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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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Dialysis study of hyaluronan-surfactant interactions
Šejnohová, Michaela ; Venerová, Tereza (referee) ; Pekař, Miloslav (advisor)
This diploma thesis is concentrated on the interactions between polyelectrolyte (hyaluronan) and cationic surfactant (CTAB). The experiments were performed in an aqueous solution and in an environment of physiological ionic strength (0,15mmoldm-3 NaCl). The determination of the surfactant concentration in solutions was based on the formation of colored complexes of CTAB and picric acid in chloroform. The concentrations of surfactant were measured by UV-VIS spectroscopy. The stability of CTAB+HyA was examined by a dialysis method. The results showed that, regardless of the environment, the presence of HyA in solution reduces the number of free molecules of CTAB which can be determined in the sample. It has been proved that there is an interaction between HyA and surfactant and that CTAB has greater affinity for HyA then for the picric acid. The stability of CTAB+HyA was determined by dialysis of 120 hours. After that time, the concentrations of the retentate and permeate were settled. The results showed that in the membrane remains a certain amount of CTAB bounded to hyaluronan. The system can be suitable for the preparation of targeted carriers of biologically active substances.
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Influence of molecular weight of polymers on phase-separated hydrogels
Kolomá, Nikola ; Smilek, Jiří (referee) ; Mravec, Filip (advisor)
This work is focused on study of individual systems of hyaluronan mixtures. All mixtures of hyaluronans they were ready at molecular weights of 15-30 kDa, 80-150 kDa, or 1500-1750 kDa. These individual molecular weights were combined in different ratios most often in ratios of 70:30, 50:50 and 30:70. Septonex surfactant was used for all mixed samples and CTAB was used for last experiment too. At first the gel samples were prepared by a dry route of individual powders with accurately calculated batches. All solutions were prepared wet route with stock of exactly calculated concentration. Physical gels were prepared by combinations of Septonex and hyaluronan with the different molecular weights. In solution formed irregular shapes which we could describe as "marbles" or "beads". After the sample was to stand, the individual „marbles“ of the gel were formed whole mass. Was done too many experiments with physical gels, which has been carried out behavior of mixtures hyaluronans with different molecular weights. All physical and chemical properties were observed by the eye, described and in the and were photographed. Was used hydrophil dye in experiments and served for better visualize comparison samples between themselves. The last experiment was rheological measurement with which is possible characterize viscosity od individual samples.
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Dynamic surface tension in study of hyaluronan-surfactant interactions
Herzog, Milan ; Žídek, Jan (referee) ; Pekař, Miloslav (advisor)
The main task was to characterize interactions between negatively charged biopolymer sodium hyaluronate and two cationic surfactants: cetyltrimethylammonium bromide (CTAB) and tetradecyltrimethylammonium bromide (TTAB). Interactions between sodium hyaluronate and these surfactants are based on their different charge and can be detected by changes of surface tension. The influence of constant addition of sodium hyaluronate (MW = 90 and 1400 kDa) on interface tension values at increasing bubble lifetime was observed. For this purpose, the maximum bubble pressure method was choosen. The measurements were performed in water and in 0,15 mol•l-1 NaCl solution. The obtained results can be used as for description of dynamic properties of hyaluronate-surfactant systems as, e.g., in targeting drug delivery.
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Effect of crowding agents on DNA-surfactant interaction
Sovová, Šárka ; Hurčíková, Andrea (referee) ; Pekař, Miloslav (advisor)
Tato diplomová práce se zabývá vlivem zaplňovacích činidel na interakce v systému DNA-tenzid. DNA o velikosti 4017 párů bází byla připravena polymerázovou řetězovou reakcí, jako templát byl použit plasmid pSB-E1g. Polyetylen glykol (PEG) byl použit jako zaplňovací činidlo a jeho vliv na DNA-tenzid interakce byl zkoumán experimenty založenými na fluorescenci a gelové elektroforéze. Také byl studován vliv iontové síly za použití NaBr na interakce DNA-tenzid za použití zaplňovacího činidla. Data byla vyhodnocena a evaluována v této práci. V úvahu byl brán i možný vliv polyetylen glykolu na kritickou micelarní koncentraci (CMC) tenzidu, bylo provedeno měření CMC pomocí ultrazvuku s vysokým rozlišením, avšak nebyl zjištěn žádný značný vliv zaplňovacího činidla na CMC tenzidu. Část této práce bude zahrnuta v publikaci s anglickým názvem Combined role of macromolecular crowding and cationic surfactant in efficient DNA condensation.
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Preparation and application of physical hyaluronan gel
Kovářová, Lenka ; Krouská, Jitka (referee) ; Venerová, Tereza (advisor)
Bachelor's work is concerning by research in physical hyaluronan gel area. Research is focusing on its preparation, especially by interaction of hyaluronan (HyA) solution with opposite charged surfactant in physiological solution (0,15 M NaCl). In the first part of work I found out influence of molecular weight, concentration of original hyaluronan solution and the ratio of binding sites on hyaluronan chain and surfactant on amount of solids in gel, expressed in percent. Finally we can say, that this value is not influenced by molecular weight of HyA neither relation of binding sides. On the other side, concentration of original HyA solution has significant influence on amount of solids in gel. There was also researched process of gel swelling, where was set amount of water (in percent) able to take dried gel back. Analogical conclusion has been reached like amount of solids in gel. In other part were researched influence of hyaluronan molecular weight and the ratio of binding sites on hyaluronan chain and surfactant on formation of excimers and spectrum change by fluorescence spectroscopy. Pyrene, 1,3-bis(pyren-1-yl)propane (P3P) and prodan were used as fluorescence probes. Excimer emission showed at P3P, while there was no growth of intensity at 470 nm for pyrene. It was found that molecular weight does not affect the value of the ratio of excimer and monomer probe P3P, or the ratio of the first and third peaks of pyrene. The ratio of binding sites HyA and surfactant influence only relation of excimer to monomer (P3P probe), while influence to relation 1:3 hasn't been noticed for pyrene. I have compared spectrum of developed gel for prodan probe, relevant solid and swelled gel by return. It also served for drying and swelling process visualisation.
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Interaction of hyaluronan with surfactant CAE
Trtek, Jan ; Pekař, Miloslav (referee) ; Hurčíková, Andrea (advisor)
The diploma thesis is focused on the study of interactions between hyaluronan of various molecular weights with CAE surfactant. This surfactant does not have the exact composition and there is not known their molecular weight. One of the main parameters needed to describe the interactions between surfactant and hyaluronan, there is the determination of critical micellar concentration. The value of critical micellar concentration of CAE is not known yet. All measurements were made for solutions in aqueous solution and 0.15 M NaCl. The determination of the molecular weight of this surfactant was performed by the technique SEC-MALS-dRI. High resolution ultrasonic spectroscopy was chosen to determine the critical micellar concentration and tensiometry was chosen as a complementary method. The interactions of CAE surfactant with polysaccharide of hyaluronan were showed by high resolution ultrasonic spectroscopy and densitometry. Compressibility was calculated from ultrasonic velocity and density.
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Influence of the preparing of a biopolymer-surfactant system on its aggregation behavior.
Pilgrová, Tereza ; Sedláček, Petr (referee) ; Pekař, Miloslav (advisor)
To study the effect of the method of preparation of biopolymer-surfactant on the aggregation properties several experiments were designed. Closer investigation was made on native hyaluronan-cetyltrimethylammonium bromide (CTAB) system. The system has been studied in the phosphate buffer in aqueous and saline solutions. The effect of the order of substances addition in the samples, the influence of different methods of preparation of certain concentrations of the solutions or the effect of dissolving powdered biopolymer and surfactant on the contrary, the resulting system were investigated. Fluorescence intensity was measured for all prepared samples and its changes were investigated. Pyrene and Nile red were used as fluorescent probes. Some samples were also measured by tensiometer. Measurement of surface tension was based on the method of divorcing the ring from the surface. It was found that the order of the mixing of solutions has a significant effect on the aggregation properties of the system and its appearance. Further effects were detected on the prepared samples by dissolving powdered biopolymer surfactants and vice versa, and environmental influences of the polarity of the system. It was found that sodium chloride abolished the effects of interactions in the system. Effect of method of preparation of certain concentration of CTAB in phosphate buffer is reflected only slightly.
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Phase separation in dilute solutions of polymers and surfactants
Klementová, Tereza ; Krouská, Jitka (referee) ; Mravec, Filip (advisor)
This bachelor's thesis deals with conditions of phase separation in system of polyelectrolyte (sodium hyaluronate) and cationic surfactant (cetyltrimethylammonium bromide). Separated phase was studied by fluorescence measurement with Nile red as a fluorescence probe and there were also specified rheological properties using flow tests and frequency oscillatory tests. Behaviour of separated microgel was also observed in solution of NaCl.
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Study of physical gels with hydrophobic domains
Kovářová, Lenka ; Márová, Ivana (referee) ; Mravec, Filip (advisor)
The thesis is focused on physical hyaluronan gels. The object of study is the interaction of hyaluronan (HyA) with oppositely charged surfactants in physiologic solution (0.15 M NaCl), leading to the formation of gel. In the first part of work have been determined the solids´ contents (X) in gels and their supernatants in percentage and their correlation with molecular weight concentration of original HyA solution and the ratio of binding sites on hyaluronan chain and surfactant CTAB. To conclude, decrease in HyA concentration results in higher values of X and vice versa. On the other hand, increase in the value of X with increasing molecular weight of HyA is not so significant. Analogous conclusions have been made for supernatants and the amount of solids in gel. Drying process has been recorded by drying curves. Swelling process has been used for the characterization of gels. The percentage of water that can be absorbed by dried gel, was determined. The results are in agreement with the measurements of solids´ content in gels. In the next part, the correlation between rheological properties of gels and HyA concentration, HyA molecular weight and concentration of CTAB have been studied by the oscillation and flow tests. The samples with the highest molecular weight and concentration have the most viscoelastic character. The flow test confirmed the assumed pseudoplastic behavior of gels. A very interesting trend arose while comparing HyA concentrations and viscosity in stock solutions and gels. Whereas in stock solution viscosity (at low shear rate) is lower with increasing of HyA concentration, the situation was exactly the opposite in gels. The results are in agreement with frequency tests and observed character of gels.
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