Dans cette thèse nous avons étudié la mise en forme de matériaux carbonés par des méthodes électrochimiques pour des applications dans les domaines des capteurs et de l’énergie. Dans la première partie, l’électrochimie bipolaire, qui permet de réaliser des réactions électrochimiques sur un objet conducteur présent dans une solution et soumise à un champ électrique, a été utilisée pour générer des objets de type Janus. Ces objets asymétriques ont été modifiés à une extrémité par du poly(N-isopropylacrylamide (pNIPAM), un hydrogel sensible à la température, et par une peinture électrophorétique à l’autre extrémité. En contrôlant l’intensité du champ électrique ainsi que son temps d’application il a été possible de varier la longueur ainsi que l’épaisseur de l’hydrogel. Ces objets sensibles à la température, émettant de la lumière, ont des applications potentielles dans le domaine des capteurs ou dans le milieu médical.Dans la seconde partie, la mise en forme de carbone poreux pour des applications électrochimiques a été étudiée. La carbonisation de polymères contenant du zinc a été utilisé pour synthétiser du carbone micro/mésoporeux possédant ainsi une grande surface spécifique. Les polymères contenant du zinc ont été préparés à partir de différents types de ligands d’acide dicarboxylique par une méthode solvothermique. Ils ont ensuite été carbonisés pour obtenir des matériaux poreux avec des caractéristiques et des propriétés particulières. Ils ont été utilisés comme matériaux d’électrode pour des supercondensateurs, montrant des capacités élevées. De plus ils possèdent également une activité électrocatalytique à la réaction de réduction de l’oxygène. / In this thesis, the design of advanced carbon materials via electrochemical techniques and for electrochemical applications have been studied. In the first part, the concept of bipolar electrochemistry, which allows carrying out electrochemical reactions on a free-standing conductive object in an electric field, was employed to generate Janus-type objects. These objects are modified with a thermoresponsive hydrogel of poly(N-isopropylacrylamide) (pNIPAM) on one side and an electrophoretic deposition paint (EDP) on the other side. The results show that the length and the thickness of the hydrogel can be controlled by varying the electric field and the time of the experiment. The concept can be further generalized to other micro- and nanometer-sized objects, thus opening up perspectives for various applications.In the second part, the design of porous carbon structures for electrochemical applications was studied. The direct carbonization of non-porous zinc containing polymers was used to synthesize micro/mesoporous carbons with high surface area, pore volume. Non-porous zinc containing polymers with various types of dicarboxylic acid ligands prepared by solvothermal method were used as templates and starting materials. After carbonization porous carbons with various characteristics and properties were obtained. The synthesized porous carbon samples showed good electrochemical performance with high capacitance values. In addition, the derived materials exhibit excellent electrocatalytic activity with respect to the oxygen reduction reaction (ORR).

<p>U ovom radu vr&scaron;ena su istraživanja u cilju razvoja novih postupaka sinteze za nekoliko vrsta polimernih mreža i hibridnih biopolimernih materijala za specijalne primene. Cilj je bio da se razvije novi postupak sinteze rotaksana na bazi poli(etilen glikola) i &beta;-ciklodekstrina kaoprekursora mreža. Dobijeni prekursori mreža iskori&scaron;ćeni su za sintezu topolo&scaron;kih gelova koji su umreženi preko hidroksilnih grupa ciklodekstrinskih prstena. Analiziran je i uticaj količine umreživača, odnosno gustine umreženja, na svojstva bubrenja. Proučavan je i uticaj nanopunila na svojstva modelnih epoksi mreža na bazi bisfenola A i poli(oksi propilen) diamina. Kao punila kori&scaron;ćene su nanočestice nemodifikovanog i povr&scaron;inski modifikovanog titanijum(IV)oksida (TiO₂). Dinamičko-mehaničkom analizom potvrđen je ojačavajući efekat punila. Razvijen je postupak sinteze poli(D,L-laktida) u mikrotalasnom polju, čime je drastično smanjeno vreme polimerizacije (sa 150 sati na 15 minuta) u odnosu na klasičnu termosintezu. Sintezom poli(laktida) kao i kopolimera poli(laktida) sa biorazgradivim monomerima (na osnovu obnovljivih sirovina) dobijeni su materijali izuzetnih ekolo&scaron;kih svojstava. Poli(laktid) se odlikuje veoma dobrim mehaničkim svojstvima i biorazgradivo&scaron;ću, dok je blok-kopolimerizacijom sa drugim biorazgradivim monomerima vr&scaron;ena sinteza termoplastičnih poliestara. Variranje dužine segmenata je ostvareno sintezom adekvatnih oligomera kao prekursora za kopolimerizaciju. Vr&scaron;eno je projektovanje sirovinskog sastava segmentiranih elastomera kod kojih postojanje mekih i tvrdih segmenata ima za posledicu mikrofaznu separaciju faza &scaron;to u toku eksploatacije utiče na mehanička svojstva i mogućnost III razgradnje. Na taj način dobijeni su elastomerni materijali željenih svojstava. Metodama FTIC i 1H NMR spektroskopijom potvrđena je pretpostavljena struktura segmenata i finalnih termoplastičnih poliestara. Analizom molskih masa poliestara metodama gel propusne hromatografije, viskozimetrije i osmometrije napona pare, potvrđena je izuzetna kontrola reakcija polimerizacije i uspe&scaron;nost primenjenih metoda sinteze. Analiza toplotnih svojstava blok poliestara diferencijalno skenirajućom kalorimetrijom je pokazala da zbog neme&scaron;ljivosti faza, tvrdih i mekih segmenata, finalni blok poliestri mogu da pokažu razlike u temperaturama faznih transformacija u zavisnosti od dužine i udela segmenata. Termogravimetrijskom analizom je potvrđen uticaj dužine segmenata i faznog razdvajanja na toplotna svojstva termoplastičnih poliestara. Očekuje se da će sintetisani materijali biti podesni za primene u inženjerstvu tkiva, a posebno kao materijali za kontrolisano otpu&scaron;tanje lekova.</p> / <p>The primary goal of the work described in this thesis was to develop new methods for the<br />synthesis of polymer networks and hybrid biopolymers for special applications. The purpose was a development of synthesis procedure for the preparation of rotaxane based on poly(ethylene glycol) and &beta;-cyclodextrin, as network precursors. These network precursors were then cross-linked through hydroxy groups on cyclodextrine rings. Polyrotaxanes are intermediary products in the synthesis of topological gels and they are formed by the insertion of the linear polymer chains of poly(ethylene oxide) into the &beta;-CD cavities. In this work polyrotaxanes from acetylated-&beta;-CD and poly(ethylene oxide) were synthesized. The influence of crosslinker contents, and crosslink density on swelling properties was investigated. The influence of synthesis parameters and filler modification on reactions and final properties of organic-inorganic hybrid materials based on epoxy resin and an organically modified titanium(IV)oxide (TiO2) was investigated. Dynamic-mechanical analysis was used to determine reinforcement effect of nanofiller on the epoxy resin properties. The aim of this work was the investigation of microwave irradiation on the polymerization of D,L-lactide. It was found that if heating is carried out in the microwave field polymerization time of D,Llactide rapidly decreases from 150 hours to 15 minutes. Environmentally friendly materials were obtained from poly(lactide) and copolymers of poly(lactide) and monomers based on renewable resources. Poly(lactide) is biocompatible and biodegradable polymer with high stretching and low extension capacities. It has been used for the production of orthopedic fraction fixators and sutures surgery. Poly(lactide) was used for thermoplastic polyester (TPE) synthesis. Most thermoplastic polyesters derive their properties from segmented or block structures which are achieved by alternating hard and soft segments. FT-IR and 1H NMR spectroscopy were confirmed the assumed structure of segments and final thermoplastic polyesters. Since the properties of these materials strongly depend on the degree of phase separation, the influence of the lenghts of soft and hard segment on final properties of obtained TPEs was studied. Analysis of molecular mass of these polyesters by gel permeation chromatography, vapor pressure osmometry and viscozimetric analysis confirmed that good control of polymerization was achieved and that synthesis methods were successful. Thermal properties were characterized by means of differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA). Phase separation had strong influences on thermal properties of obtained TPEs. DCS measurements showed that due to poor mixability of hard and soft segments, final block polyesters could have different temperatures of phase transitions depending on the length of the segments. Thermal degradation and the influence of phase separation on thermal stability of segmented thermoplastic polyesters were confirmed by nonisothermal analysis, using thermogravimetric analysis. It is expected that synthesized materials will be suitable for tissue engineering and as drug carriers.</p>

The aim of master thesis was to study structural and transport properties of PVA films modified with method of semi-IPN with suitable polyectrolytes and plasticizers. The first important step was optimalization of PVA films preparation, when time of heating was set at 90 °C for 1 hour. Drying was set at 50 °C for 24 hours. Molecular weight of PVA was chosen 85–124 kDa in concentration 10 wt.%. For preparation of PVA-based semi-IPN thin films polyelectrolytes (polyglutamic acid, DEAE-dextran hydrochloride) and plasticizer (glycerol) were selected. Basic characterization of prepared materials was performed with FTIR, TGA, SEM and specific surface analysis. The difference between modified PVA films was in the chargé of individual functional groups carried by used polyelectrolytes. Surfaces of all the PVA films were smooth without visible defects. Transport properties were characterized with the method of horizontal diffusion cell with methylen blue used as a probe. Diffusion coefficients of methylen blue through PVA films were determined. It was found, that the fastest pass was throw PVA film without additives. The slowest diffusion was observed through PVA/DEAE-dextran film, because of the same charge of the film with a probe. PVA/PGA reacted with methylen blue to form a complex. Plasticizer effect on the diffusion was only minor; it caused a slight decrease of diffusion coefficient. These films were easier to handle.

This diploma thesis deals with hyaluronan modified by palmitoyl and its gelation. Gels were created from palmitoyl hyaluronan with molecular weight 216 kDa and degree of substitution 11 % in concentrations 15 and 20 g dm-3 in water and concentrations 10, 15, 20 g dm-3 in NaCl and TSB. Also gel from palmitoyl hyaluronan with molecular weight 35 kDa and degree of substitution 10 % in concentrations 20, 30 g dm-3 in NaCl was created. Gels were investigated concerning medical applications. Gels were rigid and had very good properties, which was confirmed by rheology. The physical properties (pH, water content) of gels and stability were investigated. On the grounds of the MTT test, three methods of cell incorporation were suggested. Gels are nontoxic, biocompatible, and biodegradable with nontoxic degradation products and that is why they are excellent aspirants for use in biomedicine.

This diploma thesis investigates the suitability of relaxation tests as a part of complex characterization of hydrogel materials using classical rheology methods. With respect to the current research, creep and three interval thixotropy tests were taken into account. For them, general optimization was done aiming to find an ideal parameter settings. The optimization was performed using physically crosslinked agarose (AG) hydrogel and the tuned tests were also applied to two more samples: hyaluronan (HyA) and polyvinyl alcohol (PVAl) gel. These materials were selected due to their mutually different crosslinking principle. The experiments showed, the AG gel proved to have the best ability to recover after deformation of all studied samples. On the other hand, the HyA gel relaxed the worst. Although the final results of both tests were comparable, the regeneration process itself was different. Hence, the complex relaxation characteristics cannot be described using one of the performed tests alone and both the creep and three interval thixotropy tests have great importance in the scope of complex relaxation behaviour. The obtained results may lead to more precise description of deformation and relaxation, which are frequent phenomena occurring during treatment and application of hydrogel materials.

Tuberous sclerosis complex (TSC) is a multisystem tumor-forming disorder caused by biallelic inactivation of TSC1 or TSC2. The primary cause of mortality arises from mesenchymal manifestations in the lung and kidney: pulmonary lymphangioleiomyomatosis (LAM) and renal angiomyolipomas (RAMLs). Despite a well-described monogenic etiology, there remains an incomplete understanding of disease pathogenesis. Consequentially, tractable models which fully recapitulate disease characteristics are lacking. Here, I develop and study novel tissue-engineered models of TSC lung and kidney disease. In my first chapter, I demonstrate that lung-mimetic hydrogel culture of pluripotent stem cell-derived diseased cells more faithfully recapitulates human LAM biology compared to conventional culture on two-dimensional plastic. Leveraging this culture system, I conducted a three-dimensional drug screen using a custom 800-compound library, tracking cytotoxicity and invasion modulation phenotypes at the single cell level. I identified histone deacetylase (HDAC) inhibitors as a group of anti-invasive agents that are also selectively cytotoxic towards TSC2-/- cells. HDAC inhibitor therapeutic effects remained consistent in vivo upon xenotransplantation of LAM cellular models into zebrafish. In my second chapter, I develop a genetically-engineered human renal organoid model which recapitulates pleiotropic features of RAMLs in vitro and upon orthotopic xenotransplantation. I find that loss of TSC1/2 affects multiple developmental processes in the renal epithelial, stromal, and glial compartments. First, loss of TSC1/2 leads to an expanded stroma by favouring stromal cell fate acquisition and alters terminal stromal cell identity. Second, epithelial cells in the TSC1/2-/- organoids exhibit a rapamycin-insensitive epithelial-to-mesenchymal transition. Third, a melanocytic population forms exclusively in TSC1/2-/- organoids, branching from MITF+ Schwann cell precursors of a bona fide neural crest-to-Schwann cell differentiation trajectory. Through these two thesis chapters, I realize the power of tissue-engineered models for the study of TSC. This work offers novel insights into the pathogenesis of RAMLs and identifies a new class of therapeutics suitable for trialing in patients with pulmonary LAM.

For passive (classical) materials, stress and strain are used to extract the material behavior from the sample behavior in a tensile test. In analogy, the actuation behavior of active (smart) materials can be normalized. In the present research, we show the normalization using the example of hydrogels that react with a volume change (swelling and deswelling) when exposed to stimulus-changes like temperature, chemical concentrations, pH or light intensity changes. The normalized behavior can then be implemented with the Temperature-Expansion-Model which is based on the analogy of active behavior with thermal expansion. This allows the simulation of arbitrary active structures and the extraction of the sensitivity measure to a stimulus.

This thesis studies the properties and behaviour of phase-separated hydrogels prepared by interaction of hyaluronan with oppositely charged surfactants. Three representatives of surfactants, namely cetyltrimethylammonium bromide, chloride and p-toluensulfonate (CTAB, CTAC, CTAT), were selected for comparison. Using the method of rheology, the fact that the system of Hya-CTAT forms the most rigid hydrogels has been proved. Higher molecular weight of hyaluronan has also direct influence on the volume and stiffness of the newly formed hydrogels. Preparation methods were compared as well. Mixing the stock solutions of entry components appeard to be the most suitable. Small-angle X-ray scattering was used for determination of shape and size of surfactant's micelles, concluding that it has no effect on the volume of formed gels. The results of this study indicate that given gels are to a certain extent competitive and incorporation of hyaluronan into their structure is desirable with respect to its biological activity. This offers a potential usage of these substances in the field of medical applications.

This diploma thesis is focused on the determintaion of viscoelastic properties of agarose hydrogels containing different polyelectrolytes by microrheological and macrorheological techniques. From microrheological techniques the dynamic light scattering was used. Firstly, the influence of different polyelectrolyte volume was studied. Then the effect of variously charged polyelectrolyte and ionic strenght on microrheological properties of agarose hydrogels were determined. Classic rheology was used to compare the results obtained using the DLS microrheology method. Finally, the results from macro- and microrheology were correlated with each other.

This master's thesis is focused on study of transport processes in hydrogels based on humic acids. For this purpose is used methods unsteady diffusion in cuvettes, which was studied the transport of organic dyes, specifically methylene blue and rhodamine 6G, in agarose hydrogel without the addition and with the addition of individual standards humic acids (Leonardite, Elliott Soil, Suwannee River II and Pahokee Peat). This method is based on spectrophotometric monitoring of concentration changes of dyes depending on space of the cuvette and on time. The aim of this thesis was to investigate the effects of interactions between diffusing dye and the particular type of gel to the resultant effective diffusion coefficient of dye. The experiments indicate that the presence of humic acid in the hydrogel greatly affects the transport of selected dyes.