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Effect of body fluids on setting, structure and mechanical properties of phosphate bone cements
Bednaříková, Vendula ; Michlovská, Lenka (oponent) ; Vojtová, Lucy (vedoucí práce)
Presented diploma thesis describes the preparation and characterization of composite calcium-phosphate bone cements (CPCs). In the literature review properties and structure of tricalcium phosphates (TCPs) are described, including their interaction with body environment. In the experimental work, first of all, sample preparation technique was determined by experiments with setting reactions provided in ultrapure water environment. Optimal technique of setting CPC samples included memory foam setting mold, ending setting reactions by absolute cold ethanol and vacuum drying procedures. Consequently, the work describes the sample preparation and process of TCP bone cement setting in both natural (pig blood) and simulated body fluids (physiological, Hank´s and Ringer´s solutions). Morphology study by Scanning Electron Microscopy (SEM) was performed for samples set for 1 day, 1 week, 2 weeks and 1 month, due to the significant change in crystalline structure proving as well by X-ray diffraction (XRD) analysis by determining -TCP conversion to calcium-deficient hydroxyapatite (CDHA). Porosity investigated by X-ray computed microtomography (-CT) was slightly higher at sample set in natural blood. Mechanical properties of CPC samples measured by mechanical compression tests showed stable cement strength set in physiological solution already after 1 day while cements set in blood has shown still increasing strength even at 1 month. On contrary, strength of cement samples rapidly decreased after 2 weeks of setting in both Hank´s and Ringer´s solutions probably due to its slightly acidic pH accelerating CPC disintegration. As a result, setting environment has significant effect on resulting CPC properties and natural blood in comparison to simulated plasma had shown better CPC properties while more closely imitating the in vivo conditions.
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Optimization of antibacterial properties of polymer-phosphate bone fillers
Grézlová, Veronika ; Michlovská, Lenka (oponent) ; Vojtová, Lucy (vedoucí práce)
Proposed diploma thesis is focused on the preparation of polymer-phosphate bone cement. The aim is to optimize antibacterial properties of the cement by adding selenium nanoparticles (SeNPs). The theoretical part describes the characteristics of bone, properties od tricalcium phosphate (TCP) and its polymorphs, the use of bone cement and antibacterial nanoparticles in medicine. The experimental part deals with the preparation of samples, description of the used methods and evaluation of the effect of SeNPs on the bone cement setting reaction, morphology, crystallinity, mechanical, rheological and antibacterial properties. As a result, SeNPs improved bone cement injectability and increased setting reaction with the positive effect on cement mechanical properties. Antibacterial properties of samples were tested using both disk and dilution method resulting in the positive inhibition effect of SeNPs on gram-positive bacteria (G+), especially Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus. The quantitative SeNPs release from modified polymer-phosphate bone cement enable its use as antibacterial bone filler (e.g. for osteomyelitis treating).
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Investigation of the flow characteristics of bone cements during cementation.
Zezula, Miroslav ; Poláček, Petr (oponent) ; Jančář, Josef (vedoucí práce)
Nowadays surgeons concern of the effect of viscosity of cement on cement penetration in the total joint replacement. Cement penetration depend on cement viscosity, prosthesis insertion time, cement curing time etc. The viscosity of bone cements is determined by the chemical composition, the temperature and the powder to monomer ratio. In this study will compaired viscosity and penetration into the bone of high and low viscosity cements. Viscosity will measured by two models. In first model the rod is insered in the cement with constant speed. In second model the cement is injected out from a syringe with constant speed. Cement penetration after injection into the bone will be measured by X-ray.
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The effect of biopolymers on adhesive and rheological properties of calcium phosphate bone cements
Scholz, David ; Michlovská, Lenka (oponent) ; Vojtová, Lucy (vedoucí práce)
This thesis deals with bone cement composed of tricalcium phosphate and thermosensitive copolymer. The main aim was to improve especially the adhesive properties of the cement by adding polysaccharide. The theoretical part of the thesis deals with the characterization of bone cements and their application and also a description of polymeric additives used in bone cements mainly focused on polysaccharides. In the experimental part, the prepared cements were characterized using rheology, powder X-ray diffraction and static mechanical tests on the cured cement alone and glued bones. Rheology was used to measure the setting time of the cements as a function of time and temperature. Furthermore, rheology was also intended to measure the adhesive properties of copolymer solutions, but this was not possible due to the nonreproducible results caused by inhomogeneity of the copolymer solutions with polysaccharide. Powder X-ray diffraction was used to measure the effect of polysaccharide on the conversion of tricalcium phosphate to calcium deficient hydroxyapatite. It was found out that polysaccharide does not significantly affect the conversion of tricalcium phosphate. Static mechanical tests were used to measure maximal compressive strength for the cured cement samples and also to measure the adhesion strength of glued bone samples. Cured samples with low polysaccharide concentration showed higher compressive strength compared to control samples. Inconclusive results were obtained during testing of the bone samples due to the complexity of the measurement. In particular, it concerns the preparation of bone samples and their gluing with bone cement.
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Optimization of antibacterial properties of polymer-phosphate bone fillers
Grézlová, Veronika ; Michlovská, Lenka (oponent) ; Vojtová, Lucy (vedoucí práce)
Proposed diploma thesis is focused on the preparation of polymer-phosphate bone cement. The aim is to optimize antibacterial properties of the cement by adding selenium nanoparticles (SeNPs). The theoretical part describes the characteristics of bone, properties od tricalcium phosphate (TCP) and its polymorphs, the use of bone cement and antibacterial nanoparticles in medicine. The experimental part deals with the preparation of samples, description of the used methods and evaluation of the effect of SeNPs on the bone cement setting reaction, morphology, crystallinity, mechanical, rheological and antibacterial properties. As a result, SeNPs improved bone cement injectability and increased setting reaction with the positive effect on cement mechanical properties. Antibacterial properties of samples were tested using both disk and dilution method resulting in the positive inhibition effect of SeNPs on gram-positive bacteria (G+), especially Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus. The quantitative SeNPs release from modified polymer-phosphate bone cement enable its use as antibacterial bone filler (e.g. for osteomyelitis treating).
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Effect of body fluids on setting, structure and mechanical properties of phosphate bone cements
Bednaříková, Vendula ; Michlovská, Lenka (oponent) ; Vojtová, Lucy (vedoucí práce)
Presented diploma thesis describes the preparation and characterization of composite calcium-phosphate bone cements (CPCs). In the literature review properties and structure of tricalcium phosphates (TCPs) are described, including their interaction with body environment. In the experimental work, first of all, sample preparation technique was determined by experiments with setting reactions provided in ultrapure water environment. Optimal technique of setting CPC samples included memory foam setting mold, ending setting reactions by absolute cold ethanol and vacuum drying procedures. Consequently, the work describes the sample preparation and process of TCP bone cement setting in both natural (pig blood) and simulated body fluids (physiological, Hank´s and Ringer´s solutions). Morphology study by Scanning Electron Microscopy (SEM) was performed for samples set for 1 day, 1 week, 2 weeks and 1 month, due to the significant change in crystalline structure proving as well by X-ray diffraction (XRD) analysis by determining -TCP conversion to calcium-deficient hydroxyapatite (CDHA). Porosity investigated by X-ray computed microtomography (-CT) was slightly higher at sample set in natural blood. Mechanical properties of CPC samples measured by mechanical compression tests showed stable cement strength set in physiological solution already after 1 day while cements set in blood has shown still increasing strength even at 1 month. On contrary, strength of cement samples rapidly decreased after 2 weeks of setting in both Hank´s and Ringer´s solutions probably due to its slightly acidic pH accelerating CPC disintegration. As a result, setting environment has significant effect on resulting CPC properties and natural blood in comparison to simulated plasma had shown better CPC properties while more closely imitating the in vivo conditions.
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Stanovení vankomycinu a jeho termodegradačních produktů pomocí HPLC
Neščáková, Monika ; Klapková, Eva (vedoucí práce) ; Kotaška, Karel (oponent)
Cílem této bakalářské práce bylo zavést a validovat metodu pro stanovení vankomycinu a jeho termodegradačních produktů pomocí vysokoúčinné kapalinové chromatografie s detekcí pomocí detektoru diodového pole. Tato metoda, na rozdíl od imunochemických metod, dokáže spolehlivě detekovat a rozlišit termodegradační produkty vankomycinu, které postrádají potřebnou léčebnou účinnost a při dlouhodobém podávání vankomycinu či při renální insuficienci dochází k jejich hromadění v těle. Dalším cílem této práce bylo monitorování koncentračního profilu uvolňování vankomycinu a jeho termodegradačních produktů z lokálních nosičů antibiotik, která se využívají při složitých ortopedických operacích jako prevence vzniku zánětlivých infekcí vyvolaných Staphylococcus aureus. Bylo porovnáno uvolňování vankomycinu in vitro ze dvou různých kostních cementů, z kostních štěpů a ze syntetického kostního štěpu. Cílem bylo zjistit, zda se z daných materiálů uvolňuje takové množství vankomycinu, které zajistí dlouhodobě vyšší lokální koncentrace vankomycinu, než je MIC vankomycin-rezistentních kmenů Staphylococcus aureus (VRSA). Powered by TCPDF (www.tcpdf.org)
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Investigation of the flow characteristics of bone cements during cementation.
Zezula, Miroslav ; Poláček, Petr (oponent) ; Jančář, Josef (vedoucí práce)
Nowadays surgeons concern of the effect of viscosity of cement on cement penetration in the total joint replacement. Cement penetration depend on cement viscosity, prosthesis insertion time, cement curing time etc. The viscosity of bone cements is determined by the chemical composition, the temperature and the powder to monomer ratio. In this study will compaired viscosity and penetration into the bone of high and low viscosity cements. Viscosity will measured by two models. In first model the rod is insered in the cement with constant speed. In second model the cement is injected out from a syringe with constant speed. Cement penetration after injection into the bone will be measured by X-ray.
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