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Viscosimetry of hyaluronan-amphiphile systems
Trojan, Martin ; Běťák, Jiří (referee) ; Chytil, Martin (advisor)
This bachelor thesis investigates the interaction between the polysaccharide sodium hyaluronate (HA) and some amphiphilic molecules. As amphiphilic molecules the aminoacids lysine and 6 – aminocaproic acids were chosen. The presence of the carboxylic group on HA and the aminogroup on the aminoacids suggests electrostatic interaction between these two compounds. This supposal offers the possibility to modificate HA and uses it as a new type of a carrier of bioactive compounds, for example medicals. The HA of two molecular weights (1.75MDa and 70kDa) were chosen for the study of the interactions with the aminoacids. Solutions of HA and stock solutions of the aminoacids were prepared for their mutual mixing in the various volume ratios. The solutions and the mixtures were measured in three types of environment: pure water, 0.15M solution of NaCl and in phosphate buffer (PBS) of pH 6. The interactions were investigated by means of reometry. Our results show, the presence of interactions between HA and the aminoacids mainly in the system consisting the 1.75 MDa HA and lysine in water. As a result of the interactions, a decrease in the viscosity of the mixtures comparing to the HA solutions was observed.
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Hyaluronan-albumin system dynamics
Jarábková, Sabína ; Smilek, Jiří (referee) ; Chytil, Martin (advisor)
The bachelor thesis deals with the hyaluronan and albumin system dynamics. In this study was to use these methods: interfacial rheology, tensiometry, method of maximum pressure in the bubble and UV-VIS spectrophotometry. The measurements were used with various concentrations of albumin and a constant concentration of hyaluronan( high molecular and low molecular too) and then conversely. All solutions were measured and the obtained data were compared with the results of BSA in buffer without HA. Solutions were prepared with citrate-phosphate buffer of pH about 4. Were observed interaction between HA and BSA.
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SEC-MALLS study on hyaluronan-albumin interactions
Sereda, Alena ; Kalina, Michal (referee) ; Chytil, Martin (advisor)
This work is focused on interactions of hyaluronan (HA) and bovine serum albumin (BSA). These interactions were studied by SEC-MALLS method, where molar mass, root mean square (rms) radii, hydronamic radius and intrinsic viscosity of particles of the system were defined. Additionally, interactions were examined by measurement of DLS and zeta potential, where hydrodynamic radius and a value of the zeta potential were defined. The interactions were confirmed at any of the used media, but with different efficiency. Furthermore it was found out, that the high ionic strength minimizes the range of the interactions, magnifies the radii of the complexes, their intrinsic viscosity and zeta potential. It was proved that complexes become smaller in their radii and viscosity with growing BSA concentraton.
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Electrolytic properties of hyaluronan solutions
Suchá, Šárka ; Smilek, Jiří (referee) ; Chytil, Martin (advisor)
This batchelor thesis deals with electrolytic properties of hyaluronan in aqueous solutions. In this study measuring of conductance, acid-base and conductrometric titration, and UV-VIS spectroscopy were used. The measuring of conductance was made on the solutions of different concentrations of hyaluronic acid and of different ionic strength. Acid-base titrations were performed in water solution and conductometric titrations were performed in 0,3mmol.dm–3 solution of sodium chloride. UV-VIS spectra of hyaluronic acid were measured in solution with addition of acid, base and in buffer solution. Values of pKa obtained from the above mentioned measurements was between 2,8–6,5.
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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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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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Investigation of Polyelectrolytes Interactions with Cationic Aminogroups-containing Amphiphiles
Zeman, Jan ; Běťák, Jiří (referee) ; Chytil, Martin (advisor)
The study deals with interactions of polyelectrolytes polystyrene sulfonate and hyaluronic acid with nitrogenic amphiphilic substances, represented by lysine and albumine. To study the interactions pH-metry, conductance, viscositic and turbidity measurement, DLS and reometry were used. All mixtures of different concentrations were measured and the data were compered with data obtained from measurement of samples with amphiphilic sumstances without polyelectrolytes. Observed interactions occured in the aminoacid concentrations between 0 to 20 mmoldm-3, then the PSS interaction groups were fully bonded by lysine and no more interactions were recognized. The same behaviour were observed in albumine solutions with concentration under 2 gdm-3.
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Study on interactions of protonated aminoacids with low-molecular weight hyaluronan
Chlumská, Jana ; Kalina, Michal (referee) ; Chytil, Martin (advisor)
This bachelor thesis deals with interactions between hyaluronic acid (HA) of low molecular weight (110-130 kDa) and protonated aminoacids lysine and 6-aminocaproic acid. For investigation of these interactions, methods such as pH-metry, conductance measurement, viscometry and dynamic light scattering were used. The electrostacic interactions between carboxylic group of HA and the aminogroup of the aminoacids are presumed. Proving these interactions would allow us to physically modify HA and further more, using such a system as a carrier of pharmaceuticals. The interactions of protonated lysine with HA were studied in pure water or in the solution of NaCl (c = 15 mmol•dm-3). Interactions of 6-aminocaproic acid were studied only in pure water. Both aminoacids were in the concentration range 0.9-20 mmol•dm-3. The decrease in the viscosity of the solutions indicates the interactions for lysine; for 6-aminocaproic acid the interactions also occured, but not as signifciantly as for the system containing lysine.
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Characterization of hyaluronan interactions with albumin
Valentová, Kristýna ; Kratochvílová, Romana (referee) ; Chytil, Martin (advisor)
This bachelor thesis focuses on the research of physical interactions between hyaluronic acid and a protein albumin. In order to investigate these interactions following methods were used: pH and conductivity measurement, viscosimetry, turbidimetry and rheometry. The interactions were observed in solutions of fixed albumin concentration 1.0 gdm-3 and varying concentrations of hyaluronic acid from 0.1 to 2.0 gdm-3. Results were compared with a solution of hyaluronic acid without the addition of albumin. The results show that there are interactions between hyaluronic acid and albumin solutions, especially for those containing high molecular weight hyaluronic acid. The interactions exhibited a change in viscosity of solutions. We can see a reduction in viscosity after adding albumin to the reference solutions. The reduction is noticeable even in the low molecular weight HA solutions, but is not so significant.
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