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Passive microrheology of colloidal systems based on biopolymers.
Bjalončíková, Petra ; Burgert, Ladislav (referee) ; Mravec, Filip (advisor)
Diploma thesis was aimed to deal with evaluation of microrheology method in the research of biopolymer-protein. Used biopolymer was sodium hyaluronate and proteins were trypsin and chymotrypsin. For measuring of microrheology were used particles with different radius (0,5 m and 1 m). It was found, that both substances have viscous charakter. Passive microrheology is suitable for measuring the viscoelastic properties of biopolymers.
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Interaction between surfactants and hyaluronan with different molecular weight.
Vašíčková, Kamila ; Lehocký,, Marián (referee) ; Pekař, Miloslav (advisor)
The behavior of the system consisted by mixture of two different molecular weight hyaluronates and surfactant was investigated. Mixtures were 17 kDa hyaluronate with 1,46 MDa, 73 kDa with 1,46 MDa, 300 kDa with 1,46 MDa, 806 kDa with 1,46 MDa and 1800 kDa with 1,46 MDa. These compounds were always mixed in the weight ratios 70:30, 50:50 and 30:70. As the surfactant cetrimonium bromide and TWEEN 20 were used. Interactions were studied in aqueous solution with different ionic strength. Sudan red was used as hydrophobic dye. In all experimental series with cetrimonium bromide was observed phenomenon of discontinuous separated phases, described as pearls. Samples containing pearls were tested on stability, were dried and rehydrated back, as were also heated in solution. Subsequently, the particle size was measured in the remaining sample after pearls were filtrated. Mixtures of hyaluronate were characterized by measuring the viscosity using rheology microrheology. It was found that these compounds are heterogeneous and each sample point is not the same viscosity.
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Microrheology in study of biopolmer colloids.
Hnyluchová, Zuzana ; Sedláček, Petr (referee) ; Mravec, Filip (advisor)
A new method for determining the viscoelastic properties of materials was introduced and investigated. Results of three groups of samples obtained using one particle microrheology method, DLS microrheology method and classical rheology method were compared to be sure of correctness of measurements. As a model system were chosen mixtures of glycerol of different viscosities. In case of samples containing glycerol, results were also compared with tabulated values. Hyaluronan of various molecular weights was used as a biopolymer and polystyrene particles were used for microrheology. It was confirmed, that viscosity values of biopolymer samples obtaining by each method are comparable.
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Microrheological study hyaluronan solutions after exposure to low temperatures
Habánková, Eva ; Sedláček, Petr (referee) ; Mravec, Filip (advisor)
The aim of this bachelor thesis is to study the influence of a repeated freezing and thawing process to hyaluronan solutions. The thesis is meant to determine if repeatedly exposing hyaluronan solutions to low temperatures may change the arrangement of the polymer chains and develop weak interactions between these chains. In the thesis the applicability of the two microrheological methods was verified and these were single particle microrheology and dynamic light scattering. For microrheological measurements we used polystyrene particles with a diameter of 0,5 m. There was an effort to determine changes in the structure of hyaluronan solutions by changing the dependence of mean square displacement of particles on time and by changing viscosity of the hyaluronan solutions. Infrared spectroscopy was used as the accompanying method but it proved to be unsuitable for this purpose.
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Microrheology with Fluorescence Correlation Spectroscopy
Kábrtová, Petra ; Sedláček, Petr (referee) ; Mondek, Jakub (advisor)
A comparison of three passive microrheological techniques was made with the emphasis on FCS. Fluorescently labelled and unlabelled polystyrene particles were used to probe a microrheological response of glycerol solutions, Mili-Q water and sodium hyaluronate solutions. In addition, for FCS technique an approximated equation for calculation of MSD values was derived and verified. It was found that FCS outmatches current microrheological techniques of DLS and video-based particle tracking by its ability to gain a broader data range including the area in which, until now, it was impossible to describe a microrheological behaviour of samples reliably.
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Microrheology in systems of polymeric colloids
Bjalončíková, Petra ; Sedláček, Petr (referee) ; Venerová, Tereza (advisor)
My bachelor’s thesis was aimed to deal with evaluation of microrheology method in the research of polymer colloids. Used polymers were poly(sodium 4-styrenesulfonate) and sodium carboxymethyl celullose. For measuring of microrheology were used particles with different radius (1 m and 4 m). The results obtained with passive microrheology were compared with results obtained with clasical rheology. It was found, that both substances have viscous charakter. The values of polymer viscosity were similar for dilute solutions in both methods, but for concentrated solutions deviations were found. The reason are polymer nets, which do not allow sufficient movement of particles in concentrated solutions.
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