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Hyaluronan micro- and nanoparticles
Mourycová, Jana ; Marián, Lehocký (referee) ; Pekař, Miloslav (advisor)
The aim of this thesis was to prepare hyaluronic acid micro- and nanoparticles based on electrostatic interactions with oppositely charged molecules. Following parameters were monitored: correlation function behavior, the particle size and zeta potential value. At the beginning, it was necessary to study the behavior of hyaluronan in solution by dynamic light scattering measurement. Micro- and nanoparticles were prepared by mixing different volume ratios of negatively charged hyaluronan and positively charged polyarginine or cetyltrimethylammonium bromide. Micro- and nanoparticles were prepared in aqueous solution as well as in 0,15 M sodium chloride solution (physiological solution). In the case of the hyaluronan solution a polydisperse character of hyaluronan was detected. It was found that the dissolution of hyaluronan in the physiological solution gives us the smaller particle size in opposite to particle size obtained from the same concentrations of hyaluronan dissolved in water. Furthermore, it was found that systems composed of hyaluronan and polyarginine create particle size of about 100 nm. Whereas systems consisting of cetyltrimethylaminoum bromide and hyaluronan form larger particles, in units of hundreds of nanometers, the particle size in physiological solution were smaller than the same systems dissolved in aqueous solution.
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Kinetic study of excited state proton transfer in polymer-surfactant system
Bačová, Jana ; Vala, Martin (referee) ; Mravec, Filip (advisor)
In this bachelor thesis were studied interactions between hyaluronic acid and cationic septonex by steady-state and time-resolved fluorescence with fluorescence probes pyrene and 1-naphthol. At first was determined critical micelle concentration of septonex. In the case of both fluorescence probes was studied area below and above critical micelle concentration. It was found, that 1-naphthol undergo very fast deprotonation in aqueous solution, while in the present of micelles the rate of deprotonation is c significantly retarded. In the system of hyaluronic acid – septonex it was observed, that formation of aggregates occurs at lower concentrations than in the system without hyaluronic acid. Molecules of probe are probably distributed between hyaluronic acid – septonex aggregates and free micelles above critical micelle concentration.
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An investigation of lubrication of knee joint replacement
Sýkora, Tomáš ; Horák, Zdeněk (referee) ; Nečas, David (advisor)
This diploma thesis deals with an experimental analysis of knee joint replacement lubrication. The experiments were realized at a knee joint simulator which can apply conditions according to certain standard and survey the phenomena by using fluorescence microscopy. The aim of thesis is to clarify the influence of particular components of synovial fluid on the lubrication process. The intensity of fluorescence expresses dimensionless parameter of a lubrication film thickness. There was a fundamental study with mineral oils before the experiments with the synovial fluid. The study allows to have a look at contact transformation during walk. Results are shown in graphs as dependency of intensity on time, including pictures showing phenomena in the contact zone. Experiment results show that protein -globulin creates a layer on the surface. There is albumin on the layer and it makes the lubricating film thicker. The protein interaction is supported by hyaluronic acid and fosfolipids which stabilizes the created structure. According to lubrication is behaviour of film related to a complex structure of synovial fluid. Thesis gives more information about behaviour of synovial fluid and can be used for future development of knee replacements.
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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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Preparation of nanoparticles and their use as contrast agents for in vivo imaging.
Odehnalová, Nikola ; Kratochvílová, Irena (referee) ; Turánek,, Jaroslav (advisor)
This diploma thesis deals with the optimalization of synthesis of gold nanoparticles and their surface modification allowing their use as contrast agents for in vivo imaging by CT. Gold nanoparticles were prepared by the Turkevich method and characterized by TEM, DLS, MADLS and UV -Vis. Their surface was functionalized with polyethylene glycol containing a thiol group forming a bond with the Au atoms in the surface of gold nanoparticles. The terminal end of the polymer was methylated or containing an aminooxy group forming an orthogonal bond with hyaluronic acid using click-chemistry. The eligibility for in vivo application of the prepared nanoparticles was verified with stability and cytotoxicity tests. The nanoparticles modified by methylated polyethyleneglycol were injected intravenously into a mouse and their application potential as contrast agents were verified by CT.
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Influence of polysaccharides on caffein absorption from beverages
Osecká, Karolína ; Márová, Ivana (referee) ; Pekař, Miloslav (advisor)
This bachelor thesis was focused on investigation of the interaction between the polysaccharide sodium hyaluronan (HA) and the alkaloid caffeine (CAF). The reason why this thesis was focused on study of aqueous solutions of hyaluronan with caffeine is that presence of polysaccharide can slow down the realising from hyalurona-caffeine complex. At first, it was determined whether the photophysical properties of caffeine reacts in different polarity solvents. Based on these results was studied the interaction of caffeine and hyaluronan using the fluorescence. Emission and excitation spectra of caffeine were observed. The HA of molecular weight of 1.7 MDa were chosen for the study of the interactions with the caffeine of concentration the caffeine contained in coffee. The results of interaction that would result to influence the emission properties of CAF, not show. In acidic solutions leading to the formation of various shapes of HA and by centrifugation it was determined whether HA in this form interacts with CAF, which was shown to decrease the absorbance of the supernatant in the CAF. The solution and the mixtures were measured in four types of environment in hydrochloric acid solutions at different pH. The influence of constant addition of caffeine and the HA of molecular weights of 1.7 MDa with different concentrations in different acidic solutions. As a part of the work was to determine how hyaluronan behaves in strongly acidic solution. And then determine the pH in model gastric juices after intake of Coca Cola and Kofola. The obtained results can be used as for description of the behavior of caffeine in the presence of selected polysaccharide.
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Fluorescence correlation spectroscopy in colloid systems
Janíček, Tomáš ; Smilek, Jiří (referee) ; Mravec, Filip (advisor)
This work is focused on studying of stability and interaction in colloidal systems created by micelles of surfactant CTAB in solution of hyaluronic acid and water. As method chose for this work was selected fluorescence correlation spectroscopy. As dye was used Nile red. Measurements were divided firstly by size of polymeric chain and secondly by concentration of hyaluronic acid. Purpose of this work was to find out how will CTAB particles react with different sizes and concentration of hyaluronic acid. For comparison to hyaluronic acid was used Poly(sodium-4-styrenesulfonate).
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Preparation of model membranes to study their interactions with biopolymers using fluorescence correlation spectroscopy
Adamcová, Zuzana ; Márová, Ivana (referee) ; Mravec, Filip (advisor)
This diploma thesis is focused on preparation and characterization of supported lipid bilayers as simplified models of cell membranes. The bilayers were prepared from source system of lecithin liposomes in phosphate buffer using the vesicle fusion method on a cover glass sufrace hydrophilized by plasma. Three fluorescent probes – Nile red, Oregon Green DHPE and DiO – were utilized to characterize diffusion within the bilayer using fluorescence correlation spectroscopy. For this purpose Z-scan FCS, which is a method developed specially for planar samples, was used. After the process of preparation and characterization of supported lipid bilayer was optimalized, interaction between this artificial membrane and solution of hyaluronic acid in phosphate buffer was studied. It was found out, that addition of this biopolymer causes slowing the diffusion of the fluorescent probe within the bilayer.
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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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Modification of hyaluronan by cholic acid and the using of these derivatives for carrier applications
Kvaková, Klaudia ; Márová, Ivana (referee) ; Velebný, Vladimír (advisor)
Amphiphilic biopolymers were synthesised using esterification of hyaluronic acid (HA) and cholic acid as hydrophobic segment. First, step of synthesis involves the activation of cholic acid carboxylic moiety by reaction with benzoylchloride and triethylamine (TEA) using as solvent tetrahydrofuran (THF). The formed mixed aliphatic/aromatic anhydride (intermediate) reacted at room temperature with hyaluronic acid catalysed by 4-(dimethylamino)pyridine (DMAP) and triethylamine and using as solvent water/THF. Hydrophobized product was identified as sodium cholyl hyaluronate (HA-CA) was obtained as product of the reaction. Structure of derivative was characterised by Nuclear magnetic resonance (NMR) and Fourier Transform - Infrared Spectroscopy (FT-IR). Size exclusion chromatography (SEC-MALLS) was used to determine molecular weight of derivative to evaluate any possible degradation of hyaluronan during modification. Rheological properties of these substances were also examined and confirmed non-degradation. The hydrophobized hyaluronic acid properties were evaluated for application as drug delivery system. Therefore, two non-polar compounds were encapsulated (coenzyme Q10 and curcumin). The size of formed polymeric micelles was characterised by dynamic light scattering (DLS).
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