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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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Preparation and Characterization of Mechanical Properties of Artificial Synovial Liquids
Hrochová, Eliška ; Sedláček, Petr (referee) ; Kalina, Michal (advisor)
This bachelor thesis deals with the optimization of preparation of artificial synovial liquids. The main subjects of study are the mechanical properties of real and artificial synovial fluid samples. DLS microrheology, thermogravimetric analysis (TGA) and infrared spectroscopy (FTIR) were used for characterization. The theoretical part of this thesis is represented by a literature research of a methods of preparation of artificial synovia and summary of definitions of rheological terms. The experimental part focuses on the preparation and characterization of the artificial synovial liquids originating from the published patent US 8716204. In the framework of the bachelor thesis, this preparation was optimized in several partial steps (method of dispersion of components, choice of molecular weight of hyaluronic acid, nature and ionic strength of used dispersion medium). The prepared optimized sample of synovial fluid was in following experimental characterization steps compared in terms of material characteristics and mechanical properties with the real horse synovial fluid sample. By modifying the process based on the aforementioned patent, an artificial synovial fluid could be formed. That meets the viscoelastic nature of the real matrix and that is stable over time.
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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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Studium dynamiky živých lidských buněk v odezvě na běžné kontaminanty vod s cílem vývoje citlivého specifického analytického postupu
KOŠEK, Jan
The bachelor thesis is devoted to testing the toxicity of chemical substances. In the current chemical and pharmaceutical industry, thousands of new substances are produced annually, which brings about the need to ensure sufficient consumer safety and environmental protection. In vitro testing is becoming an increasingly important research tool in this issue. This work verifies the theoretical foundations and proposes an algorithm developed by Lonhus et al. from the Laboratory of experimental complex systems in Nové Hrady and its possible future applications in in vitro testing. This new approach uses the principles of microrheology and tracks Speed-Up Robust Features (SURF) in a digital image and converts them into vectors of trajectories of intracellular mass particles. Microrheology is a relatively new field of research in life sciences and deals with the study of flow and deformation of materials at the microscopic level. The algorithm separates two main components of the movements inside the cells: direct movement of organelles as larger particles and random Brownian motion. The advantage of this method is its potential of easy use and sensitivity. The method makes it possible to obtain important primary information about the effect of chemical substances on cell cultures.
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Microrheology modeling with COMSOL Multiphysics package
Koláček, Jakub ; Sedláček, Petr (referee) ; Pekař, Miloslav (advisor)
This bachelor thesis focuses on modeling Brownian motion using the COMSOL Multiphysics package and its Particle Tracing module. The aim of the work is to design and create elementary models that will be able to suitably simulate the movement of microparticles in viscous and viscoelastic environments, which can later be used for modeling passive microrheology. Within this work, Matlab scripts were created for the calculation of MSD from the simulation results, validation of the viscous model was performed on experimental data and elementary models for the simulation of the viscoelastic environment were also designed. Two different approaches were chosen for the design of these models, namely the use of rigid obstacles under the assumption of a discrete environment and a mathematical model assuming continuous environment. Data from the viscous model showed good agreement with the experimental results. The results of viscoelastic simulations are presented, and further possible development of these models is discussed. The continuous mathematical model is considered closest to modeling viscoelastic behavior because of a characteristic curvature that was observed in the evaluation of MSD.
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Derivatization of Sodium Hyaluronate as a Possible Tool for Increasing of the Stability of Model Artificial Synovial Fluid
Hrochová, Eliška ; Mravec, Filip (referee) ; Kalina, Michal (advisor)
This master thesis deals with the optimization of the procedure of modification of hyaluronic acid structure for the use in the artificial synovial liquids. Based on the literature research, the amino acid alanine was used for the modification of carboxylic group in the glucuronic acid. The main subject of study is the improvement of the stability and mechanical properties of synovial liquid. DLS microrheology, macrorheology, thermogravimetric analysis (TGA), multi-angle light scattering with flow-field flow fractionation (AF4-MALS) and infrared spectroscopy (FTIR) were used for characterization. The theoretical part of this theses submits review of the musculoskeletal system, role of hyaluronic acid in metabolism and summary of synovial liquid. The experimental part focuses on the measurement of the stability and mechanical properties of three artificial samples (first with no modification, second with modified hyaluronic acid and third with modified hyaluronic acid and chondroitin sulphate). These samples were compared with real horse synovial fluid and artificial viscosupplement Orthovisc®.
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Preparation and Characterization of Mechanical Properties of Artificial Synovial Liquids
Hrochová, Eliška ; Sedláček, Petr (referee) ; Kalina, Michal (advisor)
This bachelor thesis deals with the optimization of preparation of artificial synovial liquids. The main subjects of study are the mechanical properties of real and artificial synovial fluid samples. DLS microrheology, thermogravimetric analysis (TGA) and infrared spectroscopy (FTIR) were used for characterization. The theoretical part of this thesis is represented by a literature research of a methods of preparation of artificial synovia and summary of definitions of rheological terms. The experimental part focuses on the preparation and characterization of the artificial synovial liquids originating from the published patent US 8716204. In the framework of the bachelor thesis, this preparation was optimized in several partial steps (method of dispersion of components, choice of molecular weight of hyaluronic acid, nature and ionic strength of used dispersion medium). The prepared optimized sample of synovial fluid was in following experimental characterization steps compared in terms of material characteristics and mechanical properties with the real horse synovial fluid sample. By modifying the process based on the aforementioned patent, an artificial synovial fluid could be formed. That meets the viscoelastic nature of the real matrix and that is stable over time.
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Time-Resolved Fluorescence in Research of Hyaluronan-Colloidal Systems Interactions
Mondek, Jakub ; Táborský, Petr (referee) ; Peter, Kapusta (referee) ; Pekař, Miloslav (advisor)
The aim of the doctoral thesis was to study advanced fluorescence techniques and its use in colloids or hyaluronan-surfactant systems and hydrogels based on hyaluronan, respectively. Steady-state and time-resolved fluorescence were used to study excited state proton transfer fluroescen probes in hyaluronan-surfactant systems to asses the influence of hyaluronan hydration to its interactions with oppositely charged surfactants. Firstly, different excited state proton transfer fluorescence probes were discussed to choose the most suitable candidate for next research. The influence of hyaluronan on inner environment of micells was determined based on the sensitivity of excited state proton transfer of chosen fluorescence probe 1-naphtol and, based on above mentioned experiments, the structure of hyaluronan hydration shell was discussed. The next part of doctoral thesis was focused on fluorescence lifetime correlation spectroscopy and on the development of method of nanorheology. Measured correlation functions were transformed to mean square displacement with developed MATLAB script. Firstly, the fluorescence method was compared with well described methods such as videomicrorheology and dynamic light scattering to asses the reliability of fluorescence correlation spectroscopy in microrheology. Secondly, nanorheology method was developed and its use in passive nanorheology of hyaluronan hydrogels was discussed. Based on mentioned experiments, the fluorescence correlation spectroscopy microrheology and nanorheology methods were optimized to use the methods in hydrogel research.
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Advanced microrheological techniques in the research of hydrogels
Kábrtová, Petra ; Smilek, Jiří (referee) ; Mravec, Filip (advisor)
This diploma thesis deals with the use of fluorescence correlation spectroscopy technique for microrheological characterization of hydrogel in a system of hyaluronate-cetyltrimethylammonium bromide. Fluorescently labelled particles were used for microrheological FCS analysis. To optimize the method the most appropriate size of particles was chosen on the basis of Newtonian glycerol solutions analysis. Among other things, the discussion was focused on the influence of refractive index change of analysed solutions on analysis results. After hyaluronate solutions analysis it was possible to assess the biopolymer concentration and molecular weight impact on the FCS microrheology results, which could then be compared with analysis results of model hydrogels of hyaluronate and CTAB. Finally, usability and limitations of FCS microrheology have been discussed.
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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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