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Characterization of liposomes as precursors for the preparation of models of cellular membrane using scattering techniques
Gjevik, Alžběta ; Kalina, Michal (referee) ; Mravec, Filip (advisor)
The bachelor thesis presents a cellular membrane design based on lecithin, cholesterol and POPG basis. It summarizes formation mechanisms, optimization techniques and characterization methods of model cellular membranes. It focuses on preparation of liposomes with various lipid compositions as precursors for model membranes preparation and characterization. Small unilamellar liposomes were formed by thin layer evaporation, thin layer rehydration in phosphate buffer and sonication. Size and stability (-potential) of formed liposomes were measured using dynamic light scattering. Successful supported lipid bilayer formation on glass surface by vesicular fusion was tested using the most stable lipid composition. SLB was characterized by Z-scan fluorescence correlation spectroscopy.
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|Preparation and characterization of micro- and nanoparticles with selected drugs
Sosková, Simona ; Bokrová, Jitka (referee) ; Márová, Ivana (advisor)
The presented bachelor thesis is focused on the way to prepare combined micro- and nanoparticles containing some natural extracts with antioxidant effects, ibuprofen as the anti-inflammatory and analgetic agent and clotrimazole as the agent with an antifungal effect. The theoretical part contains an introduction of the methods of liposome preparation and a review of encapsulation techniques, methods of particles characterization, and analysis of active substances content. Furthermore, the yeasts of the genus Candida and the methods of the antimicrobial activity determination are described. The mentioned components were encapsulated into liposomes, alginate and chitosan particles. The antioxidant activity of the extracts was determined spectrophotometrically. The encapsulation effectivity of active substances into particles and the long-term stability of encapsulated components were determined and compared too. The HPLC method was used for measuring of the concentration of drugs and spectrophotometric method was used to quantify the content of polyphenols. Prepared particles were characterized with DLS method (size) and zeta- potential (stability). Finally, antibacterial properties of prepared particles and extracts using the test system Candida glabrata were studied. The antimycotic effect of particles, disturbed liposomes and extracts was compared. Finally, potential utilization of prepared liposomes in a cosmetic or pharmaceutical product is proposed.
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Application of nanoparticles and nanofibers with active compound in cosmetics
Pavelková, Renata ; Obruča, Stanislav (referee) ; Márová, Ivana (advisor)
Presented bachelor thesis is focused on application of nanoparticles and nanofibers with active compound in cosmetics. The theoretical part is aimed at effect of UV radiation on the skin and compounds that are used in photo protection of the skin. The materials and methods used in nanoparticle and nanofiber preparing were characterized. The experimental part deals with preparing of liposomes and marinosomes with active compound. Particles size, stability measured using zeta potential and stability in model environment were observed. Finally, pilot experiments of optimization of nanofibers preparation using electrospinning were carried out.
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Preparation and use of selected nanoparticles in cosmetics
Hoová, Julie ; Němcová, Andrea (referee) ; Márová, Ivana (advisor)
The Bachelor thesis is focused on preparation and use of selected nanoparticles in cosmetics. The theoretical part deals with general characterization and use of caffeine, phenolics and vitamin C in cosmetics. Further, characterization of liposomes and possibilities of encapsulation of active substances gained from natural sources were introduced. In experimental part liposomes with encapsulated active substances were prepared by three different techniques. Encapsulation efficiency was determined by HPLC/PDA, phenolics spectrophotometrically and vitamin C by titration. Prepared particles were monitored for size and stability by dynamic light scattering. Furthermore, long-term stability of liposomes in model conditions was evaluated as the amount of the active substances released during incubation. In this work was found out that from all tested samples co-encapsulated liposomes are probably the best application form which can be used in face lotion or gel. Co-encapsulated liposomes exhibited relatively high encapsulation efficiency, good stability and thanks to quality of active substances they meet customer’s requirements of cosmetic industry.
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Antimicrobial peptides and their application into foods
Janhuba, Filip ; Petrik, Siniša (referee) ; Márová, Ivana (advisor)
The presented thesis is focused on a study of antimicrobial peptides and their potential applications into foods. Two types of antimicrobial peptides were studied in detail - bacteriocin nisin and antimicrobial enzyme lysozyme. In theoretical part an overview of antimicrobial peptides used in food industry was introduced. The experimental part of this work was focused on optimization of methods for the determination of antimicrobial peptides concentration. Commonly used spectrophotometric methods for quantitative analysis of total proteins as well as high performance liquid chromatography were tested. To determine the molecular weight and purity a modified SDS-PAGE with the addition of urea and tricine buffer was performed. Further, encapsulation of nisin into liposome was tested. Encapsulated particles were prepared by three different procedures: by ultrasonication, ethanol injection and TLE. Particles stability, distribution and size were studied by dynamic light scattering. Stability of encapsulated peptides in model conditions and model foods was studied too. Finally, antibacterial properties of the selected peptides using test system Bacillus subtilis were studied. Nisin already showed antimicrobial effect at low concentrations - about 1 µg/ml. The inhibitory effect of nisin was more evident in liquid cultures.
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Encapsulation of caffeine
Patočková, Klára ; Pekař, Miloslav (referee) ; Márová, Ivana (advisor)
This bachelor thesis is focused on possibilities of encapsulation caffeine in micro- and nanoparticles. In the theoretical part was devoted to information about caffeine, liposomes and polysaccharides and also on the techniques of encapsulation. In the experimental part 5 different methods were used for preparation of micro- and nanoparticles with encapsulated caffeine. Caffeine was packaged into liposomes and polysaccharide particles (chitosan/alginate). Encapsulation’s effectiveness was determined by HPLC/UV-VIS. Prepared particles were monitored for size and stability by dynamic light scattering. The particles were exposed to the arteficial stomach and intestinal juices and bile acids. Particle stability and amount of released caffeine was monitored. Analytical centrifugation was used to measurement of sedimentation velocity and stability of the prepared particles. Caffeine containing particles were added in several soft drinks to determine particles amount when turbidity occurred.
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Characterization and stabilization of pancreatin
Wurstová, Agáta ; Němcová, Andrea (referee) ; Obruča, Stanislav (advisor)
This work focuses on a study of enzyme mixture pancreatin, its characterization and subsequent encapsulation into liposomes. As a reference proteins bovine serum albumin and trypsin were used. Characterization of pancreatin consisted of two parts. The first part focuses on optimization of methods for the concentration determination by absorption spectrophotometry using basic methods for identifying proteins (Biuret method, Hartree-Lowry method and Bradford method). Moreover, UV spectrums of the protein were measured. As a method for identification of protein´s molecular weight, SDS-PAGE was used. To identify components of pancreatin, LPLC was employed in two modifications, ion-exchange chromatography and size exclusion chromatography. The second part is dedicated to the characterization of pancreatin as enzyme in terms of pH and temperature optimum for the enzyme activities of protease (pH 9, 8 and 50 °C), amylase (pH 7 and 40 °C) and lipase (pH 7 and 50 °C). The last part of this work aimed at an encapsulation of pancreatin into liposomes and DLS analysis of distribution of particles and their zeta potential. Liposomes did not spontaneously release encapsulated enzyme. To confirm that proteins were successfully entrapped into liposomes, their structure was disrupted by application of phospholipase D. In conclusion, liposomes can be utilized as delivery systems for native enzymes.
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Transport systems used in cosmetics
Škopová, Jitka ; Kramářová,, Daniela (referee) ; Zemanová, Jana (advisor)
Between transport systems in cosmetics belong liposomes, liquid crystals and also chosen substances, which speed under given conditions a transport of active compounds, so-called accelerators of trans-dermal penetration. Liposomes are used topically (i.e. directly onto the place of their action in surface structures of organism) in dermatological and cosmetic preparations, they facilitate the penetration of active substances into the deeper layers of the skin and make possible their more expressive treatment. Some properties of liquid crystals are similar to the properties of live organisms. Analogous to the vital cells are they sensitive to light, sound, warm, mechanical straining and chemical changes. And by contraries, some scientists mark vital cells as liquid crystals. Thanks to this similarity are liquid crystals characterized by their excellent ability to penetrate by the skin, which is probably comparable only with liposomes. Accelerators of trans-dermal penetration otherwise accelerators of penetration by the skin are substances, which change structure of the skin or derma to be more permeable for other compounds. The trans-dermal penetration of active substances is an important part of medical researches. Those results are however applied also in other branches as for example is cosmetic industry. From the point of view of the chemical texture of these materials form they a very heterogeneous group and an elucidating of mechanisms of their incidence is so far rather in beginnings.
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Characterization of Liposomes Used as Model System of Biological Membranes by Glassy Carbon Electrode
Parisová, Martina ; Navrátil, Tomáš ; Šestáková, Ivana ; Barek, J.
This contribution deals with study and characterization of liposomes. These vesicles may serve as model membranes used for study of transporting processes of heavy metal ions across the real phospholipid membranes (PLMs). 1,2-dioleoyl-sn-glycero-3-phosphocholine was used for the formation of large unilamellar vesicles (LUV). These vesicles were prepared by hydration method. Interactions of cadmium ions with LUV in solution have been characterized using voltammetry, where glassy carbon electrode was used as the working electrode. Size and presence of liposomes in sample was proved by dynamic light scattering and free cadmium ions in samples were determined by differential pulse voltammetry.
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