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Hydrogels hyaluronan-surfactant: phase diagram
Gruberová, Eliška ; Hurčíková, Andrea (referee) ; Pekař, Miloslav (advisor)
This bachelor’s thesis deals with phase separation of the hyaluronan-cationic surfactant system in a model physiological solution of 0,15 M NaCl resulting in gel formation. The most widely used concentrations of hyaluronan and a wide range of surfactant concentrations was used to form the gel. We have investigated under which conditions the greatest amount of compacted gel was produced. It has been found that phase separation occurs over the entire concentration range. The largest amount of gel was formed at the highest concentration of both hyaluronan and surfactant. The results were plotted in well-arranged graphs. A hydrophobic colorant was used to indicate the presence of micellar formations and the results were depicted in a schematic phase diagram.
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Involvement of vibrational spectroscopy in the study on interactions of natural organic matter with model environmental pollutants.
Stehlíková, Kristína ; Enev, Vojtěch (referee) ; Sedláček, Petr (advisor)
The main objective of this diploma thesis was to verify the potential of using advanced infrared spectra processing techniques – specifically the principal component analysis (PCA) – in order to monitor the interaction of natural organic matter with organic pollutants. Natural organic matter was represented by standard IHSS Leonardite humic acid, while the aromatic dyes methylene blue and Rhodamine 6G and the aliphatic substance Septonex were chosen as representatives of organic ions. Their interactions were monitored using Fourier-transform infrared spectroscopy, the use of which for this purpose was verified in my bachelor's thesis. Principal component analysis was finally applied to the obtained infrared spectra of the formed complexes and prepared blank samples, which helped to reveal spectral changes at first glance unrecognizable in the spectra themselves. It was found out that the most likely mechanism of humic acid interaction with aromatic pollutants is a - interaction, while the electrostatic nature of the interaction is assumed for the binding of aliphatic substances.
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Preparation and characterization of magnetic nanoparticles modified by surfactants
Solnička, Ondřej ; Másilko, Jiří (referee) ; Enev, Vojtěch (advisor)
Theme of this bachelors thesis was preparation and characterization of iron(II, III) oxide nanoparticles. Those nanoparticles were modified by surfactants. The surfactants which were used for modifiation were CTAB, TTAB and Septonex. Prepared and modified nanoparticles were taken for characterization by using methods of elemental analysis, thermogravimetry, dynamic light scattering and transmission electron microscopy (TEM). Results from each measurement shows that nanoparticles modified by CTAB had on average 85.9 nm in diameter, TTAB size was on average 108.3 nm and the last nanoparticles with Septonex had 246.6 nm in diameter on average. Prepared modified nanoparticles except the Septonex ones were stable enough to not aggregate. Septonex modified nanoparticles had greater tendenty to aggregate.
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Structural aspects of interaction between humic substances and charged organic xenobiotics
Prisažný, Adam ; Smilek, Jiří (referee) ; Sedláček, Petr (advisor)
This diploma thesis was focused on studying the interaction of humic substances with ionic organic xenobiotics and its structural aspects. The method was chosen from my bachelor thesis, steady-state fluorescence spectroscopy, which is suitable for substances with weak fluorescence. The results showed that the interaction between humic acids and representatives of ionic organic xenobiotics (Septonex) was reflected in fluorescence quenching of humic acids and the shift of emission maximum to lower wavelength, hypsochromic (blue) shift. From the measurement results, we can assume that the interaction that is formed between the aromatic structures in humic acids and Septonex could be -cation interaction.
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New amphiphilic ion pairs for the preparation of vesicular systems
Strnadová, Martina ; Kalina, Michal (referee) ; Mravec, Filip (advisor)
The bachelor thesis is focused on the preparation of the new vesicular systems. The aim of this work is to create the most stable system and find out the most optimal working method for its production. The compared parameters were the energy used for dispersion, the molar percentage of cholesterol added, and the type of double-stranded positively charged surfactant. The whole system consisted of negatively charged surfactant sodium dodecyl sulfate and positively charged surfactant septonex. Each system was compared over time to determine stability based on the size of the particle, zeta potential, and turbidity of the solution. By the method of dynamic light scattering, particle size and polydispersity coefficient were measured. On the other hand, the zeta potential was determined by electrophoretic light scattering. The result of the thesis presents the most suitable parameters of ultrasonic dispersion, the molar proportion of cholesterol, and the use of cationic surfactant. Based on these parameters, it is possible to create a physically stable system for a long period of time, thanks to which such a system can be used in the future for other applications.
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Study of bulk and hydration water in hydrogel systems suitable for medical applications
Řihák, Marek ; Sovová, Šárka (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis focuses on a preparation of hydrogel systems based on hyaluronan and Septonex and on a design and optimalization of quantitative analysis of hyaluronan and Septonex in a supernatant after gelation. This work compares hydrogels formed from hyaluronan of two different molecular weights. The calibration curves of hyaluronan and Septonex were used to evaluate the experimental data. The thermogravimetric analysis and Fourier-transform infrared spectroscopy were used for the characterization of properties of the samples. The utilisation of the mentioned techniques to study molecular water subpopulations was discussed according to the obtained results.
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Diffusion of dyes in biopolymeric hydrogels
Vyroubal, David ; Mravec, Filip (referee) ; Klučáková, Martina (advisor)
This thesis is focused on diffusion of dyes in biopolymer-based hydrogels. These hydrogels are based on interaction between biopolymer-like electrolytes with oppositely charged surfactants. When polyelectrolytes interact with oppositely charged surfactants, micelle-like nano-containers can be formed. These nano-containers are able of binding hydrophobic compounds. In this study, combination of modified dextran (diethylaminoethyl dextran) with positive charge and oppositely charged sodium dodecylsulphate as surfactant was used for preparation of hydrogels. Next type of hydrogel was based on hyaluronan and positive charged surfactant Septonex (carbethoxypendecinium bromide). As a diffusion probes in hydrogels dyes Nile red and ATTO 488 were used. The diffusion of these dyes from aqeous solutions of NaCl or surfactants into hydrogels was monitored in time. Transport of dyes into structure of hydrogels was characterized by diffusion coefficients and structural parameters of hydrogels.
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Advanced Fluorescence Techniques in Research on Micellar Systems and Their Interactions with Biopolymers
Holínková, Petra ; Burgert, Ladislav (referee) ; Táborský, Petr (referee) ; Pekař, Miloslav (advisor)
The dissertation thesis deals with study of advanced steady-state and time-resolved fluorescence techniques, which can be used for study of micellar systems properties. Selected fluorescence techniques were used for characterization of Septonex and CTAB cationic micellar systems and theirs interactions with hyaluronan. Fluorescent probe pyrene was used for determination of critical micelle concentration (CMC) and micellar aggregation number of these surfactants. The changes of fluorescence behaviour of fluorescein and prodan were studied in wide concentration range of Septonex. Next chapter of thesis deals with study of Förster resonance energy transfer between perylene and fluorescein in Septonex and CTAB micellar solutions and the effect of hyaluronan addition to these systems. Also steady-state and time-resolved fluorescence anisotropy studies were used for research of the effect of hyaluronan addition to micellar solutions. The last chapter of this thesis is focused on photophysical behaviour of Prodan in different solutions (water, Septonex solutions below CMC, hyaluronan solution, Septonex micellar solution and Septonex micellar solution with hyaluronan), which was discussed on the basis of time-resolved emission spectra.
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Hydrogels hyaluronan-surfactant: phase diagram
Gruberová, Eliška ; Hurčíková, Andrea (referee) ; Pekař, Miloslav (advisor)
This bachelor’s thesis deals with phase separation of the hyaluronan-cationic surfactant system in a model physiological solution of 0,15 M NaCl resulting in gel formation. The most widely used concentrations of hyaluronan and a wide range of surfactant concentrations was used to form the gel. We have investigated under which conditions the greatest amount of compacted gel was produced. It has been found that phase separation occurs over the entire concentration range. The largest amount of gel was formed at the highest concentration of both hyaluronan and surfactant. The results were plotted in well-arranged graphs. A hydrophobic colorant was used to indicate the presence of micellar formations and the results were depicted in a schematic phase diagram.
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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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