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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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Use of microcalorimetry in the study of hydration of biopolymers
Bola, Tomáš ; Smilek, Jiří (referee) ; Krouská, Jitka (advisor)
This master thesis deals with the using of microcalorimetry in the study of hydration of biopolymers. Lactose has been selected together with the other biopolymers although it is not among biopolymers but disaccharides. Selected biopolymers are alginate, dextrane, chitosan and hyaluronan of two molecular weights. Lactose has been selected for these purposes mainly because it is a model example to determine whether or not the reaction to moisture between the other samples and the saturated salt solution occurs. The biopolymer hydration study, as opposed to the commonly used perfusion calorimetry method using the possibility of measuring with adjustable moisture has been used an isothermal microcalorimetry method where at two constant temperatures the reaction of the sample to the different moisture released by the saturated salt solution was monitored.
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Influencing of molecular mass of hyaluronic acid by fermentation process
Wikarská, Monika ; Jílková, Jana (referee) ; Velebný, Vladimír (advisor)
The biological function of hyaluronic acid (HA) – the polysaccharide, which consists of repeating units of N-actylglucosamine and glucuronic acid – is extremely broad and often contradictory, depending on its molecular weight (MW). The bacterial production provides HA of high molecular weight and purity. The objective of this thesis is to control the molecular weight of produced HA by the addition of hyaluronidases during the process of fermentation, resulting in reduction of viscosity of the medium followed by increase of yield. Hyaluronic acid was prepared by batch fermentation of the microorganism Streptococcus equi subsp. zooepidemicus. During the process of fermentation, the enzyme hyaluronate 4-glycanohydrolase (BTH) at various concentrations and different times of cultivation was added to bioreactors. The HA yield, the molecular weight and the polydispersity by the SEC-MALLS were monitored, together with the residual glucose concentration and the dynamic viscosity of the production medium. The formation of low and medium molecular weight HA was achieved. The addition of 10 U (BTH) / g (HA) had no significant effect on the molecular weight and therefore the HA function, but the corresponding drop of viscosity was noteworthy for the simplification of the product purification. Potential increase in HA yield was not confirmed because of the very low concentration of residual glucose and the method of precipitating low and medium MW HA.
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Viscometric study of L-Lysine- and 6-aminocaproic acid-hyaluronan systems behavior within the range of low aminoacids concentrations
Šimáčková, Marcela ; Běťák, Jiří (referee) ; Chytil, Martin (advisor)
This bachelor thesis investigates the interaction between high-molecular weight hyaluronic acid (1.75 MDa HA) and amino acids, particularly lysine and 6-aminocaproic acid. The interactions should occur between the carboxyl groups of HA carrying a negative charge and a positive charge located on the nitrogen atom of the protonated amino acids. The presence of these interactions would mean the possibility of establishing bioactive compounds, e.g. drugs, on hyaluronic acid, in which it would act as a targetting carrier. The interactions were examined at low concentrations for both aminoacids, i.e. below 10 mmoldm-3, and for 6-aminocaproic acid also at high aminoacid concentrations, i.e. above 20 mmoldm-3. The presence of interaction was investigated using not only rheology, but also by measuring pH and conductivity. Based on this research, the interactions manifested in terms of a decrease in the system viscosity.
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Microrheology in study of biopolmer colloids.
Hnyluchová, Zuzana ; Sedláček, Petr (referee) ; Mravec, Filip (advisor)
A new method for determining the viscoelastic properties of materials was introduced and investigated. Results of three groups of samples obtained using one particle microrheology method, DLS microrheology method and classical rheology method were compared to be sure of correctness of measurements. As a model system were chosen mixtures of glycerol of different viscosities. In case of samples containing glycerol, results were also compared with tabulated values. Hyaluronan of various molecular weights was used as a biopolymer and polystyrene particles were used for microrheology. It was confirmed, that viscosity values of biopolymer samples obtaining by each method are comparable.
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Hyaluronan nanofibers
Linhartová, Beáta ; Velebný, Vladimír (referee) ; Pekař, Miloslav (advisor)
This bachelor´s thesis deals with the most common methods of producing nanofibres, it presents an overview of these techniques and briefly desribes common models. It shows their advantages and disadvantages and tries to follow the develompent of nanofibres. This theoretical part is followed by an experimental one which describes concrete example of producing nanofibres.
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Rheological study of high-molecular weight hyaluronan-protonated aminoacids interactions
Zeman, Jan ; Běťák, Jiří (referee) ; Chytil, Martin (advisor)
The study deals with interactions of hyaluronic acid with protonized amino acids Lysin and 6-aminocaproic acid. To study the interactions pH-metry, conductance measurement and reometry were used. The mixtures of hyaluronan and the aminoacids of different concentrations were measured and the data were compered with data obtained from measurement of amino acid samples in pure water. Observed interactions occured in the aminoacids concentrations between 0 to 10 mmolxdm3, then the HyA carboxylic groups were fully bonded by amino acids and no more interactions were recognized.
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Polysaccharide-protein gels
Hájovská, Pavla ; Smilek, Jiří (referee) ; Chytil, Martin (advisor)
This bachelor thesis deals with gelation of albumin solutions and mixed solutions of albumin and the high molecular weight hyaluronic acid due to heating. Study was carried out by measuring rheological properties of the solutions, formed gels and gelation process. For the protein samples in water, the effect of concentration, ionic strength and pH were tested. For mixed solutions, the effect of concentration and a composition of the polymeric component were tested. With increasing concentration of the polymeric component, the gel point is shifted towards lower temperature values, with the concentration difference of 2 % (w/v) up to 5°C. The resulting gels exhibit higher values of loss and storage moduli. Similar behavior was observed also in the samples influenced by the ionic strength as, a result of alternation of the electrostatic interactions between the charged groups of the polymer chains and as a result of change of this charge due to the pH reduced below the pI value of the protein.
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Cationic fluorescence probes in a polyanion-surfactant system.
Mondek, Jakub ; Šmejkalová, Daniela (referee) ; Pekař, Miloslav (advisor)
In this bachelor thesis were studied properties of aqueous solutions of hyaluronan and celytrimethylamonnium bromid with help of acridine orange as fluorescence probe. At first, this thesis was focused on interactions of acridine orange and hyaluronan. Emision and excitation spectra of acridine orange were observed. Result of these measurement was bonding of acridine orange dimer to carboxylic group of hyaluronan. Next studied interaction was interaction of cetyltrimethyl amonium bromid with acridine orange – hyaluronan system. Result of these interaction was, that molecules of cationactive surfactant pushed away dimers of acridine orange and took place of dimer of acridine orange on carboxylic group of hyaluronan. Dimer of acridine orange was changed into monomers. The reason why this thesis was focused on study of aqueus solutions of hyaluronan with cationactive surfactant is benefit of hyaluronan – surfactant system in research of transport system for target distribution of drugs.
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Determination of additives in multicomponent electrospinning systems
Gajdová, Barbora ; Petr, Knotek (referee) ; Knotková,, Kateřina (advisor)
This bachelor thesis deals with methods of producing nanofibres from mixture of different polymers. Different methods of preparation and production nanofibres by 4SPIN® are described in theoretical part. Experimental part deals with incorporation of additives into fibred layer. There were four different dyes used in this thesis: brilliant green, erythrosine, riboflavin and eriochrom black. UV – VIS spectrophotometry was used to measure volume of additives in nanofiber layer.
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