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Utilization of thermal and structural analyses in study on the formation of polyelectrolyte complexes
Řiháčková, Barbora ; Sedláček, Petr (referee) ; Krouská, Jitka (advisor)
This bachelor thesis deals with a study of the polyelectrolyte complexes made by chitosan and humic acids. The work was motivated by the research in the field of new materials which can be potentially useful for agricultural and medical applications. A degree and a character of the interactions were studied by isothermal titration calorimetry and dynamic light scattering method. The calorimetric experiments proved that decreasing concentration of samples causes decreasing of reaction enthalpy. Moreover, the temperature changes during the titration are not influenced by water molecules as environment but mostly by the interactions between the functional groups of chitosan and humic acids. The formation of polyelectrolyte complexes was proved also by measurements of intensity of scattered light and Z-average of particle size.
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Use of microcalorimetry in the study of hydration of biopolymers
Bola, Tomáš ; Smilek, Jiří (referee) ; Krouská, Jitka (advisor)
This master thesis deals with the using of microcalorimetry in the study of hydration of biopolymers. Lactose has been selected together with the other biopolymers although it is not among biopolymers but disaccharides. Selected biopolymers are alginate, dextrane, chitosan and hyaluronan of two molecular weights. Lactose has been selected for these purposes mainly because it is a model example to determine whether or not the reaction to moisture between the other samples and the saturated salt solution occurs. The biopolymer hydration study, as opposed to the commonly used perfusion calorimetry method using the possibility of measuring with adjustable moisture has been used an isothermal microcalorimetry method where at two constant temperatures the reaction of the sample to the different moisture released by the saturated salt solution was monitored.
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Preparation and characterization of chitosan-based materials
Puchírová, Simona ; Kalina, Michal (referee) ; Kovalčík, Adriána (advisor)
The presented diploma thesis focuses on the characterization of the rheological properties of hydrogels based on agarose, alginate, polyvinyl alcohol and the study of the antimicrobial effect of chitosan added to selected hydrogels. The theoretical part is focused on the creating a literature research dealing with the description of the basic characteristics of hydrogels in general, describes the nature, properties, structure and possibilities of its use. In the experimental part, hydrogels without added active substance and hydrogels modified with chitosan were prepared. Based on rheological measurements, suitable combinations of hydrogels with chitosan were selected. A part of the hydrogel was taken from the samples and monitored in a drying and re-swelling process in distilled water. The hydrogels were tested by Ftir analysis, which verified the presence of chitosan in the samples. Monitoring of the antimicrobial effect of chitosan was performed by the hole diffusion method. Efficacy was tested on bacterial strains of Escherichia coli, Candida glabrata, Micrococcus luteus, Serratia marcescens. Most excised hydrogel disks have formed zones of inhibition of various sizes. Inhibition zones were also formed around hydrogels without chitosan, where the sensitivity of individual microbial cultures to acetic acid is assumed. The antibacterial active of chitosan was verified by studying the separate sensitivity of chitosan solutions and acetic acid.
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Novel Antibacterial Collagen Scaffolds for Regenerative Medicine
Dorazilová, Jana ; Brtníková, Jana (referee) ; Vojtová, Lucy (advisor)
Tato diplomová práce se zabývá charakterizací 3D porézních kolagenových pěn obsahující vybraná antibakteriální činidla. V literární části jsou shrnuty dosavadní poznatky o biomateriálech a biopolymerech se zaměřením na kolagen a chitosan. Dále jsou v ní popsány antibakteriálních vlastnosti nanočástic v kontextu s využitím selenových nanočástic jako antibakteriální činidla. Pro potřeby této práce byla vybrána antibakteriální aditiva dvojího typu – biopolymerní chitosan a selenové nanočástice. 3D porézní struktury bylo dosaženo metodou lyofilizace. Mechanické vlastnosti biopolymerní matrice byly podpořeny síťováním v prostředí chemického síťovadla na bázi karbodiimidu. K charakterizaci připravených kolagenových pěn byly použity především fyzikálně chemické metody. Na analýzu mikrostruktury a velikosti pórů, vizualizaci nanočástic a jejich distribuci v testovaných materiálech byla využita rastrovací elektronová mikroskopie (SEM) spolu s energiově disperzní analýzou (EDX). Parametry jako je porozita, botnací poměr, úbytek hmotnosti při degradaci ve vodném prostředí a v prostředí enzymů byly zjištěny vhodnými gravimetrickými metodami. Ovlivnění chemické struktury kolagenové matrice před a po přidání antibakteriálních aditiv bylo sledováno za pomocí metody zeslabeného úplného odrazu infračervené spektroskopie s Fourierovou transformací (ATR FTIR). Procentuální uvolnění nanočástic z testovaných vzorků bylo sledováno pomocí optické emisní spektroskopie s indukčně vázanou plazmou (ICP OES). K zhodnocení antibakteriálních vlastností testovaných materiálů byly použity především difúzní agarová disková metoda a makrodiluční bujónová metoda. Provedeným výzkumem jsme zjistili vliv přídavku antibakteriálních činidel na strukturu a některé vlastnosti 3D kolagenových matric. Výsledky antibakteriálních testů ukázaly pozitivní vliv chitosanu i selenových nanočástic na inhibici růstu bakterií v závislosti na koncentraci přidaných aditiv. Navržené materiály mohou být využity pro biomedicínské aplikace především v oblastech zabývající se regenerací měkkých tkání.
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Utilization of biosurfactants for incorporation of hydrophobic domains into modern controlled-release systems
Nešpor, Tomáš ; Pekař, Miloslav (referee) ; Sedláček, Petr (advisor)
This work deals with the current topic of carrier systems. Since the biggest problem is the passage of hydrophobic drugs through the bloodstream, or through universal body barriers (eg blood-brain), it is necessary to chemically modify these carriers in order to be able to administer hydrophobic substances effectively. Based on a literature search, several systems are designed and subsequently studied, in which there is a presumption of possible use for carrier systems and at the same time they have biosurfactants incorporated in them due to their ability to solubilize hydrophobic molecules. The theoretical part of this work will describe the individual biosurfactants, the process of their production, their physicochemical properties, and the possibility of their use in carrier systems. At the same time, the individual carrier systems, the procedure of their preparation, the possibilities of their use are described, and their advantages and disadvantages are also compared. In the practical part, the screening of both individual substances and their mutual interactions, as well as methods used to study the emerging structures is then performed. The study of molecular interactions is primarily performed using the technique of dynamic light scattering. The next part describes the optimization of hydrogel formation with incorporated biosurfactants in their structure and then the formed gels are subjected to rheological and solubilization tests. The study of the internal structure of these gels is performed using a scanning electron microscope.
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Preparation and characterization of novel materials based on combination of humic acids and chitosan
Kozelková, Aneta ; Pekař, Miloslav (referee) ; Sedláček, Petr (advisor)
This bachelor thesis deals with an application potential of newly developed forms of mixed composites of humic acids, chitosan and commercial granulated inorganic fertilizer.. The main aim was to test some preparation methods selected on the basis of literature search. The experimental part focused on characterization of prepared composite materials, the main attention was paid to the sorption of water, release of humic acid and mineral nutrients into solution, and last but not least, on the mechanical properties of resulting materials. The motivation of this work comes from the potential of agricultural and environmental applications of such composites resulting in a renewal of previously exhausted organic content of soils and consequent interruption of substantial soil degradation.
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The use of alternative coagulants in water treatment
Hofmanová, Lucie ; Zelený, Zdeněk (referee) ; Kučera, Tomáš (advisor)
This bachelor's thesis deals with the use of alternative coagulants in water treatment. The first theoretical part mentions types of water treatment for the individual categories of raw water, related laws and ordinances. After that thesis describes the principle, mechanisms of coagulation and factors influencing the process. It analyses the jar test procedure performed within the experimental part of the bachelor's thesis. One chapter deals with polymers and metal coagulants based on aluminium and iron commonly used in water treatment. The chapter includes more detailed description of natural polymers moringa oleifera and chitosan. These two coagulating agents and aluminium sulfate were used in the second experimental part of the bachelor's thesis. Several sets of the jar test were performed in order to investigate the efficiency of chosen coagulants on the removal of turbidity from water. The thesis concludes with a comparison and evaluation of the results. Photos taken during the jar test can also be found at the end of the bachelor's thesis.
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Preparation of edible antimicrobial packaging
Kozubová, Petra ; Dzurická, Lucia (referee) ; Skoumalová, Petra (advisor)
This bachelor’s thesis is focused on preparation and characterization of eatable packaging. Eatable packaging consists of two components, antimicrobial component and base of packaging. The task of eatable packaging is to protect product against antimicrobial attack and to extend durability of the product. As antimicrobial components were used water and oil extracts of several herbs (mint, nettle, lavender, cinnamon, cloves, vanilla, ginger and rhinoceros). Oil extracts were also encapsulated into liposomes for better application. Firstly, concentrations of polyphenoles and antioxidants of extracts were determined. Oil extract of clove contained the highest concentration of both determined substances. Encapsulation efficiency, stability and size of liposomes were tested too. All prepared liposomes were stable and relatively of the same size. Also high encapsulation efficiency was observed. Next, antimicrobial activity of prepared extracts and liposome particles against yeast Candida glabrata and two bacteria strains Escherichia coli and Staphycococcus epidermidis was tested and the high antimicrobial activity reported mainly all tested liposomes. Then alginate, chitosan and carboxymethylcellulose and their combinations respectively were used as bases of packaging. Created film had to meet several parameters, especially suitable sensory properties such as pleasant taste and smell, as well as invisibility, gloss, affordability and suitable manipulability. Combination of 2% carboxymethylcellulose and 1% alginate in a ration of 2:1 with liposomes of mint as antimicrobial component achieved the best results.
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Study on Reactivity of Cationic Biopolymer by Simple Diffusion Techniques
Tesařová, Barbora ; Kalina, Michal (referee) ; Smilek, Jiří (advisor)
This bachelor thesis is focused on study of chitosan reactivity by simple diffusion processes realized in hydrogel media based on agarose. Mechanical properties studied by oscilatory measurements and the pore size were determined at agarose gels with the addition of chitosan as the main parameters influenced the transport properties. The main goal of this work is the investigation the reactivity of chitosan. Agarose is used only as a supporting matrix for the formation of a hydrogel. The state of the art is aimed primarily on the study of chitosan reactivity based on already published scientific papers.
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Preparation and characterization of enzyme-containing wound dressings
Jurová, Bronislava ; Szotkowski, Martin (referee) ; Skoumalová, Petra (advisor)
This diploma thesis is focused on the study and characterization of nanofiber wound dressings from natural biopolymers. Proteolytic enzymes, specifically collagenase and bromelain, were incorporated into these nanofiber covers. The theoretical part deals with a brief description of skin wounds, their healing and skin covers. There are also methods for preparing these covers and the methods used to characterize them. The practical part deals with the optimization of the preparation of nanofiber coatings based on polyhydroxybutyrate, gelatin, alginate and chitosan. These nanofibers were then enriched with active substances and their gradual release into the model environment was monitored. Finally, their proteolytic activity was determined for these substances.
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