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Interactions between hyaluronan and cetrimide
Adamcová, Zuzana ; Sedláček, Petr (referee) ; Mravec, Filip (advisor)
Interactions between hyaluronan and cationic Cetrimide were studied using fluorescence spectroscopy and turbidimetry in model physiological solution (0,15 M NaCl) and water. Results obtained in water showed strong electrostatic interactions before reaching CMC of the surfactant, which were screened in presence of salt due to high ionic strenght of the solution. Behavior of Cetrimide-hyaluronan systems was compared with the pure TTAB in equivalent system. It was found, that changes in Cetrimide-HA system occure at lower concentrations of the surfactant than in TTAB-HA system. This was probably caused by presence of small amount of CTAB in Cetrimide.
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Complexes of aminoclays and polyelectrolytes
Málková, Ivana ; Pekař, Miloslav (referee) ; Mravec, Filip (advisor)
This thesis deals with the preparation of aminoclay and its products resulting from the interaction of aminoclay with natural polyelectrolyte. The theoretical part deals with the study of aminoclay and selected polyeletrolytes, which were used in the experimental part of the thesis. Potassium pectate, sodium alginate and sodium hyaluronate were chosen as polyelectrolytes. The aim was to let these two groups of compounds interact and to observe the formation of an aminoclay polyelectrolyte complex, taking form of a gel or a precipitate when appropriate concentrations were chosen. The resulting products were characterized in appearance and pH of the products was measured.
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Influence of conditions on hydrogel preparation
Heger, Richard ; Kalina, Michal (referee) ; Mravec, Filip (advisor)
This work is focused on testing the influence of conditions, more precisely pH, during the creation of hydrogels that were prepared through the hydration of powdery mixtures, by another name solid-mixture way. The hydrogel system was made from a polyelectrolyte, more accurately sodium hyaluronate and a cationic surfactant, CTAB. The influence of pH was studied through observation and rheology. For measuring purposes, the hyaluronan with the molecular weight of 600-800 kDa was used. The system was examined via a series of buffers with the pH of 3,5-11. The gels were dyed by Sudan III for better observability and description. It was found that the best way of adding an active substance was by adding a dye directly into a powdery mixture. The observed properties of the gels didn’t change even after the gels were modified to the ionic strength of a physiological saline solution (0,15 M).
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Mixed lipids and their interaction with biopolymers
Cigánková, Hana ; Smilek, Jiří (referee) ; Mravec, Filip (advisor)
This thesis focuses on the study of interactions between hyaluronan and lipid DOTAP and its mixtures with DPPC in water. First, the aggregation behavior of the lipid itself and its mixtures was measured, afterwards the influence of hyaluronan in different concentration was studied. Further the fluorescence anisotropy of fluorescence probe DPH in these mixtures and influence of cholesterol was measured. These properties were investigated by fluorescence spectoscopy using pyrene and DPH as fluorescence probes. The measurements revealed that the addition of hyaluronan has observable influence on the aggregation behavior of the lipid DOTAP and its mixtures with DPPC and that cholesterol influences liposomes fluidity.
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Preparation and characterization of hydrogels based on cationic biopolymer
Tesařová, Barbora ; Mravec, Filip (referee) ; Smilek, Jiří (advisor)
Presented thesis deals with the preparation and characterization of hydrogels based on positively-charged biopolymer and negatively-charged tenside. As an appropriate representative of positively-charged polymer was chosen chitosan, because of his biocompatibility and biodegrability, and N,N,N-trimethylchitosan, which was synthetised from chitosan in this diploma thesis. The final product of synthesis was characterised by SEC-MALS, elemental analysis, infrared spectroscopy and nuclear magnetic rezonation. Interactions between these polymers and representatives of negatively-charged tensides, which are sodium dodecylsuphate and sodium tetradecylsulphate, were investigated. The main method used in this thesis was rheology, through it were investigated prepared hydrogels based on chitosan and tensides and also prepared microgels based on N,N,N-trimethylchitosan and tensides. The interactions between polymers and tensides have been proved.
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Analytical methods for hyaluronan
Černá, Lucie ; Mravec, Filip (referee) ; Pekař, Miloslav (advisor)
This thesis deals with of simple methods for determining the concentration of hyaluronan in aqueous solution and compares the performance of each selected methods such as UV -VIS spectroscopy, IR spectroscopy and the method of determination by alcian blue. These methods were chosen for their simplicity and low cost of the assay. As the most reliable of these three methods, seems to be the method of IR spectroscopy. Determination of the concentration of HA by this method is relatively accurate at concentrations above 0.4 % in deionized water. The method of UV-VIS spectroscopy is based on a linear calibration curve determination, but no characteristic peak was detected, which means that this determination could be influenced by other components of the aqueous solution. Weak ionic strength and molecular weight of HA does not affect the determination. In the method with alcian blue, the results were quite unsatisfactory and does not correspond with the literature. Therefore, this method is not applicable in this form for determining the concentration of HA. Another option for determining the concentration of the HA is ELISA method. These are commercially produced kits suitable for determining low concentrations in low volumes. Its price is higher than the above- mentioned methods.
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Surfactant organogels as delivery systems for medical and cosmetic oils
Koláčková, Petra ; Mravec, Filip (referee) ; Pekař, Miloslav (advisor)
The aim of this thesis was to investigate the possible using of surfactant organogels in the cosmetic industry. Mainly, we focused on the ability of sugar surfactants to bind with medical (cosmetic) oil. With further heating, we observed transformation to the organogels. During the preparation of sugar surfactants, we decided to use the transesterification method. Another target was to verify functionality of this method and then proposed modifications to this process. Using Nuclear Magnetic Resonance, we checked the chemical structure of our sugar-based surfactants.
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Complexes of aminoclay and selected organic compounds
Dušek, Jakub ; Pekař, Miloslav (referee) ; Mravec, Filip (advisor)
This paper describes the preparation of aminoclay and complexes of aminoclay with selected bioactive substances. The theoretical part deals with the study of aminoclay and substances suitable for complexes and suitable modification of preparation these complexes. Experimental part of this paper consists of preparation of aminoclay complexes and verification of their formation. In order to verify the formation of the complex by binding of bioactive compounds to the free amino groups of aminoclay were used methods FT-IR (Fourier transform infrared spectroscopy) and XRD (X-ray diffraction). For selected substances, binding to the aminoclay would improve their properties, which was the main motivation for the research. The resulting complexes could be more effective by replacing existing substances used in the pharmaceutical industry and biomedical applications.
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Phase separation in the system of aminoclay-biopolymer
Plotěná, Michaela ; Pekař, Miloslav (referee) ; Mravec, Filip (advisor)
The aim of this diploma thesis was to study the structure and to evaluate the properties of the hydrogel prepared by the interaction of the aminolclay with the biopolymer. Representatives of the biopolymers were selected from low to medium molecular weight sodium hyaluronate and sodium polystyrenesulfonate. On the basis of the experiments carried out, it was found that phase separation takes place only when the aminolclay interacts with medium molecular weight hyaluronan (MMW). In the experimental part, analyzes of this sample were carried out in order to determine the formation of phase-separated hydrogel by influencing the solution by ionic strength, investigation of hydrogel extinction in various organic solvents, stability of hydrogel under extreme temperature conditions, the effect of storage on its degradation, etc. Viscoelastic properties were experimentally proven by rheology and thermal analysis detected binding water. Inhibition of microorganisms was confirmed by antibacterial diffusion assays. All experiments were carried out for the use of the Aj-HyA hydrogel (MMW) in the field of medical applications, specifically for the modern method of wet wound healing of the skin.
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Optimizing the determination of distribution of surfactant at phase separation in polymer-surfactant system
Sátorová, Kateřina ; Pekař, Miloslav (referee) ; Mravec, Filip (advisor)
This diploma thesis is focused on the determination of distribution a surfactant at phase separation in polymer-surfactant system. Sodium hyaluronate of three molecular weights was chosen as a polymer, CTAB was used as a surfactant. The experiments were performed in an environment of 0,15 M NaCl. The measurement of the CTAB concentration in samples was based on the formation of coloured complexes of CTAB and picric acid in chloroform. UV-VIS spectroscopy was used for the detection of these complexes. The content of CTAB was determined in four gels of different composition (2% Hya + 200 mM CTAB, 2 % Hya + 50 mM CTAB, 0,5 % Hya + 200 mM CTAB, 0,5 % Hya + 50 mM CTAB). All gels were gradually washed five times with 0,15 M NaCl. The content of CTAB was determined for newly prepared gels and for gels after 2 and 4 months since the preparation. Initial concentrations of CTAB and hyaluronan have greater influence on the distribution of CTAB after phase separation, than the molecular weight of hyaluronan. The content of CTAB in newly prepared gels and after 4 months since preparation is very similar and demonstrates the stability of the system.
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