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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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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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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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Influence of conditions on hydrogel preparation
Heger, Richard ; Kalina, Michal (referee) ; Mravec, Filip (advisor)
This work is focused on testing the influence of conditions, more precisely pH, during the creation of hydrogels that were prepared through the hydration of powdery mixtures, by another name solid-mixture way. The hydrogel system was made from a polyelectrolyte, more accurately sodium hyaluronate and a cationic surfactant, CTAB. The influence of pH was studied through observation and rheology. For measuring purposes, the hyaluronan with the molecular weight of 600-800 kDa was used. The system was examined via a series of buffers with the pH of 3,5-11. The gels were dyed by Sudan III for better observability and description. It was found that the best way of adding an active substance was by adding a dye directly into a powdery mixture. The observed properties of the gels didn’t change even after the gels were modified to the ionic strength of a physiological saline solution (0,15 M).
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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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Optimizing the determination of distribution of surfactant at phase separation in polymer-surfactant system
Sátorová, Kateřina ; Pekař, Miloslav (referee) ; Mravec, Filip (advisor)
This diploma thesis is focused on the determination of distribution a surfactant at phase separation in polymer-surfactant system. Sodium hyaluronate of three molecular weights was chosen as a polymer, CTAB was used as a surfactant. The experiments were performed in an environment of 0,15 M NaCl. The measurement of the CTAB concentration in samples was based on the formation of coloured complexes of CTAB and picric acid in chloroform. UV-VIS spectroscopy was used for the detection of these complexes. The content of CTAB was determined in four gels of different composition (2% Hya + 200 mM CTAB, 2 % Hya + 50 mM CTAB, 0,5 % Hya + 200 mM CTAB, 0,5 % Hya + 50 mM CTAB). All gels were gradually washed five times with 0,15 M NaCl. The content of CTAB was determined for newly prepared gels and for gels after 2 and 4 months since the preparation. Initial concentrations of CTAB and hyaluronan have greater influence on the distribution of CTAB after phase separation, than the molecular weight of hyaluronan. The content of CTAB in newly prepared gels and after 4 months since preparation is very similar and demonstrates the stability of the system.
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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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Synthesis of colloidal gold nanorods for biomedical applications
Valkovičová, Jiřina ; Bernard, Vladan (referee) ; Drbohlavová, Jana (advisor)
Diplomová práce se zabývá výrobou a využitím zlatých koloidních nanotyčinek v biomedicínských aplikacích. Konkrétně se zaměřuje na tři základní funkce nanočástic v analýze - transportní, separační a především zobrazovací. V části o využití nanočástic pro zobrazování je hlavní zájem věnován zejména povrchové plazmonové rezonanci zlatých nantyčinek. Dále je práce zaměřena na využití nanotyčinek pro termální terapii. Následující část je věnována vhodným modifikacím povrchu, hlavně za účelem zmírnění toxicity částic. Závěrem teoretické části jsou způsoby přípravy zlatých koloidních nanotyčinek a techniky jejich následné analýzy. V navazující experimetální části jsou uvedeny postupy, podmínky a výsledky provedených pokusů.
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Hyaluronan hydrogels for medical applications
Janča, David ; Krouská, Jitka (referee) ; Venerová, Tereza (advisor)
This work studies properties of hydrogels prepared by the interaction of polyelectrolyte hyaluronate with cationic surfactant cetyltrimethylammonium bromide (CTAB) in a model physiological solution of 0,15 M NaCl. Effects of different pH and final pH of different samples of hydrogels were studied. Furthermore, stability of hydrogels was observed by fluorescence spectroscopy, where pyrene was used as a fluorescence probe, and isothermal microcalorimetry. It was found that low temperature disrupts gel integrity and it is not recommended to expose hydrogels to other than a neutral pH.
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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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