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Hybrid gellan hydrogels
Borovský, Martin ; Přibyl, Jiří (referee) ; Krouská, Jitka (advisor)
The subject of this bachelor thesis was the preparation of hybrid gellan hydrogels based on the combination of physical crosslinking and ionic interaction of the functional groups of gellan with multivalent ions of selected metals. These materials were subsequently characterized by analysis on their mechanical properties, ability to swell in aquatic environment, and by studying of their rate of drying using drying scales. The results of the study indicate that hybrid crosslinked hydrogel networks provide better mechanical properties, thus these hydrogels have high application potential. From the obtained data it was found that hydrogels with the addition of multivalent ions exhibit a higher degree of crosslinking of their hydrogel network, which positively affects the resulting properties of the hydrogels. By using different types of ions at variable concentrations, the hydrogels with a wide range of properties can be prepared. In conclusion, the experimental findings are summarized and an overview of the influence of multivalent ions on the mechanical properties of hydrogels is provided.
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Rheological characterization of polysaccharide gels with incorporated vesicles
Kalendová, Lucie ; Smilek, Jiří (referee) ; Venerová, Tereza (advisor)
This diploma thesis deals with the rheological characterization of polysaccharide gels with incorporated vesicular systems. Positively charged Ion Pair Amphiphile vesicles (IPA) consisting of cetrimethylammonium bromide, sodium dodecyl sulfate, dioctadecyldimethylammonium chloride and cholesterol were chosen for the incorporation. Other vesicles used for incorporation were oppositely charged liposomes made of phosphatidylcholine (DPPC), phosphatidic acid (PA) and cholesterol. The thesis is divided into two sections. The first one deals with preparation, characterization and stability control (temperature and time stability) of both vesicular systems by using dynamic light scattering (DLS). In this part, the vesicles’ stability was confirmed which made them perfect candidates for the following incorporation. The second part of the thesis describes the preparation and rheological characterization of selected gels. Three types of gels were prepared in total, specifically 1% and 2% gellan gum gels and 4% hyaluronic gel. All of them were studied in water, as well as in solutions of IPA vesicles or DPPC liposomes, both of same concentration (1 mmoll-). The subsequent rheological characterization including amplitude, frequency, and stress relaxation sweeps demonstrates there is no significant difference between reference gels and those containing vesicles. This indicates that vesicles used in this thesis were only freely stored in the gel networks, meaning the structure of the gels didn’t affect their transport properties. This is a significant information for using these systems in drug delivery.
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Transport and mechanical properties of hybrid hydrogel networks based on gellan
Sokolínský, Jan ; Pekař, Miloslav (referee) ; Kalina, Michal (advisor)
This diploma thesis deals with the characterization of the mechanical and transport properties of gellan based hybrid hydrogels. As part of this work, the process of optimizing the preparation of gellan-poly(vinylalcohol) IPN hydrogel was first studied with an emphasis on the repeatability of the preparation due to the preservation of mechanical properties of the hydrogel. Then, both on the gellan hydrogels themselves and on selected IPN compositions, the effect of various additives was studied (specifically, the effect of the addition of a plasticizer and the effect of cross-linking by polyvalent ions). Based on these tests, a set of samples was selected, on which dynamic mechanical analysis, swelling and drying experiments were additionally measured. At the end of this diploma thesis, the transport properties of selected hydrogel compositions were also studied. The tests conducted in this thesis revealed that both the formation of a dual network and the addition of the mentioned additives allow us to influence the studied properties.
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Hydrogels with incorporated proteins
Uhrínová, Alžbeta ; Mravec, Filip (referee) ; Venerová, Tereza (advisor)
This work deals with associative peptides. The aim was to characterize a given associative protein and perform experiments leading to the creation of a hydrogel system containing the selected protein. Casein solutions were initially prepared to determine micellar concentration (CMC) using a pyrene fluorescence probe. Subsequently, the micelles were characterized by dynamic light scattering (DLS) and their size, zeta potential and also the effect of temperature on these properties were determined. Based on the characterization of the particles at temperature, suitable gels were selected into which the protein particles were subsequently incorporated.
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Transport Properties of Gellan Hydrogels
Sokolínský, Jan ; Sedláček, Petr (referee) ; Kalina, Michal (advisor)
This bachelor thesis deals with the characterization of mechanical and transport properties of gellan based hydrogel systems. As gellan gum is a biopolymer, hydrogels based on this biopolymer are suitable candidates for use in the pharmaceutical industry and medical applications. The characterization of mechanical properties was realized by rheological analysis and by drying scales, transport properties were characterized by diffusion experiments in combination with the detection using UV-VIS spectrometry. The result of this work is a comparation and commentary of the measured data, in order to provide an overview of the properties of physical gellan gum hydrogels. It was found out that by changing the concentration of the biopolymer and by a suitable selection of the dispersion medium, transport, and mechanical properties of the physical gellan gum hydrogels can be modified.
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Mechanical and Transport Properties of Hybrid Hydrogel Systems
Klímová, Eliška ; Sedláček, Petr (referee) ; Kalina, Michal (advisor)
This master´s thesis deals with the study on mechanical and transport properties of hybrid hydrogel systems. Considering applications of hydrogels, especially in chemical industry, pharmacy, or eventually medical applications, for the study gellan and alginate-based hydrogels were selected. In order to compare individual characteristics physical and hybrid hydrogels were prepared. Gellan hydrogels were prepared in deionization aqua solution, calcium chloride dihydrate and tween 80 solution. Alginate hydrogels were prepared in calcium chloride dihydrate solution as well, and polyacrylamide with N,N´–methylenbisacrylamide. For the study of mechanical properties moisture analyser and rheology measurements were selected. Transport properties were studied using the diffusion experiments combined with UV-VIS spectroscopic detection. Concluding of this thesis is summarization of measured values, which provides comprehensive review of the problematics. It was discovered that the conveniently selected concentrations of structural components of hydrogel matrix and the additives can influence both the mechanical as well as the transport properties of studied hydrogels.
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Composite hydrogels
Blechová, Dominika ; Smilek, Jiří (referee) ; Venerová, Tereza (advisor)
The content of this bachelor's thesis is research on the topic of composite hydrogels and subsequent research on the rheological properties of prepared hydrogels from the polysaccharide – Gellan, as well as the determination of the properties of hydrogels with the addition of two types of particles – IPA vesicles and a mixture of hydroxyapatite and calcium sulfate particles obtained by the breakdown of PerOssal pellets (PO particles). Hydrogels are prepared with three different concentrations of Gellan – 1%, 1.5% and 2%. The properties of hydrogels prepared in this way were determined using frequency and mainly amplitude tests. Furthermore, two different methods of applying the sample to the measuring plate of the rheometer were compared. The commonly used method of slicing the sample has been replaced by injection application. The injected samples were measured, the results evaluated and compared with the results of the gels applied by slicing.
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Hydrogels with incorporated proteins
Uhrínová, Alžbeta ; Mravec, Filip (referee) ; Venerová, Tereza (advisor)
This work deals with associative peptides. The aim was to characterize a given associative protein and perform experiments leading to the creation of a hydrogel system containing the selected protein. Casein solutions were initially prepared to determine micellar concentration (CMC) using a pyrene fluorescence probe. Subsequently, the micelles were characterized by dynamic light scattering (DLS) and their size, zeta potential and also the effect of temperature on these properties were determined. Based on the characterization of the particles at temperature, suitable gels were selected into which the protein particles were subsequently incorporated.
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Transport Properties of Gellan Hydrogels
Sokolínský, Jan ; Sedláček, Petr (referee) ; Kalina, Michal (advisor)
This bachelor thesis deals with the characterization of mechanical and transport properties of gellan based hydrogel systems. As gellan gum is a biopolymer, hydrogels based on this biopolymer are suitable candidates for use in the pharmaceutical industry and medical applications. The characterization of mechanical properties was realized by rheological analysis and by drying scales, transport properties were characterized by diffusion experiments in combination with the detection using UV-VIS spectrometry. The result of this work is a comparation and commentary of the measured data, in order to provide an overview of the properties of physical gellan gum hydrogels. It was found out that by changing the concentration of the biopolymer and by a suitable selection of the dispersion medium, transport, and mechanical properties of the physical gellan gum hydrogels can be modified.
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Mechanical and Transport Properties of Hybrid Hydrogel Systems
Klímová, Eliška ; Sedláček, Petr (referee) ; Kalina, Michal (advisor)
This master´s thesis deals with the study on mechanical and transport properties of hybrid hydrogel systems. Considering applications of hydrogels, especially in chemical industry, pharmacy, or eventually medical applications, for the study gellan and alginate-based hydrogels were selected. In order to compare individual characteristics physical and hybrid hydrogels were prepared. Gellan hydrogels were prepared in deionization aqua solution, calcium chloride dihydrate and tween 80 solution. Alginate hydrogels were prepared in calcium chloride dihydrate solution as well, and polyacrylamide with N,N´–methylenbisacrylamide. For the study of mechanical properties moisture analyser and rheology measurements were selected. Transport properties were studied using the diffusion experiments combined with UV-VIS spectroscopic detection. Concluding of this thesis is summarization of measured values, which provides comprehensive review of the problematics. It was discovered that the conveniently selected concentrations of structural components of hydrogel matrix and the additives can influence both the mechanical as well as the transport properties of studied hydrogels.
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