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Adhesion of the Hydrogels based on Poly(vinylalcohol)
Přibyl, Jiří ; Trudičová, Monika (referee) ; Kalina, Michal (advisor)
This bachelor thesis was focused on the study of adhesion properties of hydrogels based on polyvinyl alcohol using a rheometer. The used hydrogels were divided into three groups, physical, chemical, and modified with starch, PEG or gelatin. Subsequently, the adhesion properties of the hydrogels were determined using a pull off test measured on a rheometer. From the experimental results, the dependences of the adhesion properties on various parameters such as concentration, molecular weight, freezing / thawing process, amount of glutaraldehyde addition and on the type and ratio of added additive were determined. From the following results, it was found that starch is suitable as an additive for increasing the adhesion properties, and on the other side, PEG can be used to reduce the adhesion properties.
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Complex structural characterization of hydrogels based on semi interpenetrating biopolymer networks.
Trudičová, Monika ; Krzyžánek, Vladislav (referee) ; Sedláček, Petr (advisor)
The content of this diploma thesis was testing the applicability of available structural analysis techniques on a appropriate model hydrogel system. The main aim was to evaluate the advantages and disadvantages of selected structural analysis techniques and the influence of the composition change of the hydrogel system on its internal structure. Semi-interpenetrated hydrogels based on agarose of different concentration were chosen as model system, this type of material was chosen for simple and repeatable preparation and also for its application potential. Electron microscopy (SEM, cryoSEM), mercury porosimetry and turbidimetry were chosen as structural analysis techniques. Experimental results could be used to improve knowledge about the influence of hydrogel composition on its structure and the comparison of chosen techniques will be used for the choice of appropriate structural analysis in the future, which will be applicable to other hydrogel systems as well.
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Structural characterization of hydrogels at macroscopic and microscopic level
Kropáčková, Šárka ; Trudičová, Monika (referee) ; Sedláček, Petr (advisor)
This Bachelor´s thesis deals with study of use several methods for structural analysis of hydrogels. The aim was testing selected method to study structure of these gels. Agarose hydrogels were selected as model systems for their easy preparation and wide use. In this work the oscillatory rheology method was used to study the structure. Strain-sweep and time-sweep tests were performed. These tests were performed in a linear viscoelastic region, in the cross-over area and beyond the cross-over area. It was found that in linear viscoelastic region, the deformation causes the non-covalent bonds and the structure of the gel to break through. Consequently there is relaxation of the polymeric site and increase in elasticity. In cross-over area and beyond cross-over gels does not relax. The gels behave like a fluid.
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Elastin hydrogels
Burianová, Veronika ; Trudičová, Monika (referee) ; Jugl, Adam (advisor)
This bachelor thesis is focused on elastin hydrogels for medical application. The aim of the experimental part was using elastin as an additional substance in polysaccharide gel matrices. The most available elastin material was elastin from bovine neck ligament. Because of the insolubility of elastin, it needed to be hydrolysed. Elastin was hydrolysed using potassium hydroxide. The hydrolysis product was soluble and thermal stable elastin peptides, called elastin. Prepared -elastin was incorporated in agarose gel matrices to produce semi-IPN hydrogels based on elastin and agarose. These hydrogels were characterized by rheologicalamplitude and frequency sweeps. The results of measuring clearly proved that -elastin addition caused increased hydrogel stiffness, but other changes were not observed.
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Transport Properties of PVA Hydrogels
Nádvorník, Filip ; Trudičová, Monika (referee) ; Kalina, Michal (advisor)
This bachelor thesis focuses on the study of transport properties of PVA hydrogels. The preparation of PVA hydrogels was optimized using rheological tests and visual observation. The freeze – thawing method was used for the PVA gelation process. Probes carrying a charge on functional groups in aqueous media, namely methylene blue, eosin and riboflavin, were incorporated into PVA hydrogels during the preparation. The mechanical properties of these hydrogels were compared with those of pure PVA hydrogels. Diffusion tests were then carried out where the given dye was monitored from the hydrogel into the surrounding environment using UV-VIS spectroscopy. The obtained results showed that the hydrogel containing the probe with a positive partial charge (methylene blue) showed the greatest willingness to release the dye, while the hydrogel containing the probe without the charge (riboflavin) was released into the environment minimally.
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Adhesion of the Hydrogels based on Poly(vinylalcohol)
Přibyl, Jiří ; Trudičová, Monika (referee) ; Kalina, Michal (advisor)
This bachelor thesis was focused on the study of adhesion properties of hydrogels based on polyvinyl alcohol using a rheometer. The used hydrogels were divided into three groups, physical, chemical, and modified with starch, PEG or gelatin. Subsequently, the adhesion properties of the hydrogels were determined using a pull off test measured on a rheometer. From the experimental results, the dependences of the adhesion properties on various parameters such as concentration, molecular weight, freezing / thawing process, amount of glutaraldehyde addition and on the type and ratio of added additive were determined. From the following results, it was found that starch is suitable as an additive for increasing the adhesion properties, and on the other side, PEG can be used to reduce the adhesion properties.
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An appropriate method for assessing hydrogel pore sizes by cryo-sem
Adámková, Kateřina ; Trudicová, M. ; Hrubanová, Kamila ; Sedláček, P. ; Krzyžánek, Vladislav
The aim of our work was to examine and describe ultrastructure of the agarose hydrogel and any possible structural concentration dependencies, and to assess the distribution and size of pores of agarose hydrogel in dependence on its concentration. Four concentrations were prepared (0.5 %, 1.0 %, 2.0 % and 4.0 % of dry weight content) and cryo-SEM and turbidimetry methods were executed on wet (original) samples in order to image the ultrastructure and measure the pore sizes within. \nReasonable results were obtained for the wet samples as they were closer to their native state they are usually used for applications in. Cryo-SEM and turbidimetry provided comparable results of pore diameters and allowed to compare pore diameters dependant on the concentrations, moreover, it showed more detailed and realistic structure.
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Structural characterization of hydrogels at macroscopic and microscopic level
Kropáčková, Šárka ; Trudičová, Monika (referee) ; Sedláček, Petr (advisor)
This Bachelor´s thesis deals with study of use several methods for structural analysis of hydrogels. The aim was testing selected method to study structure of these gels. Agarose hydrogels were selected as model systems for their easy preparation and wide use. In this work the oscillatory rheology method was used to study the structure. Strain-sweep and time-sweep tests were performed. These tests were performed in a linear viscoelastic region, in the cross-over area and beyond the cross-over area. It was found that in linear viscoelastic region, the deformation causes the non-covalent bonds and the structure of the gel to break through. Consequently there is relaxation of the polymeric site and increase in elasticity. In cross-over area and beyond cross-over gels does not relax. The gels behave like a fluid.
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Structure investigation of hydrogels using a cryo-SEM
Adámková, Kateřina ; Hrubanová, Kamila ; Samek, Ota ; Trudičová, M. ; Sedláček, P. ; Krzyžánek, Vladislav
Hydrogels can be characterized as elastic hydrophilic polymer chains connected in network\nwhich are able to swell notably when exposed to aqueous media by absorbing considerable\namounts of water. Besides being a constituent of living organisms, nowadays, there are\nvarious fields hydrated polymers (e.g. polyvinyl alcohol, collagen, and starch) can be utilized\n– in both biological and non-biological form. Classic examples of such applications are\nhuman health and cosmetics (contact lenses, wound healing dressings and artificial\nreplacement tissues – skin, arterial grafts, cornea and spinal disc replacement), pharmacy\n(drug delivery systems), bioengineering, food industry, agriculture etc. Also, hydrogels\ncan reversibly change their shape when being exposed to a temperature change.
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Complex structural characterization of hydrogels based on semi interpenetrating biopolymer networks.
Trudičová, Monika ; Krzyžánek, Vladislav (referee) ; Sedláček, Petr (advisor)
The content of this diploma thesis was testing the applicability of available structural analysis techniques on a appropriate model hydrogel system. The main aim was to evaluate the advantages and disadvantages of selected structural analysis techniques and the influence of the composition change of the hydrogel system on its internal structure. Semi-interpenetrated hydrogels based on agarose of different concentration were chosen as model system, this type of material was chosen for simple and repeatable preparation and also for its application potential. Electron microscopy (SEM, cryoSEM), mercury porosimetry and turbidimetry were chosen as structural analysis techniques. Experimental results could be used to improve knowledge about the influence of hydrogel composition on its structure and the comparison of chosen techniques will be used for the choice of appropriate structural analysis in the future, which will be applicable to other hydrogel systems as well.
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