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Preparation and characterization of nanoparticles with encapsulated antimicrobial component
Dohnalová, Marie ; Strečanská, Paulína (referee) ; Márová, Ivana (advisor)
This bachelor thesis is focused on the preparation and characterization of particles with encapsulated natural substances with antioxidant and antimicrobial properties. Selected antioxidants were anthocyanins, eugenol and vitamin E, as one of the most powerful antioxidants. At the same time, antimicrobial agents were chosen, in this case eugenol. In the theoretical part, individual active substances, materials for the preparation of particles, methods of their preparation were characterized and the principle of determining the safety of used materials. In the experimental part, selected active substances were characterized and the preparation of particles was optimized. Two types of liposomes were prepared, for which the encapsulation efficiency, size and stability were determined. Also prepared aqueous extracts of blueberries and blackberries were prepared, for which total anthocyanin content has been determined. The extracted substances from the plant material were encapsulated into alginate particles. Furthermore, the gradual release of active substances from particles into model environments using a spectrophotometer was determined. During the gradual release of active substances from the particles, the antioxidant effect was also monitored, in which it was possible to observe a decrease with the passage of time. The antimicrobial effect of active substances and liposomes against model microorganisms Escherichia coli and Micrococcus luteus was also tested. Cytotoxicity tests on human keratinocytes were performed on selected active substances, extracts and prepared nanoparticles, where it was proven that the selected materials are non-cytotoxic. Finally, a proposal for a possible application form in the form of an alginate hydrogel was created.
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Combined preparatives with encapsulated antimicrobial component
Kneblová, Kateřina ; Bendová, Agáta (referee) ; Márová, Ivana (advisor)
The presented bachelor thesis deals with the preparation and characterization of liposome nanoparticles that have been functionalized by the active substance and subsequently tested for their synergistic effect against microorganisms. In the theoretical part, a research focused on an overview of antimicrobials agents and on encapsulation techniques. In the experimental part, the method of sonification was used to prepare liposomes. Natural and synthetic antimicrobial substances were encapsulated into the particles. The size, stability, encapsulation efficiency, antioxidant and antimicrobial activity were determined for the liposomes that were prepared. Antimicrobial activity was tested on the gram-negative strain Esterichia coli, the gram-positive bacteria Micrococcus luteus, and one fungual strains Candida glabrata. Subsequently, a synergistic effect of the active substances was observed, which was demonstrated both when combining a synthetic active substance with a natural one and when combining two natural active substances. The synergistic effect of the encapsulated substances was observed after a longer period of time than that of the synergy of the pure active substrances. Which could find its application in the pharmaceutical industry, in drug delivery, or in the food industry in preservation processes.
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Study of the release of active substances from PHA-based particles
Čech, Jan ; Mikulíková, Renata (referee) ; Kovalčík, Adriána (advisor)
This bachelor thesis deals with the study of the release kinetics of caffeic acid and acetylsalicylic acid from polylactic acid, poly(3-hydroxybutyrate-co-4-hydroxybutyrate) and poly(3-hydroxybutyrate)-based microparticles. In the theoretical part, the mechanical and thermal properties of polyhydroxyalkanoates, their biological synthesis by microorganisms, their industrial extraction from biomass and applications are described. Furthermore, the properties of PHA microparticles, their use as carriers, the most common microparticle preparations and the release method of the loaded drug are described. In the experimental part, PLA, P(3HB) and P(3HB-co-4HB) based microparticles prepared by the solvent evaporation emulsion method were characterized by dynamic light scattering. Subsequently, caffeic acid or acetylsalicylic acid was incorporated into these microparticles, and the release kinetics of the active ingredient was observed spectrophotometrically for one week. Once measurement of the releasing kinetics ended, microparticles were again measured by DLS and compared with the characterized microparticles before releasing kinetics. Finally, the encapsulation efficiency and microparticle recovery were calculated.
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Optimization of the production of yogurt with increased protein content from wheat bran
Adamczyková, Michaela ; Vítová, Eva (referee) ; Pořízka, Jaromír (advisor)
This thesis deals with the use of wheat bran in the form of protein isolate as an additive in the food industry, optimalization of the formula of fortified yoghurts and the encapsulation of plant proteins, used as a method to mask the negative sensory properties of products with the addition of these proteins. The theoretical part deals with the characterization of fermented milk products, wheat bran as a source of protein and the possibilities of masking the negative sensory properties of protein isolates. The produced yoghurts were sensory evaluated and their nutritional and technological properties were analyzed in the experimental part. By sensory analysis of yoghurts made from different types of milk, full-fat UHT milk was determined to be the best for the production of fortified yoghurts. Yoghurts prepared from this milk were fortified with wheat bran protein isolate. The products thus had an increased nutritional value, but their sensory values deteriorated. The yoghurts had a gritty feel, which was subsequently mitigated by grinding the protein isolate to finer parts. The formula for the production of fortified yoghurts was optimized by the addition of alternative protein, which had a positive effect especially for yoghurts with a 10% protein content. Yoghurts with protein isolate were evaluated with a negative score for the bitter taste parameter. Encapsulation of proteins significantly reduced the intensity of the bitter taste. Synergy of all prepared samples was determined by filtration. Yoghurt from full-fat UHT milk showed a syneresis of 31.76 ml per 100 g of yoghurt. The addition of protein led to a change in the synergy of this yoghurt. From the rheological analysis, it was determined that 10% yoghurt with encapsulated particles had a higher value of dynamic viscosity and yield stress. Sensory analysis data were evaluated using principal component analysis.
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DEVELOPMENT AND TESTING OF NATURAL FOOD COMPOUNDS FOR INFANTS´ NUTRITION
Hoová, Julie ; Kráčmar, Stanislav (referee) ; Vítová, Eva (referee) ; Márová, Ivana (advisor)
The presented doctoral thesis is focused on development and testing of natural compounds for infant’s nutrition. Selected groups of plant-based food were examined from nutritional point of view, as well as regarding the content of biologically active compounds, especially compounds with antioxidant and antibacterial activity. As basic nutrients were measured following groups of compounds: total saccharides, reducing sugars, insoluble fiber, total nitrogen, and fatty acid profile. Moreover, content of specific vitamins and provitamins, total phenolic compounds, flavonoids, antioxidant capacity, natural pigments, fructans, -glucans and organic acids were determined in selected samples. The evaluation of antimicrobial effect was studied via interaction with appropriate types of microbial cells. The safety of tested materials was verified by cytotoxicity tests using human cell lines HaCaT and Caco-2. In next part of present work, encapsulation techniques were applied to enhance stability and consumer acceptance of natural extracts. Materials were encapsulated into nanoparticles, especially into liposomes of different composition. Size distribution, uniformity, zeta potential, encapsulation efficiency and release control were monitored. Sunflower and soya bean lecithin were determined as the most suitable for preparation of stable liposomes. Further part of the study was focused on the role of probiotics in infant´s nutrition. Selected probiotic strains were cultivated and the influence of the encapsulation techniques and presence of plant extracts on probiotic viability were examined in natural form and in model digestion conditions. Cultivation techniques and flow cytometry were performed to evaluate probiotic viability. Based on the results obtained, plant extracts rich in bioactive compounds and having potential effect on human organism and probiotic bacteria were selected. As a most suitable combination, green barley and some probiotics like lactobacilli and bifidobacteria could be recommended. Finally, the specific study focused on the transfer of selenium species from mother to child via colostrum was analyzed. Selenium is a biogenic element acting as a representative of early natural antioxidants in human body. The important role of colostrum in neonatal nutrition was confirmed by the detection of the presence of selenoprotein P in the colostrum. This protein is further taken up by the child immediately after birth and contributes as the earliest antioxidant to infant´s immunity. Overall, it can be concluded that, despite the undeniable fundamental importance of protein in childhood nutrition, further plant-based biologically active compounds and combinations of probiotics and prebiotics, represent a major benefit and contribute positively to the increase of the nutritional value and quality of foods for infant nutrition.
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Theoretical insights into encapsulated noble metals
Hou, Dianwei ; Heard, Christopher James (advisor) ; Logsdail, Andrew (referee) ; Rubeš, Miroslav (referee)
Noble metals are widely used in industry due to their excellent catalytic and optical properties. Because of limited reserves and high prices, it is desired to make effective use of every atom. It has been possible in recent years to produce subnanometer clusters or even isolated atoms, despite their low resistance against sintering. Furthermore, it has been recently established that the encapsulation of single atoms and subnanometer noble metal clusters can be achieved via trapping at metal oxides, ranging from two-dimensional layered materials to the void space within the pores of zeolites. However, neither the atomistic mechanisms of atom/cluster trapping, nor the means by which they may be optimized are known. Furthermore, the relationship between the physical and electronic state of trapped atoms/clusters and their reactive properties in catalysis are currently only weakly understood. In this thesis, we used theoretical methods ranging from global structure optimization to kinetic Monte Carlo to identify the roles of cluster size, charge state, and the present and type of common adsorbents on the stability, catalytic and optical properties of subnanometre-sized noble metal clusters trapped at metal oxides. This thesis takes the form of three sections: (1) Structure, stability, and migration...
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Development of antimicrobial wound healing nanostructure biomaterials
Hanák, Jan ; Wikarská, Monika (referee) ; Márová, Ivana (advisor)
The bachelor thesis is focused on optimizing the production of nanoparticles with a bioactive component - especially on enzymes and antibiotics encapsulated into lipozomes. Nanoparticles with active substances could be used in the field of pharmacy or cosmetology. In the theoretical part the composition of the skin, skin injuries, and wound covers are described. The materials used for the preparation of nanoparticles and nanofibers are characterized as well as processes to produce such nanomaterials. Enzymes, antimicrobial drugs, and methods for determining antimicrobial activity are mentioned in this section, too. The practical part deals with the characterization and optimization of the formation of lipozome particles with encapsulated enzymes. The formed particles were divided into two groups. The first type of particles were pure lipozomes, while the second ones enriched by polyhydroxybutyrate to increase the encapsulation efficiency and improve the stability of the particles. The enzymes bromelain and lysozyme were selected for the highest encapsulation efficiency. The encapsulation of these two enzymes took place in two ways - by thin film hydration and by sonication method. Both methods showed high encapsulation efficiency, but the sonication method proved to be unsuitable due to enzyme denaturation. The proteolytic activity of the released enzymes from the particles was measured. The stability of the particles was monitored in a physiological and aquatic environment by measuring the zeta potential for up to 28 days. Moreover, the enzymes, ampicillin, and particles created by sonication were subsequently subjected to antimicrobial tests by using two test bacterial strains. Finally, alginate particles with encapsulated enzymes were also formed, then the encapsulation efficiency and proteolytic activity of the enzyme were measured. In this study also other methods of encapsulation of active substances are outlined, which could be possibly used to produce nanomaterials suitable for wound healing.
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Encapsulation of vitamins and provitamins into nanoparticles
Martinusíková, Katarína ; Wikarská, Monika (referee) ; Skoumalová, Petra (advisor)
This bachelor thesis is focused on the encapsulation of vitamins in liposomes and the subsequent observation of the properties of this form. The theoretical part is focused on the history of vitamins, their classification into groups, but mainly the general characterization of all vitamins. It describes their function in the human body, the consequences of their deficiencies and also the sources of their income. It also describes the technique of encapsulation in liposomes and their characterization and use in the food industry. The experimental part is focused on the preparation of specific liposomes of vitamins and their mixtures. These prepared liposomes are subsequently characterized by properties such as size, stability and encapsulation efficiency. Long-term stability of prepared liposome particles over 2 and 5 weeks were also investigated. In the conclusion of this thesis are summarized all the results of observations and the subsequent suggestion of the possible use of this technique in food products.
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Design of a fluidizing device for encapsulation
Lizúch, Ján ; Skácel, Josef (referee) ; Otáhal, Alexandr (advisor)
The aim of a bachelor´s thesis is to design and construct a model of fluidized bed for encapsulating a hybrid integrated circuits. A theory about hybrid integrated circuits, their packages, principles of fluidized bed and about organic materials suitable for fluidization is included in a first part of the thesis. Next parts of the thesis discusses a design of a theoretical model and its practical construction part. Thesis also contains a part about fluidization process optimalization for a specific encapsulating material.
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Self-encapsulation of Plant Growth Promoting Rhizobacteria as a way towards new generation of bioinoculants
Gašparová, Dominika ; Obruča, Stanislav (referee) ; Sedláček, Petr (advisor)
This bachelor thesis focuses on Plant Growth-Promoting Rhizobacteria that can be used as a suitable ecological alternative to conventional fertilizers. However, most of today's approaches to incorporating PGPR into the process of soil fertilization are convoluted and costly. Crosslinking of alginate self-produced by PGPR offers a new possibility of plantgrowth- promoting bacteria encapsulation. The aim of this thesis consists of preparing gel matrices with incorporated bacteria, followed by testing the bacteria's viability and quantity. Firstly, experiments were carried out to determine various properties of gels produced by the chosen representative bacteria Azotobacter vinelandii. These properties include the molecular weight of alginate (with the highest molecular weight of strain CCM 289 (329,78± 6,8) kDa), the alginate's amount in the gel, the content of PHB (34%-44% CDW), and the gel's overall rheological properties. The complex modulus (as a representation of rheological properties) of the firmest gel reached the value of 13,34 kPa. The bacteria content was examined by flow cytometry, the CFU method, and spectrophotometry. The viability of bacteria was determined by analyzing the fluorescence intensity via fluorescent dyes (propidium iodide, fluorescein diacetate, rhodamine 123, calcein AM), then by using the CFU method, and also via the plate method. Furthermore, the effects of various factors such as different pH levels (pH 3, 7, and 10) or adding the specific alginatedegrading enzyme alginase were also examined. Releasing of the bacteria was observed over the course of seven days using flow cytometry and the CFU method. The plate method proved the bacteria's survival after gelation and without any source of carbon. The largest disintegration of gels occurred in acidic pH. Moreover, the effect of alginase on crosslinked bacterial gels and synthetic alginate were very similar. The survival of bacterial cultures in gel and their continuous release are significant findings in the development of novel bioinoculants based on this new concept.
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