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Excited-state proton transfer as a tool for characterization of coloid particles
Richterová, Veronika ; Pilgrová, Tereza (referee) ; Mondek, Jakub (advisor)
This bachelor thesis deals with the study of excited-state proton transfer in micellar systems. At first critical micelle concentration of surfactants CTAB, SDS and Triton X-100 was determined. Further the steady-state and time-resolved fluorescence of probes that undergo excited-state proton transfer with these surfactants was measured. As probes were chosen 1-naphthol, HPTS and 3HNA. Deprotonation rates of 1-napthol and HPTS and average lifetime of 3HNA were calculated from time-resolved measurement. Steady-state fluorescence was used for observation surfactants influence on excited-state proton transfer.
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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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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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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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Anisotropy and time-resolved anisotropy techniques in colloidal systems research
Holínková, Petra ; Táborský,, Petr (referee) ; Mravec, Filip (advisor)
In this diploma thesis were investigated in terms of microviscosity liquid and condensed systems composed of hyaluronan (Hya) and cationic surfactant cetyltrimethylammonium bromide (CTAB). The excitation and emission spectra, lifetime, steady-state fluorescence anisotropy and time-resolved fluorescence anisotropy of the samples were measured. First, was studied the formation of hydrophobic domains in the system Hya-CTAB at concentration of CTAB lower than its critical micelle concentration in an aqueous solution and 0.15M NaCl. It was found that in an aqueous solution small hydrophobic domains linked to chains Hya are formed. Then an increasing concentration of CTAB leads to phase separation and formation of gel. Due to the addition of NaCl then leads to the reorganization of this system and probably the formation of free micelles in the solution. Were also studied condensed phase of system Hya-CTAB-NaCl at high concentrations of surfactant during fourteen days of ageing. It was found that the microviscosity of hydrophobic domains is constant, but the microviscosity of hydrophilic parts gradually decreases.
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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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Transport of Biomedical Active Compounds Through Porous Membranes
Vašíčková, Kateřina ; Smilková, Marcela (referee) ; Smilek, Jiří (advisor)
This bachelor thesis deals with a study of transport of biomedical active compounds through porous membranes. The main goal is to optimize a penetration method of micellar solutions with a solubilized dye and subsequently with solubilized drug. Cetyltrimethylammonium bromide is chosen as a surfactant and a nile red dye is used as a diffusion and fluorescence probe. Selected active compound is a nonsteroidal anti-inflammatory drug ketoprofen with analgesic and antipyretic effects. The diffusion processes are realized using Franz diffusion cells with polycarbonate membrane with a 2 µm size of poruses. The samples are withdrawn in a chosen time intervals and afterwards evaluated by a fluorescence correlation spectroscopy. Using this method, it is possible to screen the diffusion in time even in nanomolar concentrations of a fluorescence probe chosen. This thesis provides an overview of nile red behaviour in the micellar solutions of surfactant during diffusion processes. The experiment can be extended using an active compound, for instance using a ketoprofen as it is mentioned above.
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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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Quality of hydrophobic domains in polyelectrolyte-surfactant system
Holínková, Petra ; Vala, Martin (referee) ; Mravec, Filip (advisor)
In this bachelor thesis were studied the photophysical properties of four fluorescent probes depending on the viscosity of their surroundings by the fluorescence spectroscopy. For probes DPH, DPB a perylene was determinated dependence of fluorescence anisotropy and for P3P dependence of ratio excimer/monomer on the viscosity of the sample. Anisotropy probes DPH and perylene were also used to study interaction between hyaluronan and cationic surfactant CTAB (concentration below CMC) in aqueous solution and 0,15 M NaCl. Information about forming hydrophobic domains were obtained by measurement of fluorescence intensity and anisotropy depending on the concentration of CTAB in the sample. It was found that in an aqueuos solution, after the initial addition of CTAB to hyaluronan formed small hydrophobic domains linked to chain of hyaluronan. Increasing concentration of CTAB leads to the formation of gel and phase separation. After addition of NaCl leads to reorganization of this system and probably the formation of free micelles in the solution with higher concentration of CTAB.
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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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