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Preparation and characterization of complex liposomal for drug delivery systems
Szabová, Jana ; Pekař, Miloslav (referee) ; Mravec, Filip (advisor)
This diploma thesis deals with the preparation and characterization of stealth liposomes and their combination with trimethylchitosan (TMC). This complex could find application in the field of inhalation administration. Stealth liposomes were prepared from neutral phophatidylcholine, negatively charged fosfatidic acid and polyethyleneglycol bounded to phosphatidylethanolamine. We have managed to prepare stealth liposomes with suitable properties that should guarantee passive targeting without evocation an immune response, despite the content of the negative component. We also found a suitable method of preparation for stealth liposome–TMC complex, where the change of size and zeta potential confirmed the non–covalent bound between two components despite the content of the polyethyleneglycol.
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Interactions of polycations and anionic surfactants
Szabová, Jana ; Krouská, Jitka (referee) ; Mravec, Filip (advisor)
This thesis deals with the study of interaction polycations and anionic sufactants with regard to phase separation in water and in physiological saline solution (0.15 moldm3 NaCl). First, the solubilizing experiments were made (using hydrophobic dye red oil O) for mapping behavior system SDS-DEAE. Then the aggregation behavior of surfactant was measured. Using solubilizing experiments the area for influence of addition dextran hydrochloride for aggregation was selected. This behavior was investigated by fluorescence spectroscopy using pyrene as fluorescence probe. The Critical Micellar and Agregation Concentration of studied system was determined and defined the area of phase separation. The influence of the process of preparing hydrogels by dry or wet path was studeid. The measurements revealed that the addition of salt and polymer has a considerable influence on value of CAC. It was also found, that increasing ionic strength affects the formation of a hydrogel. Finally, it was found that the process of preparing hydrogels does not affect formation of hydrogel.
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Study of the hydration shell of vesicular systems based on ionic amphiphilic pairs
Rašticová, Barbora ; Szabová, Jana (referee) ; Mravec, Filip (advisor)
This bachelor thesis deals with the study of hydration shell of positively charged vesicular systems. The aim of the work was to monitor the hydration shell and to find out the amount of water molecules in the environment at different conditions of the membrane. Furthermore, a comparison of two selected fluorescent probes were studied. Positively charged vesicular systems composed of two types of surfactants were used, namely negatively charged SDS and positively charged CTAB. The two-chain positively charged surfactant was also added, resulting a positively charged vesicular systems. Three different concentrations of cholesterol were selected for the study and added to the system, namely 20, 40 and 60 mol. %. The study was performed by measuring the fluorescent emission as a function of temperature. The temperature range was from 10 to 80 °C. As a fluorescent probe Laurdan and Prodan were selected. For evaluation the method of generalized polarization was used. Due to its structure, Laurdan is mainly found in the membrane environment, so the method of two-wavelength generalized polarization, which includes fluorescence contributions only from the membrane, was sufficient for its evaluation. Compared to Laurdan, Prodan has a shorter hydrocarbon chain, so its distribution is not only in the membrane but also in the aqueous environment. Therefore, the method of three-wavelength generalized polarization, which also includes the contribution of fluorescence from the aqueous environment was used. The results showed that the behaviour of both probes is very similar. In all systems, the values of generalized polarization decreased with increasing temperature. Thus, at low temperatures, the membrane is in a solid ordered phase. With increasing temperature, it transforms into a liquid disordered phase. Thus, with increasing temperature, the number of water molecules increases. As the cholesterol concentration increased, the phase transition interval increased. The results also showed that the values of Prodan’s three wavelength generalized polarization are always higher than the values of Laurdan’s two wavelength generalized polarization.
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Preparation and characterization of quatsomes
Havlíčková, Anna ; Szabová, Jana (referee) ; Mravec, Filip (advisor)
This bachelor thesis deals with preparing and characterizing quatsomes and similar vesicular systems. The preparation consisted of weighing an equimolar amount of sterol and surfactant, hydration with deionized water, and subsequent sonication with an ultrasonic probe with an energy of 5, 10 and 15 kJ. In this work, two types of quatsomes were prepared, the first contained equimolar amounts of cholesterol and cetyltrimethylammonium bromide (CTAB), and the second consisted of cholesterol carbethopendecinium bromide (Septonex). The optimal dispersion energy of 10 kJ was selected for both types based on turbidity measurements, visual observation and dynamic and electrophoretic light scattering analysis. Furthermore, the observed properties were found to be constant from day 7 after sonication. In addition to quatsomes, similar vesicles were prepared, which contained a surfactant in the form of a sulfate salt. Once again, two types were prepared, the first containing sodium dodecyl sulfate (SDS) and cholesterol, the second sodium tetradecyl sulfate (STS) and cholesterol. Based on the same measurements as for quatsomes, optimal dispersion energy of 10 kJ was selected. Furthermore, mixtures with different ratios of cholesterol and a given surfactant were prepared, in which the effect of cholesterol addition was monitored. The analysis of these mixtures was performed by the same methods as the analysis of quatsomes.
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Cross-correlation of mechanical properties of hydrogels on micro/macro-scale studied by atomic force microscopy and oscillation rheometry
Kuzník, Pavel ; Szabová, Jana (referee) ; Smilek, Jiří (advisor)
This bachelor thesis focuses on measurement of mechanical properties of hydrogels on local and macroscopic level by atomic force microscopy (AFM) and oscillation rheometry. Both techniques allows measurement of hydrogel in hydrated state which provides native state of measured samples and prevents them from inserting artefacts into measurements made by AFM, which could negatively change measured values. AFM has more measuring modes, but for measurement in this bachelor thesis was used tapping mode called Contact mode force mapping. The largest part of this work is concentrated on measurement of agarose hydrogel, which pertains to category of physical hydrogels, concretely concentration line and time dependency (syneresis of hydrogel) were measured by both techniques. Suitability of AFM for measuring of mechanical properties of hydrogels was tested on other hydrogel samples with different type of crosslinking. Hydrogel based on sodium alginate crosslinked by calcium ionts (Ca2+) was tested. Furthermore were measured two chemical gels including polyethylenglycol (PEG) hydrogel and organogel of ethylene propylene-diene monomer (EPDM). Measurement of PEG hydrogel included time dependency due to its swelling and absorption behaviour, which led into dissolving of PEG hydrogel. EPDM organogel is not dissolving in water, so it was measured as a standard for AFM measurements. In addition to Young’s modulus as a base parameter for measurement of hydrogels in swollen state, was adhesion and work of adhesion tested in case of EPDM gels.
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Preparation and characterization of quatsomes
Havlíčková, Anna ; Szabová, Jana (referee) ; Mravec, Filip (advisor)
This bachelor thesis deals with preparing and characterizing quatsomes and similar vesicular systems. The preparation consisted of weighing an equimolar amount of sterol and surfactant, hydration with deionized water, and subsequent sonication with an ultrasonic probe with an energy of 5, 10 and 15 kJ. In this work, two types of quatsomes were prepared, the first contained equimolar amounts of cholesterol and cetyltrimethylammonium bromide (CTAB), and the second consisted of cholesterol carbethopendecinium bromide (Septonex). The optimal dispersion energy of 10 kJ was selected for both types based on turbidity measurements, visual observation and dynamic and electrophoretic light scattering analysis. Furthermore, the observed properties were found to be constant from day 7 after sonication. In addition to quatsomes, similar vesicles were prepared, which contained a surfactant in the form of a sulfate salt. Once again, two types were prepared, the first containing sodium dodecyl sulfate (SDS) and cholesterol, the second sodium tetradecyl sulfate (STS) and cholesterol. Based on the same measurements as for quatsomes, optimal dispersion energy of 10 kJ was selected. Furthermore, mixtures with different ratios of cholesterol and a given surfactant were prepared, in which the effect of cholesterol addition was monitored. The analysis of these mixtures was performed by the same methods as the analysis of quatsomes.
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Study of the hydration shell of vesicular systems based on ionic amphiphilic pairs
Rašticová, Barbora ; Szabová, Jana (referee) ; Mravec, Filip (advisor)
This bachelor thesis deals with the study of hydration shell of positively charged vesicular systems. The aim of the work was to monitor the hydration shell and to find out the amount of water molecules in the environment at different conditions of the membrane. Furthermore, a comparison of two selected fluorescent probes were studied. Positively charged vesicular systems composed of two types of surfactants were used, namely negatively charged SDS and positively charged CTAB. The two-chain positively charged surfactant was also added, resulting a positively charged vesicular systems. Three different concentrations of cholesterol were selected for the study and added to the system, namely 20, 40 and 60 mol. %. The study was performed by measuring the fluorescent emission as a function of temperature. The temperature range was from 10 to 80 °C. As a fluorescent probe Laurdan and Prodan were selected. For evaluation the method of generalized polarization was used. Due to its structure, Laurdan is mainly found in the membrane environment, so the method of two-wavelength generalized polarization, which includes fluorescence contributions only from the membrane, was sufficient for its evaluation. Compared to Laurdan, Prodan has a shorter hydrocarbon chain, so its distribution is not only in the membrane but also in the aqueous environment. Therefore, the method of three-wavelength generalized polarization, which also includes the contribution of fluorescence from the aqueous environment was used. The results showed that the behaviour of both probes is very similar. In all systems, the values of generalized polarization decreased with increasing temperature. Thus, at low temperatures, the membrane is in a solid ordered phase. With increasing temperature, it transforms into a liquid disordered phase. Thus, with increasing temperature, the number of water molecules increases. As the cholesterol concentration increased, the phase transition interval increased. The results also showed that the values of Prodan’s three wavelength generalized polarization are always higher than the values of Laurdan’s two wavelength generalized polarization.
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The complicated evolution of methionine adenosyltransferase in euglenids and eukaryotes in general
Szabová, Jana
Many eukaryotic genes do not follow vertical inheritance pattern. In the present work, we have chosen as a model the gene for methionine adenosyltransferase (MAT), in which we have decided to examine in detail the evolutionary history. MAT is a ubiquitous essential enzyme that, in eukaryotes, occurs in two relatively divergent paralogs: MAT and MATX. Both paralogs have punctate distributions across the tree of eukaryotes and, except for a few cases, they are mutually exclusive. This points to the complicated evolutionary history of this gene couple, which may be caused by either differential loss of old paralogs or the spread of one of these paralogs by horizontal gene transfer (HGT). We have focused on the evolution of this enzyme particularly within one of the best-known groups of flagellates, the euglenids, because it was hypothesized that MATX evolved in photosynthetic euglenids before it spread to other lineages. We gained 26 new sequences from 23 euglenid lineages and one prasinophyte alga Pyramimonas parkeae. MATX was found only in photoautotrophic euglenids. Both, mixotroph Rapaza viridis and the prasinophyte alga Pyramimonas parkeae, the closest known relative of the euglenid plastid ancestor, only displayed the MAT paralog. In contrast, both paralogues were found in two euglenid species...
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Preparation and characterization of complex liposomal for drug delivery systems
Szabová, Jana ; Pekař, Miloslav (referee) ; Mravec, Filip (advisor)
This diploma thesis deals with the preparation and characterization of stealth liposomes and their combination with trimethylchitosan (TMC). This complex could find application in the field of inhalation administration. Stealth liposomes were prepared from neutral phophatidylcholine, negatively charged fosfatidic acid and polyethyleneglycol bounded to phosphatidylethanolamine. We have managed to prepare stealth liposomes with suitable properties that should guarantee passive targeting without evocation an immune response, despite the content of the negative component. We also found a suitable method of preparation for stealth liposome–TMC complex, where the change of size and zeta potential confirmed the non–covalent bound between two components despite the content of the polyethyleneglycol.
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