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Novel Antibacterial Collagen Scaffolds for Regenerative Medicine
Dorazilová, Jana ; Brtníková, Jana (oponent) ; Vojtová, Lucy (vedoucí práce)
This master’s thesis deals with the characterisation of 3D porous collagenous sponges enriched with selected antibacterial agents. The literature part of the thesis focuses on the overview of biomaterials and biopolymers with the emphasis on collagen and chitosan, outlines the antibacterial properties of nanoparticles and reviews current aspects of using selenium nanoparticles as an antibacterial agent. For the purpose of this work, two types of antibacterial additives were used – biopolymeric chitosan and selenium nanoparticles. Preparation of 3D porous structure was achieved using the freeze drying method. Mechanical properties of prepared biopolymeric matrices were improved by chemical crosslinking in the presence of carbodiimide. Predominantly physiochemical methods were used for characterization of prepared collagenous sponges. For microstructure analysis, pore size determination, visualisation of nanoparticles and their distribution inside the porous structure, scanning electron microscopy (SEM) with energy dispersive x ray optical analysis (EDX) was used. Parameters such as total porosity, swelling ratio, weight loss during degradation in water and enzymatic environment were evaluated by suitable gravimetric methods. Fourier transformed infrared spectroscopy with attenuated total reflectance (ATR-FTIR) was used to determine changes in the chemical structure of collagenous matrices before and after addition of the antibacterial agents. Percentage release of nanoparticles was evaluated using optical emission spectroscopy with inductively coupled plasma (ICP OES). Evaluation of antibacterial properties of tested samples was carried out mainly by the agar diffusion disk method and the macrodilution broth method. In the conducted research we were able to determine the influence of selected antibacterial additives on the physiochemical properties of 3D collagenous matrices. Their antibacterial activities showed a positive effect on bacterial inhibition of both chitosan and selenium nanoparticles with respect to their concentrations. The designed materials could be further utilized for bio medicinal applications, especially in the field of soft tissue regeneration.
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Tailoring of phase composition and microstructure of calcium phosphate scaffolds applied in regenerative medicine.
Pejchalová, Lucie ; Novotná, Lenka (oponent) ; Salamon, David (vedoucí práce)
Calcium phosphates are the most used ceramic materials for bone regeneration. Calcium phosphates are biocompatible, bioactive and differ in solubility and related degradation in organism. Therefore, calcium phosphate materials are used to regenerate bone defects of small size and as coatings for metallic implants. The solubility of the used materials in body environment after implantation is determined by the ratio of individual calcium phosphates and related degradation rates. This thesis deals with the impact of shaping methods on microstructure and phase composition of calcium phosphates. Commercial hydroxyapatite powder was used as a starting ceramic powder and was treated by calcination at 800 °C for one hour. The biphasic mixture of hydroxyapatite and -tricalcium phosphate was formed during the calcination and this mixture was used for ceramic suspension preparation, with solid loading of 15 vol%, as well as for green bodies preparation. Samples were prepared using several shaping methods: freeze casting, cold isostatic pressing, uniaxial pressing, and slip-casting. Characterization of both, green bodies and sintered samples was performed and the impact of used shaping methods on microstructure and phase composition, was confirmed. It was also observed that the hydroxyapatite content is increasing with increasing porosity, and pore size. This trend applies for samples with unimodal pore size distribution as well as for samples with bimodal pore size distribution.
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Novel Antibacterial Collagen Scaffolds for Regenerative Medicine
Dorazilová, Jana ; Brtníková, Jana (oponent) ; Vojtová, Lucy (vedoucí práce)
This master’s thesis deals with the characterisation of 3D porous collagenous sponges enriched with selected antibacterial agents. The literature part of the thesis focuses on the overview of biomaterials and biopolymers with the emphasis on collagen and chitosan, outlines the antibacterial properties of nanoparticles and reviews current aspects of using selenium nanoparticles as an antibacterial agent. For the purpose of this work, two types of antibacterial additives were used – biopolymeric chitosan and selenium nanoparticles. Preparation of 3D porous structure was achieved using the freeze drying method. Mechanical properties of prepared biopolymeric matrices were improved by chemical crosslinking in the presence of carbodiimide. Predominantly physiochemical methods were used for characterization of prepared collagenous sponges. For microstructure analysis, pore size determination, visualisation of nanoparticles and their distribution inside the porous structure, scanning electron microscopy (SEM) with energy dispersive x ray optical analysis (EDX) was used. Parameters such as total porosity, swelling ratio, weight loss during degradation in water and enzymatic environment were evaluated by suitable gravimetric methods. Fourier transformed infrared spectroscopy with attenuated total reflectance (ATR-FTIR) was used to determine changes in the chemical structure of collagenous matrices before and after addition of the antibacterial agents. Percentage release of nanoparticles was evaluated using optical emission spectroscopy with inductively coupled plasma (ICP OES). Evaluation of antibacterial properties of tested samples was carried out mainly by the agar diffusion disk method and the macrodilution broth method. In the conducted research we were able to determine the influence of selected antibacterial additives on the physiochemical properties of 3D collagenous matrices. Their antibacterial activities showed a positive effect on bacterial inhibition of both chitosan and selenium nanoparticles with respect to their concentrations. The designed materials could be further utilized for bio medicinal applications, especially in the field of soft tissue regeneration.
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Tailoring of phase composition and microstructure of calcium phosphate scaffolds applied in regenerative medicine.
Pejchalová, Lucie ; Novotná, Lenka (oponent) ; Salamon, David (vedoucí práce)
Calcium phosphates are the most used ceramic materials for bone regeneration. Calcium phosphates are biocompatible, bioactive and differ in solubility and related degradation in organism. Therefore, calcium phosphate materials are used to regenerate bone defects of small size and as coatings for metallic implants. The solubility of the used materials in body environment after implantation is determined by the ratio of individual calcium phosphates and related degradation rates. This thesis deals with the impact of shaping methods on microstructure and phase composition of calcium phosphates. Commercial hydroxyapatite powder was used as a starting ceramic powder and was treated by calcination at 800 °C for one hour. The biphasic mixture of hydroxyapatite and -tricalcium phosphate was formed during the calcination and this mixture was used for ceramic suspension preparation, with solid loading of 15 vol%, as well as for green bodies preparation. Samples were prepared using several shaping methods: freeze casting, cold isostatic pressing, uniaxial pressing, and slip-casting. Characterization of both, green bodies and sintered samples was performed and the impact of used shaping methods on microstructure and phase composition, was confirmed. It was also observed that the hydroxyapatite content is increasing with increasing porosity, and pore size. This trend applies for samples with unimodal pore size distribution as well as for samples with bimodal pore size distribution.
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Immunogenicity of stem cells and their derivatives
Doležalová, Nikola ; Holáň, Vladimír (vedoucí práce) ; Kubinová, Šárka (oponent)
Imunogenicita kmenových buněk a jejich derivátů Nikola Doležalová Abstrakt Kmenové buňky mají potenciál v regenerativní medicíně především z důvodu své schopnosti diferenciovat v řadu buněčných linií a také nízké imunogenicity. Ta vyplývá mimo jiné z nízké exprese histokompatibilních antigenů a kostimulačních molekul nebo sekrece tlumivých cytokinů. Imunogenicita tkání odvozených z kmenových buněk byla v minulosti často přehlížena, ale dnes je zřejmé, že rejekce představuje nezanedbatelné riziko při jejich transplantaci. Jejich imunologickým vlastnostem je tedy věnována velká pozornost, aby bylo možné zaručit bezpečnost léčby kmenovými buňkami. Tato bakalářská práce se snaží nastínit současné poznatky o imunogenicitě kmenových buněk a jejich derivátů - zmíněny jsou jak pluripotentní kmenové buňky (embryonální a indukované pluripotentní), tak dospělé kmenové buňky (mezenchymální, limbální, neurální, hematopoetické a kmenové buňky z pupečníkové krve). Exprese imunologicky významných molekul a interakce s buňkami imunitního systému in vitro a in vivo tvoří v této práci základ pro hodnocení imunogenicity. Společně s těmito vlastnostmi budou prezentovány možné způsoby překonání imunologických bariér při transplantaci kmenových buněk. Teprve po pečlivé analýze všech těchto faktorů bude možné poznatky o kmenových...
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