Hyaluronan is a chemical, which can be qualified as essential for vertebrates. It is a part of the extracellular matrix in most of tissues and also a major component of some other tissues. Besides of the mechanical functions this compound is important for many biological processes such as growth of tumor cells. The objective of this thesis was development of carrier systems containing native hyaluronan and hydrophobic drugs. For purposes of this work fluorescence probes (pyrene, prodan, perylene, DPH, mereocynine 540) instead of drugs were used. By using further mentioned sophisticated methods the properties of these systems were studied. The systems were prepared by freeze-drying. The effect of freeze-drying on support of interactions was observed by fluorescence spectrometry (steady-state and time-resolved). The stability of freeze-dried systems was determined by zeta potential, which was measured by electrophoretic light scattering. Cakes obtained by freeze-drying were analyzed by several methods. First one was effluence gas chromatography connected with FT-IR spectrometry. In this method the present of tertiary butyl alcohol in product was observed. The cakes were also analyzed by scanning electron microscopy, which can provide the information about the surface and elemental constitution of the material. The results of this work can shed light on the area of developing of drugs with targeted distribution of active compound.

In this thesis, we start with the description of the biophysical properties of the plasma membrane models upon signaling processess such as the increased cytoso- lic concentration of calcium ions, or posttranslational modifications of membrane proteins. Calcium signaling is characterized by a rapid increase of its cytosolic concentration. We identify calcium binding sites and characterize the binding in the plasma membrane models of increasing complexity from pure phospholipid bilayers, through cholesterol and peptide rich lipid membranes, to membranes ex- tracted from HEK293 cells. We use Time-Dependent Fluorescent Shift method, which provides direct information on hydration and mobility in defined regions of a lipid bilayer, accompanied with molecular dynamic (MD) simulations, which give molecular details of the studied interactions. The initial step of signaling mediated by PAG protein is its double palmi- toylation. We investigate changes of the biophysical properties of both the lipid membrane and the peptide itself upon the incorporation of the palmitoyls. Em- ploying all atom MD simulations, we study inter- and intramolecular interactions as well as changes in membrane hydration, thickness, or lipid ordering. The second part of the thesis, realized in a direct collaboration with a phar- macological...

The connection of molecular monomers through non-covalent interaction (e.g. hydrogen bonding, π-π interaction, coordination bonding) enables the formation of supramolecular polymers. The major advantage of these bonds is their reversibility and consequently their ability to self-assembly or to disconnect depending on given conditions. This thesis examines the self-assembly through quadruple hydrogen bonding, which is strong and the resulting structures stable. Ureidopyrimidinon A and aromatic amines were always used as the starting compound for the preparation of monofunctional and bifunctional ureidopyrimidinones.

Indiana University-Purdue University Indianapolis (IUPUI) / Articular cartilage is subjected to dynamic mechanical loading during normal daily activities. This complex mechanical loading, including cell deformation and interstitial fluid flow, affects chondrocyte mechano-chemical signaling and subsequent cartilage homeostasis and remodeling. Focal adhesion kinase (FAK) and Src are known to be main mechanotransduction proteins, but little is known about the effect of mechanical loading on FAK and Src under its varying magnitudes and types. In this study, we addressed two questions using C28/I2 chondrocytes subjected to the different types and magnitudes of mechanical loading: Does a magnitude of the mechanical loading affect activities of FAK and Src? Does a type of the mechanical loading also affect their activities? Using fluorescence resonance energy transfer (FRET)-based FAK and Src biosensor in live C28/I2 chondrocytes, we monitored the effects of interstitial fluid flow and combined effects of cell deformation/interstitial fluid flow on FAK and Src activities. The results revealed that both FAK and Src activities in C28/I2 chondrocytes were dependent on the different magnitudes of the applied fluid flow. On the other hand, the type of mechanical loading differently affected FAK and Src activities. Although FAK and Src displayed similar activities in response to interstitial fluid flow only, simultaneous application of cell deformation and interstitial fluid flow induced differential FAK and Src activities possibly due to the additive effects of cell deformation and interstitial fluid flow on Src, but not on FAK. Collectively, the data suggest that the intensities and types of mechanical loading are critical in regulating FAK and Src activities in chondrocytes.

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Les polymères conjugués semi-conducteurs sont des matériaux prometteurs pour des applications en optoélectronique et pour la fabrication de dispositifs de conversion d'énergie flexibles. Ils sont toutefois difficilement mis en forme en raison de la rigidité de leur structure. Le poly(3-hexylthiophène) (P3HT) est souvent utilisé comme polymère conjugué organique modèle. Sa mise en forme et ses propriétés peuvent être optimisées en l'incorporant dans une matrice polymère et en favorisant l’orientation moléculaire de ses chaînes. Cette orientation peut être induite dans un matériau lors de sa mise en forme, notamment lors de la préparation de fibres par électrofilage. Le projet vise à préparer des matériaux optimisant l'orientation du P3HT et à développer des outils pour caractériser l'organisation moléculaire du P3HT dans ces matériaux. Plus spécifiquement, la première étude consiste à comprendre l'effet de la matrice polymère sur le comportement du P3HT dans des nanofibres électrofilées. Celles-ci sont préparées en mélangeant le P3HT à une matrice polymère amorphe de poly(méthacrylate de méthyle) (PMMA) atactique ou fortement cristalline de poly(oxyde d'éthylène) (POE), et l’orientation des chaînes de P3HT est mesurée par spectroscopie Raman. Les résultats montrent que la capacité du POE à cristalliser, contrairement au PMMA, contraint les chaînes du P3HT à s'orienter le long de l’axe de la fibre, ce qui devrait améliorer ses propriétés de transport de charge. La calorimétrie différentielle à balayage et la microscopie optique et électronique à balayage permettent respectivement d'analyser les propriétés thermiques et d'imager la morphologie des nanomatériaux. La seconde étude est de développer une approche pour identifier la transition vitreuse du P3HT dans des nanofibres électrofilées et des impressions 3D composées d’un mélange P3HT-POE. Nous suivons alors l'évolution de l’état d'agrégation du P3HT par spectroscopie de fluorescence et le déplacement de sa bande Raman associée au mode d’élongation C=C sur une gamme de températures afin d'observer sa transition de phase vitreuse à l'échelle du nanoobjet individuel. Une preuve de concept est réalisée par des analyses sur des films minces à base de P3HT pour ensuite analyser les échantillons d’intérêt. Les résultats de spectroscopie Raman et de fluorescence sur les nanomatériaux de P3HT sont comparés aux analyses DSC sur les matériaux macroscopiques. Le projet améliorera d'une part notre capacité à caractériser les nanomatériaux de P3HT et, d'autre part, à en optimiser les propriétés. De manière plus générale, nos résultats conduiront à terme à une meilleure compréhension des relations structure-mise en forme-propriété-fonction des polymères conjugués, contribuant à la préparation de nouveaux matériaux électroniques organiques plus performants. / Conjugated polymers are promising semiconducting materials for applications in flexible optoelectronic and energy conversion devices. However, they are difficult to process because of the rigidity of their polymer backbone. Poly(3-hexylthiophene) (P3HT) is often used as a model organic conjugated polymer. Its processing and its properties can be improved by incorporating it into a polymer matrix and by favoring the molecular orientation of its chains. This orientation can be induced in a material during its processing, notably during the preparation of fibers by electrospinning. The project aims to prepare materials optimizing the orientation of P3HT and to develop tools to characterize the molecular organization of P3HT in these materials. More specifically, the first study consists of understanding the effect of the polymer matrix on the behaviour of P3HT in electrospun nanofibers. These nanofibers are prepared by mixing P3HT with an amorphous atactic poly(methyl methacrylate) (PMMA) or highly crystalline poly(ethylene oxide) (PEO) polymer matrix, and the orientation of the P3HT chains is measured by Raman spectroscopy. The results show that the capability of POE to crystallize, unlike PMMA, constrains the chains of P3HT to orient themselves along the fiber axis, which could improve its charge transport properties. Differential scanning calorimetry and optical and scanning electron microscopy make it possible, respectively, to analyze the thermal properties and to image the morphology of the nanomaterials. The second study is to develop an approach to identify the glass transition temperature of P3HT in electrospun nanofibers and 3D prints composed of a P3HT-PEO blend. We then follow the evolution of the aggregation state of P3HT by fluorescence spectroscopy and the shift of the Raman band associated with the C=C elongation mode over a range of temperatures to observe its glass transition temperature at the scale of the individual nanoobject. A proof of concept is first realized by carrying out analyses on thin films based on P3HT, followed by the analysis of the samples of interest. Raman and fluorescence spectroscopy results on P3HT-containing nanomaterials are compared to DSC analyses on macroscopic materials. The project will improve our ability to characterize P3HT nanomaterials and to optimize their properties. More generally, our results will ultimately lead to a better understanding of the structure-processing-property-function relationships of conjugated polymers, contributing to the preparation of new, more efficient organic electronic materials.

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