|
|
Characterization catanionic vesicular system by HRUS
Kopřivová, Hana ; Sovová, Šárka (referee) ; Hurčíková, Andrea (advisor)
This bachelor thesis is about catanionic vesicular systems, which could serve as carriers of drugs or genes in the future. These systems are prepared from the cationic surfactants CTAB and DDAC, the anionic surfactant SDS and cholesterol, which serves as a stabilizer. In the experimental part, these vesicles were characterized by high-resolution ultrasonic spectroscopy. The behavior of systems with different percentages of cholesterol was monitored. As next, the temperature properties of the vesicles were studied using temperature scans between 10 °C and 65 °C. The density of the samples was examined by densitometry at temperatures of 25 °C and at a human body temperature of 37 °C.
|
|
|
The characterisation of surfactant CAE
Obršlíková, Monika ; Pekař, Miloslav (referee) ; Hurčíková, Andrea (advisor)
CAE is a cationic surfactant derived from DL-Pyrrolidone Carboxylate, L-Arginine and a fatty acid. This surfactant is mainly used in the cosmetic industry. The exact value of critical micellar concentration of CAE is not known yet. In this research there were examined ultrasonic velocity, density, surface tension and scattered light intensity of CAE solutions in ultra-pure deionized water, in 10mM NaCl, 100mM NaCl and 150mM NaCl.
|
|
|
Temperature dependence of carrageenan and hyaluronan solutions
Poledňáková, Halina ; Smilek, Jiří (referee) ; Hurčíková, Andrea (advisor)
This diploma thesis focuses on the study of temperature dependence of -carrageen, hyaluronan of low molecular weight (250–450 kDa) and hyaluronan of high molecular weight (1 500–1 750 kDa) in aqueous solutions. The description of temperature depending changes in properties of these substance is based on rheological method. This work concentrates on the characterization of viscoelasticity through measurement of the storage (elastic) and loss (viscous) modulus using -carrageen and hyaluronan solutions of different molecular weights and different concentrations depending on temperature (20–50 °C, alternatively, in carrageen, 20–80 °C). The temperature dependence was further measured using an uncommon technique called high resolution ultrasonic spectroscopy (HR-US) which measured relative velocity of selected concentrations of -carrageen and hyaluronan of high molecular weight depending on the temperature of heating and cooling (20–80 °C). The measurements of temperature dependence were carried out for varied oscillation frequencies of rheometer sensor/frequency of ultrasonic waves. Knowledge of temperature dependence of the investigated substances may be applied in drug chemistry, primarily with respect to degradation due to high temperatures. The measured data gives information about sol-gel temperature and gel-sol temperature of carrageen.
|
|
|
Characterization of medical biopolymers by ultrasound spectroscopy
Jugl, Adam ; Krouská, Jitka (referee) ; Hurčíková, Andrea (advisor)
Using high resolution ultrasonic spectroscopy has been investigated hyaluron solutions of various molecules weights depending on their concentration and solution temperature. Furhermore, the influence of ionic strenght on the properties of solutions by dissolving hyaluronan in 0.15 M aqueous solution of sodium chloride. For comparison the properties of the hyaluronan solutions were compared with aqueous solutions of carrageenan. It was found that hyaluronan in solution behaves the same, regardless of the weight, temperature and concentration.
|
|
|
Study of interactions of hyaluronan-amino acids
Jugl, Adam ; Smilek, Jiří (referee) ; Hurčíková, Andrea (advisor)
The master´s thesis deals with the study of the interaction between the polysaccharide hyaluronan of diffrerent molecular weights with the amino acids arginine, lysine, arginine hydrochloride and 6-aminocaproic acid. They are expected interaction between carboxyl groups of hyaluronan and amino groups of amino acids. These interactions were investigated by using ultrasonic spectroscopy, DLS, measuring pH and conductivity. Obtained results were compared with sodium polystyrene sulfonate. With ultrasonic spectroscopy was observed a change of concentration inkrement for titration of amino acid to water or polymers solutions especially for high molecular weight hyaluronan and for NaPSS in combination with 6AKK in concentration range of added amino acid 0–30 mM. The size of this change could mean a degree of interaction between polymers and amino acids. This theory has not been confirmed by other methods. By pH and conductivity measurements interations between arginine and low molecular weight hyaluronan and NaPSS were only confirmed. There was no possibility to make unequivocal conclusions from determination of particle size and zeta potential by DLS. Overall, the issue of the interaction of amino acids with polyanions was proved above expectations complex and will be appropriate to further expand the observations made in this thesis.
|
|
|
Characterization of pectin by ultrasonic spectroscopy
Trtek, Jan ; Kalina, Michal (referee) ; Hurčíková, Andrea (advisor)
Pectin solutions of various concentration in water has been investigated using high resolution ultrasonic spectroscopy. Furhermore, the influence of solvent on the properties of solutions by dissolving pectin in 0.15 M aqueous solution of sodium chloride and buffer PBS at pH 7.4. For comparison the properties of the pectin solutions were compared with solutions of pectate. It was found that pectine changes characteristics in differenet solutions. These changes have been observed due to changes in the parameters of ultrasonic waves.
|
|
|
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.
|
|
|
Ultrasound phantoms in medical diagnostics
Koňaříková, Anna ; Pekař, Miloslav (referee) ; Hurčíková, Andrea (advisor)
This bachelor’s thesis studied the relative ultrasonic velocity of gel matrices made of gelatine, agar or agarose depending on concentration and time. These properties have been studied both in the air and water environments, using high resolution ultrasonic spectroscopy. In additon, the basic properties of gel matrices, such as desiccation or moulding, were observed. Relative ultrasonic speed has been found to grow linearly with sample concentration and its changes over time are minimal. Basic gel matrices without added preservatives are able to withstand the usable state only for a week.
|
|
|
Ultrasonic and Densitometric Characterization of Hyaluronan and its Interaction with Surfactant
Hurčíková, Andrea ; Hrdina, Radim (referee) ; Mráček,, Aleš (referee) ; Pekař, Miloslav (advisor)
This disertation thesis is focused on the study of physico-chemical interactions of hyaluronan (with molecular weights from 10 to 1750 kDa) with cationic surfactants measured using uncommon technique named high resolution ultrasonic spectroscopy. Densitometer was also used for the study of these interactions, in measuring of density and ultrasonic velocity of hyaluronan with different molecular weight in dependence on elevated temperature (25 50 °C). The aim is the determination of critical micelle concentration (CMC) and critical aggregation concentration (CAC) of the suractants in the absence and in the presence of hyaluronan with various molecular weights. Interactions in this system are important for the design of the systems for the targeted delivery, especially for the drugs. The experiments were made in water and sodium chloride solution. The significant breakpoint in the ultrasonic velocity showed changes in the system hyaluronan-surfactant.
|
|
|
Hydrogel fantoms in sono diagnostic
Koňaříková, Anna ; Jugl, Adam (referee) ; Hurčíková, Andrea (advisor)
As part of the practical part of this diploma thesis, an internship took place in the Danish company Dansk Phantom Service, which is engaged in the production of ultrasound phantoms. The purpose was to better understand the ultrasound devices used to characterize these phantoms. Part of the phantom material was provided for measurements on ultrasound devices occuring at the faculty of chemistry of BUT to compare results provided by these devices. The follow-up task was to put into operation a digital oscilloscope, which is used to characterize phantoms, and to create a standart operating procedure. Furthermore, the material of the american company Humimic Medical was characterized and the possibilities of its use for the requirements of the Phillips company were assessed, with the subsequent addition of carbon fibers to the material for the modification of phantom properties. The possibility of preparing a viscous phantom from a mixture of agar, glycerol and water with subsequent charakterization of experimental samples was also investigated. It was found that the values from different ultrasound devices are comparable, differing only in small deviations. Humimic’s Medical material has potencial for specific applications, as does carbon fiber for property modification. A basic mixture of viscous phantom was created that would potentially meet the requirements. However, this basic mixture need to be further modified.
|
guest ::
