| Recent research topics |
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| Molecularly ordered nanolayers of amphiphilic compounds |
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Chemical, structural and adhesional stability of multilayer Langmuir-Blodgett films in vacuum and aqueous environment was investigated by X-ray photoelectron spectroscopy, surface sensitive positron annihilation spectroscopy and atomic force microscopy. A correlation was found between the chemical composition of fatty acid(salt) films and their vacuum stability, layer structure, and the chemical change caused by X-ray exposition. The LB-films proved to be stable in water but a significant dissolution or peeling type degradation was observed in aqueous electrolyte solutions depending on the way of contact. |
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| Surface and interfacial properties of systems with biological relevance |
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| Protein adsorption at fluid interfaces |
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The interfacial adsorption of proteins was investigated in two-liquid systems with low interfacial tension related to a separation process (three-phase partitioning, TPP). Model experiments with various proteins allowed us to conclude that the protein-collecting third phase is an emulsion gel obtained by sequential processes of interfacial adsorption of proteins, emulsification, aggregation and gelation. The amount of the protein separated was found to be correlated to the interfacial activity of the protein and its interfacial rheological behaviour as well. The interfacial activity and dilatational behaviour of the protein film are also used to characterize protein fractions with biological activity obtained from food sources. |
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| Surface modification of polymeric biomaterials |
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Various methods such as wet chemical processes, plasma treatment, application of polymer blends, or copolymer adsorption were developed for surface modification of biodegradable polymers with the aim to improve their biocompatibility. The chemical composition of the surface layer determined by XPS and its wettability properties showed a considerable surface immobilization or accumulation of the modifying poly(ethylene oxide)-compound increasing the hydrophilic character of the polymers. Molecular interaction of the polylactid or polylactid/glycolid copolymers and the modifying additive was studied using the Langmuir balance technique. Stability of the composite layer was found to be dependent on the molecular weight and structure of the PEO-containing surface active block copolymers. |
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| Membrane affinity |
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Interfacial properties of biorelated systems are studied to estimate membrane affinity of drug candidates and antibacterial agents. Various model systems are used as Langmuir lipid monolayers, supported lipid bilayers and liposomes. Molecular interactions between bioactive compound and membrane components are characterised quantitaively determining degree of penetration applying Langmuir-balance and Langmuir-Blodgett technique. The structural details of the interaction are visulaised by Atomic Force Microscopy. This approach provides a high through put method in selection of promissing drug molecules from numerous candidates and contributes to the reveal the mechanism of transport through the cell membrane. |
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