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Mechanical Properties of Hydrogels - Comparison between DMA and AFM Measurements of Elastic Modulus
Hofrichterová, Tereza ; Valentová, Helena (advisor) ; Shukurov, Andrey (referee)
Polymer hydrogels consist of polymer network that is able to absorb large amount of water. They have plenty of real-life applications - for example in medicine and diagnostics. The aim of this thesis is to study elastic modulus of several hydrogel samples by two different methods - dynamical mechanical analysis (DMA) and atomic force microscopy (AFM). Dynamical mechanical analysis represents a traditional method, which is expected to supply very reliable data. On the other hand - there has not been done much research in the field of studying mechanical properties with atomic force microscopy yet. This thesis should result into comparison of these two methods and describing effects that influence the measurement.
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Bioactive interfaces between synthetic surfaces and biological fluids
de los Santos Pereira, Andrés ; Brynda, Eduard (advisor) ; Shukurov, Andrey (referee) ; Šubr, Vladimír (referee)
Title: Bioactive interfaces between synthetic surfaces and biological fluids Author: Andrés de los Santos Pereira Institute: Institute of Macromolecular Chemistry, Czech Academy of Sciences Supervisor of the doctoral thesis: RNDr. Eduard Brynda, CSc., Institute of Macromolecular Chemistry, Czech Academy of Sciences Abstract: The application in medicine of label-free affinity biosensors, advanced implants, and blood-contacting devices requires that their surfaces resist non-specific protein adsorption (fouling) and associated complications in blood-derived fluids while displaying immobilized bioreceptors that provide specific biofunctionality. The aim of this thesis was to explore the strategies for the preparation of these antifouling bioactive surfaces. Various types of recently developed antifouling polymer brushes were synthesized and evaluated in terms of their ability to prevent fouling from blood plasma (obtained from various commercial sources and individual donors) as well as thrombus formation when contacted with whole blood. Moreover, single-cell force spectroscopy was utilized to characterize the bacterial adhesion force and energy on these polymer brushes, which were significantly reduced in comparison to various reference substrates. The immobilization of bioreceptors was tackled by means of a...
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Dynamics of drying of sessile droplets in dependence on the surface wettability
Štefaníková, Radka ; Kylián, Ondřej (advisor) ; Shukurov, Andrey (referee)
Wettability is one of the key parameters that govern interaction between solid objects and their surrounding environment. In this work wettability of two kinds of materials was investigated - untreated and plasma treated polyether ether ketone and nanostructured C:F thin films deposited either onto a smooth substrate or on substrates seeded with nanoparticles. In the first case the main focus was given to the evaluation of dependence of wettability and water droplet drying dynamics on the plasma treated PEEK on storage time. It was found that plasma treatment induces changes in surface morphology and in chemical composition that in turn results in dramatic increase of surface wettability as well as in alteration in drying dynamics. It was shown that whereas chemical composition and wettability gradually approach properties observed on untreated PEEK, the drying dynamics, namely disappearance of the constant contact angle phase, is temporally stable. In the second case the main emphasis was given to the investigation of the effect of surface nanoroughness and its character on wettability of produced samples. It was found that when the base layer was composed from nanoparticles of the same kind, the surfaces exhibited higher values of water contact angles as compared to C:F films deposited onto smooth...
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Thin films of plasma polymers as stable supports for biomedical applications
Gordeev, Ivan ; Shukurov, Andrey (advisor) ; Novák, Rudolf (referee) ; Pavlík, Jaroslav (referee)
Title: Thin films of plasma polymers as stable supports for biomedical applications Author: Ivan Gordeev Institute: Charles University in Prague, Department of Macromolecular Physics Supervisor of the doctoral thesis: Doc. Ing. Andrey Shukurov, Ph.D, Charles University in Prague, Department of Macromolecular Physics. Abstract: Plasma polymers have been widely considered for use as bio-active coatings. In biomedicine, the surfaces that withstand accumulation of biofilms are of particular importance. This thesis is focused on development of new plasma-based methods for deposition of bio-resistant (non-fouling) plasma polymers. Poly(ethylene oxide) was the subject material. R.f. magnetron sputtering, plasma-assisted thermal vapour deposition and amplitude modulated atmospheric pressure surface dielectric barrier discharge were the methods adapted to fabricate thin films with tunable chemical composition, cross-link density and biological response. A new insight was gained into the processes of plasma polymerization as well as into composition/structure relationship and its effect on biological properties of resultant films. Keywords: plasma polymerization, PEO, 'non-fouling' properties, protein adsorption, cell adhesion
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Nano-structured multicomponent plasma polymers for controlled immobilization of biomolecules
Melnichuk, Iurii ; Shukurov, Andrey (advisor) ; Čech, Vladimír (referee) ; Pavlík, Jaroslav (referee)
Title: Nano-structured multicomponent plasma polymers for controlled immobilization of biomolecules Author: Iurii Melnichuk Department / Institute: Department of Macromolecular Physics/Charles University Supervisor of the doctoral thesis: Doc. Ing. Andrey Shukurov, Ph.D. Abstract: The aim of this thesis is to highlight the feasibility of tailored nano- structures in functionalizing surfaces for biointerfacial interactions. Development of new techniques for the production of nanoscaled biomaterials can be of use in a variety of medical and biological applications, e.g. biosensors, microarrays, drug sensors, implants, blood-contacting devices. This thesis first examines the early stages of nano-structured thin film growth fabricated by vapor phase deposition of poly(ethylene). We discuss island growth within a framework of rate equation theory, dynamic scaling theory and capture zone distribution. In a second stage, we test dielectric barrier discharge to activate PE nano-pattern for covalent immobilization of proteins. Finally, we assess cell behavior on surfaces in dependence on morphology and the presence of cell adhesive protein tropoelastin. We employ plasma polymerization to produce ultrathin hydrocarbon layer capable of protein anchoring. The thesis findings for the first time manifest the critical...
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Sensitive Layers for Optical Biosensors and Protein Chips
Rodriguez Emmenegger, César ; Brynda, Eduard (advisor) ; Lynn, Nicholas Scott (referee) ; Shukurov, Andrey (referee)
Sensitive layers for optical biosensors and protein chips The goal of this thesis was the development of sensitive surfaces for optical affinity biosensors detecting in complex biological media. The practical application of these surface-based technologies has been hampered by protein fouling from biological media, in particular blood plasma, where the vast majority of relevant analytes are present. The work of the thesis was centred in three main foci: Design and preparation of antifouling and non-fouling surfaces Evaluation and conceptualisation of their resistance to fouling from blood plasma and serum as well as other biological fluids Preparation of sensitive layers for detection in complex biological media Three approaches were used to prepare protein resistance surfaces, i) ω-functional self-assembled monolayers (SAM), ii) end-tethered polymers and iii) polymer brushes prepared by surface initiated controlled radical polymerisation. Investigation of proteins in the blood plasma deposits on PEG- based surfaces revealed that some fouling is unavoidable in PEG-based surface modifications. A novel type of non-fouling polymer brushes based on poly[N-(2-hydroxypropyl) methacrylamide] challenged the accepted ideas for the design of protein resistant surfaces. For the first time a...
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Atomic Force Microscopy (AFM) used to reveal differences in the cell wall structure of of yound and old S. cerevisiae yeast cells.
Schwarzová, Tereza ; Plášek, Jaromír (advisor) ; Shukurov, Andrey (referee)
The main goal of this MSc. is to use Atomic Force Microscopy (AFM) in studies of yeast cell wall structure aimed at (i) expected differences between young and aged S. cerevisiae cells, (ii) the effects of glucose concentration in culthuring media on the quality of yeast cell wall. AFM can image biological systems with molecular resolution in real time, and under natural condition. Numerous AFM images of the surface of S. cerevisiae yeast cells (strains AD 1-3,IL,US and JC 482A, AD-JC 488A) have been obtained, which surpassed that one of standard results of still-rare AFM studies of yeast cells. No clear effect of glucose concentration has been found. On the other hand, AFM studies have revealed ageing-related changes in the structure of yeast cells (crumpling, rough surface). Highresolution images of yeast bud scars, including their fine details were also obtained.
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Nanostructured films based on plasma polymers
Solař, Pavel ; Shukurov, Andrey (advisor) ; Vyskočil, Jiří (referee)
In this thesis we have studied growth and properties of thin films prepared by tilted deposition using sputtering. The construction of low pressure magnetron is presented. The influence of deposition conditions on formation of columnar structure using scanning electron microscope was studied. Formation of columnar structures of metals, composites metal-plasma polymer and plasma polymer is described. The influence of deposition conditions on surface roughness obtained by AFM is discussed. Chemical structure of composite and plasma polymer films has been determined using XPS and infrared spectroscopy.
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