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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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Interactions and aggregation in hyaluronan-aminoacid-surfactant systems
Venerová, Tereza ; Velebný, Vladimír (referee) ; Pekař, Miloslav (advisor)
The effect of native hyaluronan addition on CMC of excluded surfactants (Tween 20, BETADET THC 2, SDS, CTAT a CTAB) in physiological solution (0,15 M NaCl) has been investigated by fluoresence spectroscopy with Pyrene and Nile red as probes. The greatest influence on CMC has been observed in systems with cationic surfactant. System of cetyltrimethylamonnium bromid has been closely studied. Solubilization experiments with a hydrophobic dye Sudan red has been realized and aggregation number of this system has been determinated via fluorescence quenching with cetylpyridinium chloride as quencher and Pyrene as fluorescence probe. Addition of hyaluronan (native or hydrophobicaly modified) reduces aggregation number of system.
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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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Studying the quality of hydrophobic domains in the phase separated hydrogels
Burešová, Natálie ; Pekař, Miloslav (referee) ; Mravec, Filip (advisor)
The thesis deals with the study of hydrophobic domains in phase separated hydrogels. Two types of polyelectrolytes (hyaluronan, dextran) and oppositely charged surfactants (carbethopendecinium bromide, sodium dodecylsulphate ) are used. Phase separated hydrogels are formed by electrostatic interactions. The target of the thesis is to study the polarity of environment in phase separated hydrogeles by fluorescence spectroscopy. Fluorescence measurements is performed by using pyrene, Nile red and laurdane as fluorescence probes. All probes are sensitive to the polarity of the environment. The results showed that probes can be expected in the polar environment of hydrogels.
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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 microscopy in the research of colloidal systems
Valovič, Stela ; Venerová, Tereza (referee) ; Mravec, Filip (advisor)
This bachelor thesis is focused on dual-colour fluorescence cross-correlation spectroscopy. As a suitable combinations of fluorescenct dyes were designated this combinations: perylene + nile red, perylene + DiD and DiO + DiD. The funtionality of this method was veried by tetraspeck. The experiment of FCCS was performed on micellar surfactants solitions which proved to be unsuitable for this method. Consequently, liposomes with DiD and DiO incorporated in phospholipid bilayer were measured. The cross-correlation in liposomes was succesfuly measured.
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Using diffusion techniques in the study of hydrogels
Holubová, Anna ; Žitňan, Michal (referee) ; Mravec, Filip (advisor)
Properties of colloidal systems, especially hydrogels, were studied using the method of fluorescence correlation spectroscopy (FCS). Hydrogels were prepared based on hyaluronan and cationic surfactant CTAB interactions. The proposed hydrophilic fluorescent probe, suitable for the study of phase-separated hydrogels in polymer-surfactant systems, was chosen ATTO 488 due to the suppression of triplet state. As a hydrophobic probe was chosen Nile Red. Individually were examined micellar systems of 10 mM CTAB and 0,5% sodium hyaluronate in water and 0,15 M NaCl in different concentrations of selected fluorescent probes. Subsequently the hydrogel systems were studied. The results showed that the measurement of hydrogels by this method is realizable. Short lifetimes were created by a complex probe and CTAB causing quenching and low levels of diffusion coefficients characterize the viscous environment of study system.
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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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Influence of the preparing of a biopolymer-surfactant system on its aggregation behavior.
Pilgrová, Tereza ; Sedláček, Petr (referee) ; Pekař, Miloslav (advisor)
To study the effect of the method of preparation of biopolymer-surfactant on the aggregation properties several experiments were designed. Closer investigation was made on native hyaluronan-cetyltrimethylammonium bromide (CTAB) system. The system has been studied in the phosphate buffer in aqueous and saline solutions. The effect of the order of substances addition in the samples, the influence of different methods of preparation of certain concentrations of the solutions or the effect of dissolving powdered biopolymer and surfactant on the contrary, the resulting system were investigated. Fluorescence intensity was measured for all prepared samples and its changes were investigated. Pyrene and Nile red were used as fluorescent probes. Some samples were also measured by tensiometer. Measurement of surface tension was based on the method of divorcing the ring from the surface. It was found that the order of the mixing of solutions has a significant effect on the aggregation properties of the system and its appearance. Further effects were detected on the prepared samples by dissolving powdered biopolymer surfactants and vice versa, and environmental influences of the polarity of the system. It was found that sodium chloride abolished the effects of interactions in the system. Effect of method of preparation of certain concentration of CTAB in phosphate buffer is reflected only slightly.
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Transport properties of hyaluronan-based hydrogel systems
Káčeríková, Martina ; Smilek, Jiří (referee) ; Klučáková, Martina (advisor)
This bachelor thesis deals with the study of trasport properties of hydrogels, that were prepared by interaction of hyaluronan with karbethopendecinium bromide (Septonex), as a surfactant. Nile red is a fluorescent probe to determine the ability of the system to absorb or to release the substance. All the hydrogels were prepared by the „wet“ way, where the solutions of hyaluronan and surfactant were prepared first. Nile red was prepared in the solution of tenzide, which after the mixing with hyaluronan produced colorful gels. By the spectrophotometric measurement, the absorbance of supernatants were observed. The absorbance was measured in original but also in changed supernatatns after 24, 72 and 168 hours.
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