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Study of barrier and transport properties of polyelectrolytes using diffusion techniques in hydrogels
Valentová, Kristýna ; Kalina, Michal (referee) ; Smilek, Jiří (advisor)
This diploma thesis was focused on study of barrier and transport properties of selected polyelectrolytes in hydrogel matrices by using diffusion techniques. The study of these properties was performed in horizontal diffusion cells where is observed the change in diffusion probe concentration over time. Diffusion experiments were performed on an agarose hydrogel with the addition of alginate, hyaluronic acid, polystyrene sulfonate, humic acids and as a model probe rhodamine 6G was used. Important parts of this thesis are also the methods which characterize the substances and hydrogel matrices such as rheology and potentiometric titration. The main aim of this diploma thesis was to investigate the effect of interactions between passing model dye (rhodamine 6G) and the appropriate gel (agarose + polyelectrolyte) on the fundamental diffusion parameters (effective diffusion coefficient, lag time, etc.).
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Microviscosity probes in study of aggregation in a biopolymer-surfactant system.
Vašíčková, Kamila ; Vala, Martin (referee) ; Mravec, Filip (advisor)
The effect of cationic surfactant concentration and ionic strength on anisotropy of fluorescence of probes diphenylhexatrien and fluorescein has been investigated in the system of cationic surfactant and in the system of cationic surfactant and hyaluronan. The investigation has been done by fluorescence emission spectroscopy. Obtained anisotropy gives information about microviscosity of investigated systems. Subsequently the system of cationic surfactant and hyaluronan has been investigated by 9-(2-carboxy-2cyanovinyl)julolidine, 4-(dicyanovinyl)julolidine and 1,3-bispyrenylpropane probes. The information about the microviscosity of the system gives the integral under the emission curve of 9-(2-carboxy2-cyanovinyl)julolidine and 4-(dicyanovinyl)julolidine and the ratio between excimer and monomer of 1,3-bispyrenylpropane. It has been discovered that the ionic strength influences the anisotropy of diphenylhexatrien and fluorescein only in the fist addition of salt (concentration 0,025 mol dm-3) and that addition of hyaluronan influences the anisotropy of diphenylhexatrien and fluorescein only in samples without addition of salt. Results of measurment with 9-(2-carboxy2-cyanovinyl)julolidine and 4(dicyanovinyl)julolidine describe the formation of aggregates of catinoc surfactant with hyaluronan and characterize these aggregates from the point of microviscosity.
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Influence of concentration of surfactant component and temperature on interactions between hyaluronan and katanionic vesicular systems
Janáková, Kristýna ; Jugl, Adam (referee) ; Krouská, Jitka (advisor)
The influence of various concentrations of surfactant component and various temperatures on interactions of hyaluronan with catanionic vesicular systems were examined using isothermal titration calorimetry. The measurements were performed at two different concentrations of surfactant component and three temperature values. The reason for studying the interactions was to explore the possibility of these systems serving as carriers of drugs in the future. Catanionic vesicular systems consisted of a cationic surfactant CTAB, an anionic surfactant SDS and of a positively charged two-chain surfactant DODAC. The solution of negatively charged hyaluronan with concentration of 0,5 mM was used for all measurements.
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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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Phase-separated systems biopolymer-lipid
Kubalová, Barbora ; Pekař, Miloslav (referee) ; Mravec, Filip (advisor)
This diploma thesis deals with experimental study of interaction based on polymer-lipid system. The main goal was to investigate interaction leading to phase separation. Three anionic polyelectrolytes were selected for this purpose: sodium hyaluronate, sodium chondroitin-6-sulfate and sodium poly(4-styrenesulfonate). The liposomes were formulated by sonication of lipid – cationic 1,2-dipalmitoyl-3-trimethylamonium-propane (chloride salt) and zwitterionic 1,2-dipalmitoyl-sn-glycero-phosphocholine. It was found that the phase separation occured at specific ratio of DPTAP and selected polymer. It was also explored that the strong electrostatic interaction which leads to the phase separation can be weaken by increasing the ionic strength in the sample. As we aspected the systems contain the hydrophobic domain and therefore these are able to incorporate hydrophobic substances in their structure.
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Hyaluronan for targeted drug delivery
Ureš, Tomáš ; Vávrová, Milada (referee) ; Pekař, Miloslav (advisor)
Hyaluronic acid (hyaluronan, HA) is a linear polysaccharide formed from disacharide units containing N-acetyl-D-glucosamine and glucuronic acid. HA is present in almost all biological fluids and tissues. In many cancer cells there is an upregulation of CD44, a receptor that binds HA. The receptor CD44 collocates hyaluronan in the special way. The bioconjugates built-up from the cytotoxic substances and hyaluronan are called prodrugs. The prodrugs can be used for targeted drug delivery system. Their main advantage is there is no need to medicine so high doses of pharmaceuticals and their adverse side effects are minimized. Hyaluronan can be used as well as the intra-articulation injection by osteoarthritis. HA is also used as the nutrition of joints, by treatment for diverse dermatic lesions, the repair of scars and it can be the ingredient of eye drops and nasal sprays. The cosmetic manufactures add HA into anti-wrinkle creams and anti-aging care.
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Effect of metal ions on the rheological behaviour of polyelectrolyte solutions
Lišková, Kateřina ; Běťák, Jiří (referee) ; Janeček, Jiří (advisor)
This diploma thesis is focused on two parts. The first one deals with rheological behavior of sodium carboxymethylcellulose (CMC-Na) solutions in the presence of sodium and calcium ions. The solutions of various concentrations were prepared by solubilization in aqueous solutions of NaCl or CaCl2. The effect of monovalent and bivalent ions on apparent viscosity and viscoelastic properties of these solutions was studied. It was found that in the case of low concentrations of CMC-Na in the sample (up to 0.5% w/w) the elastic character increases. At the same time the stiffness of the sample is higher with higher concentration of calcium ion in the solution. This increase might indicate the formation of gel network. On the other hand the viscosity of these solutions decreases with higher concentration of calcium ions. In case of solutions with concentration higher than 1.5% w/w changes of viscosity did not happen by influence of addition ions. Rheological behavior was compared also with solutions prepared without adding an electrolyte as well as with acid form of carboxymethylcellulose (CMC-H). In terms of second part the molecular dynamic simulations of hyaluronan tetramer both sodium and calcium in aqueous medium were performed. Structure and arrangement of water molecules in the surrounding of hyaluronan chain were studied. Structure was described by formalism of radial distribution functions. In the case of system containing sodium ions only, the obtained results are in accordance with earlier published data. Presence of calcium ions does not cause qualitative changes during the radial distribution functions in comparison with the system with sodium ions.
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Temperature dependence of carrageenan and hyaluronan solutions
Poledňáková, Halina ; Smilek, Jiří (referee) ; Hurčíková, Andrea (advisor)
This diploma thesis focuses on the study of temperature dependence of -carrageen, hyaluronan of low molecular weight (250–450 kDa) and hyaluronan of high molecular weight (1 500–1 750 kDa) in aqueous solutions. The description of temperature depending changes in properties of these substance is based on rheological method. This work concentrates on the characterization of viscoelasticity through measurement of the storage (elastic) and loss (viscous) modulus using -carrageen and hyaluronan solutions of different molecular weights and different concentrations depending on temperature (20–50 °C, alternatively, in carrageen, 20–80 °C). The temperature dependence was further measured using an uncommon technique called high resolution ultrasonic spectroscopy (HR-US) which measured relative velocity of selected concentrations of -carrageen and hyaluronan of high molecular weight depending on the temperature of heating and cooling (20–80 °C). The measurements of temperature dependence were carried out for varied oscillation frequencies of rheometer sensor/frequency of ultrasonic waves. Knowledge of temperature dependence of the investigated substances may be applied in drug chemistry, primarily with respect to degradation due to high temperatures. The measured data gives information about sol-gel temperature and gel-sol temperature of carrageen.
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Interaction Between Hyaluronan and Amphiphilic Molecules
Venerová, Tereza ; Burget, Ladislav (referee) ; Čeppan, Michal (referee) ; Pekař, Miloslav (advisor)
This work is focused on interaction between hyaluronan (Hya) and amphiphilic molecules. Using fluorescent probes method were carried out screening of the interaction of various surfactants with Hya. For further examination was chosen cetyltrimethylammonium bromide (CTAB). Interactions in this system have also been studied using fluorescence correlation spectroscopy (FCS), and additionally were performed initial tests of the cytotoxicity of the system. As an alternative CTAB were also used hydrophobically modified amino acids. Results showed their self-aggregation, but their interactions with hylauronanem was not as strong as with CTAB. The interaction of gel systems Hya-CTAB have also been studied, and was found to contain a hydrophobic domain capable solubilize hydrophobic substance. Thermogravimetric have been established that are able to contain up to 98% wt. water and rheologically were characterized their mechanical properties. These are tunable due to molecular weight (MW) of the hyaluronate. With increasing value of MW increases mechanical strength of the gel and decreases its fluidity.
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Using diffusion techniques in the study of hydrogels
Holubová, Anna ; Žitňan, Michal (referee) ; Mravec, Filip (advisor)
Properties of colloidal systems, especially hydrogels, were studied using the method of fluorescence correlation spectroscopy (FCS). Hydrogels were prepared based on hyaluronan and cationic surfactant CTAB interactions. The proposed hydrophilic fluorescent probe, suitable for the study of phase-separated hydrogels in polymer-surfactant systems, was chosen ATTO 488 due to the suppression of triplet state. As a hydrophobic probe was chosen Nile Red. Individually were examined micellar systems of 10 mM CTAB and 0,5% sodium hyaluronate in water and 0,15 M NaCl in different concentrations of selected fluorescent probes. Subsequently the hydrogel systems were studied. The results showed that the measurement of hydrogels by this method is realizable. Short lifetimes were created by a complex probe and CTAB causing quenching and low levels of diffusion coefficients characterize the viscous environment of study system.
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