising technique to produce complex functional ceramic structures. In this work, the benefits from the combination of 3D robotic deposition and UV solidification have been demonstrated in a new way by using cured and flexible 2 layer structures for folding processes, which lead to 3D structures that are very difficult or impossible to achieve with the employment of just direct 3D robotic deposition. On the basis of this research, versatile theory about preparing ceramic pastes for 3D robotic deposition of complex structures for various applications can be deduced.
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Kompozitní keramické materiály na bázi hydroxyapatitu
Vojtíšek, Jan ; Ptáček, Petr (oponent) ; Bartoníčková, Eva (vedoucí práce)
Tato práce se zabývala studiem biokeramických materiálů na bázi hydroxyapatitu. Tyto materiály jsou obecně velmi důležité pro lékařské účely, zejména při rekonstrukcích a náhradě kostního materiálu. Pro medicínské aplikace je možno využít inertní, bioaktivní nebo bioresorbovatelných materiálů. Jedním z častých „bioaktivních“ materiálů je hydroxyapatit, který tvoří velkou část lidské kosti. Hydroxyapatit je možno připravit velkou řadou postupů, přičemž jednou z nejběžnějších metod je precipitační reakce, která byla použita v této práci. Pro zlepšení biokompatibility kostní náhrady se využívá porézních struktur s odpovídající mechanickou stabilitou. Pro prvotní studium simulace chování biomateriálů v lidském těle se používají tzv. in vitro testy v roztocích na bázi syntetických tělních tekutin či buněčných medií. Experimentální část práce se zabývala syntézou kompozitních sloučenin na bázi hydroxyapatitových prášků a CA fází. Reakce mezi jednotlivými komponenty byla studována pomocí termické analýzy a žárové mikroskopie. Vzniklé produkty byly analyzovány z hlediska fázového složení pomocí rentgenové difrakce. Připravené prášky byly dále zpracovány na pěnové struktury pomocí in situ napěňování a slinutí při vhodné teplotě. In vitro testy, sledující chování připravených porézních produktů v syntetické tělní tekutině, byly provedeny po dobu 7, 14 a 28 dní. Sledované kompozity byly poté studovány z hlediska biokompatibility pomocí skenovací elektronové mikroskopie. Současně byla sledována změna koncentrace Ca2+ a PO43- iontů v testovaných tělních tekutinách.
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Příprava a charakterizace nástřiků hydroxyapatitu deponovaných technologii hybridního vodou-stabilizovaného plazmového hořáku z vodných roztoků
Antoš, Zdeněk ; Tkachenko, Serhii (oponent) ; Čížek, Jan (vedoucí práce)
Povlaky hydroxyapatitu jsou již dlouhou dobu v lékařství používány jako bariéra mezi kovovým jádrem náhrady a okolní živou tkání. Plazmový nástřik je běžně používanou technologií pro tvorbu takových povlaků. Tato práce se zabývá vlastnostmi povlaků hydroxyapatitu vytvořených technologií plazmového nástřiku s hybridním systémem stabilizace oblouku (WSP-H). Zároveň využívá inovativní metodu dávkování výchozího materiálu v podobě vodného roztoku (SPPS). Cílem práce bylo vyrobit vodné roztoky hydroxyapatitu a z nich poté deponovat nástřiky s využitím WSP-H. Tyto nástřiky byly charakterizovány z pohledu morfologie, chemického a fázového složení. Dále byly podrobeny biologickému testování biokompatibility kultivací a následnou analýzou buněk RAW 264.7 a MG-63. Nástřiky vytvořené SPPS vykazují výraznou členitost povrchu, která je vhodná pro biologickou aplikaci. Z testování biokompatibility bylo zjištěno, že tyto povlaky budou v lidském těle dobře tolerovány. Po dostatečné optimalizaci nástřikových parametrů a dosažení fázové čistoty nástřiku bude tento postup výroby povlaku hydroxyapatitu vhodnou náhradou starších metod.
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Structure and Properties of Collagen/HAP Nanocomposite Networks
Kopuletá, Ema ; Lehocký,, Marián (oponent) ; Amler,, Evžen (oponent) ; Jančář, Josef (vedoucí práce)
Polymer-based materials are some of the most promising materials for tissue engineering and controlled drug delivery. Collagen, as one of the most abundant proteins to be found in mammals, is especially interesting due to its tunable properties and excellent host reactions. This thesis is focused on the self-assembly and the mechanical properties of collagen in solution, its kinetics and general principles controlling the process. The effect of hydroxyapatite nanoparticles on the collagen self-assembly and mechanical properties is also investigated. Possible mechanisms of collagen/hydroxyapatite interactions are elucidated along with the description of structure evolution and properties at various structural levels. The shear rate dependences and viscoelastic behavior of collagen I and its nanocomposites with hydroxyapatite (HAP) were measured and interpreted molecularly. The structure of collagen I scaffolds was studied and the effect of HAP and cross-linking was determined. Finally, the results were discussed in terms of the applicability of collagen/hydroxyapatite nanocomposites in scaffolds for bone tissue regeneration.
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