Les micelles polyioniques ont émergé comme des systèmes prometteurs de relargage de médicaments hydrophiles ioniques. Le but de cette étude était le développement des micelles polyioniques à base de dextrane pour la relargage de médicaments hydrophiles cationiques utilisant une nouvelle famille de copolymères bloc carboxymethyldextran-poly(éthylène glycol) (CMD-PEG). Quatre copolymères CMD-PEG ont été préparés dont deux copolymères identiques en termes de longueurs des blocs de CMD et de PEG mais différent en termes de densité de charges du bloc CMD; et deux autres copolymères dans lesquels les blocs chargés sont les mêmes mais dont les blocs de PEG sont différents. Les propriétés d’encapsulation des micelles CMD-PEG ont été évaluées avec différentes molécules cationiques: le diminazène (DIM), un médicament cationique modèle, le chlorhydrate de minocycline (MH), un analogue semi-synthétique de la tétracycline avec des propriétés neuro-protectives prometteuses et différents antibiotiques aminoglycosidiques. La cytotoxicité des copolymères CMD-PEG a été évaluée sur différentes lignées cellulaires en utilisant le test MTT et le test du Bleu Alamar. La formation de micelles des copolymères de CMD-PEG a été caractérisée par différentes techniques telles que la spectroscopie RMN 1H, la diffusion de la lumière dynamique (DLS) et la titration calorimétrique isotherme (ITC). Le taux de relargage des médicaments et l’activité pharmacologique des micelles contenant des médicaments ont aussi été évalués. Les copolymères CMD-PEG n'ont induit aucune cytotoxicité dans les hépatocytes humains et dans les cellules microgliales murines (N9) après 24 h incubation pour des concentrations allant jusqu’à 15 mg/mL. Les interactions électrostatiques entre les copolymères de CMD-PEG et les différentes drogues cationiques ont amorcé la formation de micelles polyioniques avec un coeur composé du complexe CMD-médicaments cationiques et une couronne composée de PEG. Les propriétés des micelles DIM/CMDPEG ont été fortement dépendantes du degré de carboxyméthylation du bloc CMD. Les micelles de CMD-PEG de degré de carboxyméthylation du bloc CMD ≥ 60 %, ont incorporé jusqu'à 64 % en poids de DIM et ont résisté à la désintégration induite par les sels et ceci jusqu'à 400 mM NaCl. Par contre, les micelles de CMD-PEG de degré de carboxyméthylation ~ 30% avaient une plus faible teneur en médicament (~ 40 % en poids de DIM) et se désagrégeaient à des concentrations en sel inférieures (∼ 100 mM NaCl). Le copolymère de CMD-PEG qui a montré les propriétés micellaires les plus satisfaisantes a été sélectionné comme système de livraison potentiel de chlorhydrate de minocycline (MH) et d’antibiotiques aminoglycosidiques. Les micelles CMD-PEG encapsulantes de MH ou d’aminoglycosides ont une petite taille (< 200 nm de diamètre), une forte capacité de chargement (≥ 50% en poids de médicaments) et une plus longue période de relargage de médicament. Ces micelles furent stables en solution aqueuse pendant un mois; après lyophilisation et en présence d'albumine sérique bovine. De plus, les micelles ont protégé MH contre sa dégradation en solutions aqueuses. Les micelles encapsulant les drogues ont maintenu les activités pharmacologiques de ces dernières. En outre, les micelles MH réduisent l’inflammation induite par les lipopolysaccharides dans les cellules microgliales murines (N9). Les micelles aminoglycosides ont été quant à elles capable de tuer une culture bactérienne test. Toutefois les micelles aminoglycosides/CMDPEG furent instables dans les conditions physiologiques. Les propriétés des micelles ont été considérablement améliorées par des modifications hydrophobiques de CMD-PEG. Ainsi, les micelles aminoglycosides/dodecyl-CMD-PEG ont montré une taille plus petite et une meilleure stabilité aux conditions physiologiques. Les résultats obtenus dans le cadre de cette étude montrent que CMD-PEG copolymères sont des systèmes prometteurs de relargage de médicaments cationiques. / Polyion complex (PIC) micelles have emerged as promising delivery systems of ionic hydrophilic drugs. It was the aim of this study to develop dextran-based PIC micelles for the delivery of hydrophilic cationic drugs using a new family of carboxymethyldextranblock- poly(ethylene glycol) (CMD-PEG) copolymers. Four CMD-PEG copolymers were prepared: (i) two copolymers identical in terms of the length of CMD and PEG blocks, but different in terms of the charge density of the CMD block; and (ii) two copolymers in which the charged block is the same, but the PEG block is of different molecular weight. The micellization of CMD-PEG copolymers and drug delivery aspects of the resulting micelles were evaluated using different cationic drugs: diminazene (DIM), a model cationic drug, minocycline hydrochloride (MH), a semisynthetic tetracycline antibiotic with promising neuroprotective properties and different aminoglycoside antibiotics. The cytotoxicity of CMD-PEG copolymers was evaluated in different cell lines using MTT and Alamar blue assays. CMD-PEG micelles encapsulating different drugs were characterized using different techniques, such as 1H NMR spectroscopy, dynamic light scattering (DLS), and isothermal titration calorimetry (ITC). The pattern of drug release and pharmacological activity of micelles-encapsulated drugs were also evaluated. The CMD-PEG copolymers did not induce cytotoxicity in human hepatocytes and murine microglia (N9) in concentrations as high as 15 mg/mL after incubation for 24 h. Electrostatic interactions between CMD-PEG copolymers and different cationic drugs triggered the formation of PIC micelles with a CMD/drug core and a PEG corona. The properties of DIM/CMD-PEG micelles were strongly dependent on the degree of carboxymethylation of the CMD block. Micelles of CMD-PEG copolymers having degree of carboxymethylation ≥ 60%, incorporated up to 64 wt% DIM, resisted salt-induced disintegration in solutions up to 400 mM NaCl and sustained DIM release under physiological conditions (pH 7.4, 150 mM NaCl). In contrast, micelles of CMD-PEG of degree of carboxymethylation ~ 30% had lower drug content (~ 40 wt% DIM) and disintegrated at lower salt concentration (∼ 100 mM NaCl). The CMD-PEG copolymer that showed the most satisfactory micellar properties, in terms of high drug loading capacity, sustained drug release and micelles stability was selected as a potential delivery system of minocycline hydrochloride (MH) and different aminoglycosides. CMD-PEG micelles encapsulating either MH or aminoglycosides had small size (< 200 nm in diameter), high drug loading capacity (≥ 50 wt% drug) and sustained drug release. These micelles were stable in aqueous solution for up to one month, after freeze drying and in the presence of bovine serum albumin. Furthermore, the micelles protected MH against degradation in aqueous solutions. Micelles-encapsulated drugs maintained their pharmacological activity where MH micelles reduced lipopolysaccharides-induced inflammation in murine microglia (N9) cells. And aminoglycosides micelles were able to kill a test micro-organism (E. coli X-1 blue strain) in culture. Aminoglycosides/CMD-PEG micelles were unstable under physiological conditions. Micelle properties were greatly enhanced by hydrophobic modification of CMD-PEG. Thus, aminoglycosides/dodecyl-CMD-PEG micelles showed smaller size and better stability under physiological conditions. The results obtained in this study show that CMD-PEG copolymers are promising delivery systems for cationic hydrophilic drugs.

Made available in DSpace on 2016-06-02T19:55:41Z (GMT). No. of bitstreams: 1 6385.pdf: 11264050 bytes, checksum: cd77b4a424829bd8ae1b48ccd53f5616 (MD5) Previous issue date: 2014-10-08 / Introduced during the colonial period in Brazil, nowadays sugar cane is one of the main crops of the country's economy, generating more than 2 billion dollars per year in the Brazilian trade balance. Despite the benefits of expanding the sugarcane sector every year, the environmental impacts caused by burning straw cane sugar made the State of São Paulo Government create the Protocol of Agro-Environmental Cooperation in 2007, which aims the total elimination of cane burning by 2017. However, when the sugar cane stops being burned, some components of the plant, which remained in the field due to the burning, will start being in larger quantities in the process, and the effects of this future reality in sugar quality have not been studied In this doctoral thesis, the two components of great impact on the specifications or quality of the sugar were chosen: starch and dextran which were studied in the crystallization unit operation (by controlled cooling and vacuum evaporation), so that the impact on the final product (sugar) were evaluated. This current study used a reponse surface methodology, with 2 levels (309 and 1062 ppm), two factors (dextran and starch), 3 center points (one central point in triplicate) and 4 axial points, totaling 11 trials per type of crystallization. The experiments were conducted with sugar Type 2 solutions contaminated with starch and dextran, in an agitated and jacketed crystallizer (8 liters) in the laboratory. When the crystallization was performed, the matters were centrifuged, the sugars were separated from the honeys, and forwarded to the physico-chemical, textural and optical microscopy analyzes. In relation to the physicochemical analyzes of sugar, starch and dextran contamination interfered directly in the responses: starch, dextran, color, turbidity and alcoholic floc in both crystallization techniques, however, the controlled cooling under the same conditions of contamination (0-2000 ppm), presented sugars to lower rates, which kept the product according to the market specifications. The results of grain size analysis showed frequency curves with accumulation of smaller crystals at the opening of 0.5 mm, according to the increase of dextran in the tests. And the optical microscopy analysis identified the existence of a relationship between the amount of contaminants, and the appearance of agglomerated crystals, besides "needle-like" crystals were not observed. The experimental chosen design collaborated in the identification of starch and dextran agents, in the increase or decrease of the analyzed responses, besides suggesting the collaboration of the combined effect on the quality of sugar. Concerning the product quality, the use of crystallization technique by controlled cooling proved to be the most suitable in the reduction of contaminants in the sugar, particularly in solutions containing 2,000 ppm of dextran and starch. Given the crop of sugarcane in the coming years, and that the contamination of dextran and starch may be higher than those found in syrups of industrial processes currently, this work may contribute to the knowledge of the contaminants and their combined actions in the crystallization and in understanding of the differences in the product quality. / Introduzida no período colonial no Brasil, a cana-de-açúcar é hoje uma das principais culturas da economia do país, gerando mais de 2 bilhões de dólares por ano na balança comercial brasileira. Apesar dos benefícios da expansão do setor sucroalcooleiro a cada ano, os impactos ambientais causados pelas queimadas da palha de cana-de-açúcar, levaram o Governo Estadual Paulista a criar em 2007, o Protocolo de Cooperação Agroambiental, que visa a eliminação total da queima de cana até 2017. No entanto, quando a cana-de-açúcar deixar de ser queimada, alguns componentes da planta que ficavam no campo com a queima passarão a entrar no processo em maiores quantidades, e os efeitos dessa futura realidade na qualidade do açúcar ainda não foram estudados. Nesse trabalho de doutorado, foram escolhidos dois componentes de grande impacto nas especificações ou qualidade do açúcar: o amido e a dextrana, os quais foram estudados na operação unitária de cristalização (por resfriamento controlado e por evaporação a vácuo), para que o impacto no produto final (açúcar) fosse avaliado. O presente trabalho utilizou um delineamento composto rotacional, com 2 níveis (309 e 1062 ppm), dois fatores (dextrana e amido), 3 pontos centrais (1 ponto central em triplicata) e 4 axiais, totalizando 11 experimentos por tipo de cristalização. Os experimentos foram realizados com soluções de açúcar Tipo 2, contaminadas com amido e dextrana, em um cristalizador agitado e encamisado (8 litros), em laboratório. Realizadas as cristalizações, as massas foram centrifugadas, e os açúcares separados dos méis, e encaminhados para as análises físico-químicas, granulométricas e de microscopia óptica. Em relação às análises físico-químicas do açúcar, as contaminações de dextrana e amido interferiram diretamente nas respostas: amido, dextrana, cor, floco alcoólico e turbidez, nas duas técnicas de cristalização, no entanto, o resfriamento controlado, nas mesmas condições de contaminação (0 a 2000 ppm), apresentou açúcares com os menores índices, o que manteve o produto nas especificações do mercado. Os resultados das análises granulométricas demonstraram curvas de frequência com acúmulo de cristais menores na abertura de 0,5 mm, conforme o aumento de dextrana nos testes. E as análises de microscopia óptica identificaram a existência de uma relação entre a quantidade de contaminantes, e o aparecimento dos cristais aglomerados, além de não serem observados cristais tipo agulha . O planejamento experimental adotado colaborou na identificação dos agentes amido e dextrana, no aumento ou na diminuição das respostas analisadas, além de sugerir a colaboração do efeito combinado desses na qualidade do açúcar. Em termos de qualidade do produto, a aplicação da técnica de cristalização por resfriamento controlado mostrou-se mais indicada na redução dos contaminantes no açúcar, principalmente em soluções com 2000 ppm de dextrana e amido. Tendo em vista a colheita de cana crua nos próximos anos, e que as contaminações de dextrana e amido poderão ser superiores as encontradas nos xaropes dos processos industriais hoje, o presente trabalho pode contribuir no conhecimento dos contaminantes e de suas ações combinadas na cristalização, e no entendimento das diferenças na qualidade do produto.

Des nanocapsules (NCs) biocompatibles destinées à l’administration intraveineuse d’agents anticancéreux hydrophobes ont été élaborées par polymérisation RAFT en miniémulsion, confinée à l’interface liquide/liquide. La polymérisation RAFT a été utilisée pour contrôler la croissance des greffons polymères constituant l’écorce des NCs à partir d’un transurf (macroagent RAFT et tensioactif) multifonctionnel dérivé du dextrane (DexN3-τCTAγ). Des NCs constituées d’une écorce en polymère hydrophobe (poly(méthacrylate de méthyle)) entourant un cœur liquide huileux (Miglyol®810) et recouvertes d’une couronne hydrophile polysaccharide (dextrane) ont ainsi été obtenues. Ces nano-objets ont été caractérisés en termes de taille, de recouvrement en dextrane (quantité de polysaccharide, épaisseur et stabilité), de stabilité colloïdale et de morphologie. La fabrication de NCs à écorce polymère pH-sensible a également été abordée. Enfin, le potentiel biomédical de ces nano-objets a été évalué grâce à différentes études : i) encapsulation et libération d’une substance active modèle, ii) cytotoxicité de NCs, iii) interactions des NCs avec les protéines plasmatiques et iv) fonctionnalisation de la surface des NCs par chimie « click ». / Biocompatible nanocapsules (NCs) for intravenous administration of hydrophobic anticancer agents were produced by interfacial Reversible Addition-Fragmentation chain Transfer (RAFT) miniemulsion polymerization. Controlled growth of polymeric grafts constituting NCs shell was obtained using a multi-reactive dextran-based transurf called DexN3-τCTAγ (acting both as macroRAFT agent and surfactant) to mediate RAFT polymerization at the liquid/liquid interface. NCs composed of a hydrophobic polymer shell (poly(methyl methacrylate)), an oily liquid core (Miglyol®810) and a hydrophilic polysaccharide coating (dextran) were obtained. These nano-objects were characterized in terms of size, dextran coverage (density, thickness and stability), colloidal stability and morphology. Synthesis of NCs with a pH-sensitive polymer shell was approached. Finally, potential of these nano-objects for biomedical applications was evaluated by studies on different aspects: i) encapsulation and delivery of a model active substance, ii) NCs cytotoxicity, iii) NCs interactions with plasma proteins, and iv) surface functionalization of NCs by “click chemistry”.

Des glycopolymères greffés et dibloc, amphiphiles et photosensibles, à base de poly(acrylate d'o-nitrobenzyle) (PNBA) hydrophobe et photoclivable et de dextrane hydrophile ont été préparés avec succès en utilisant notammennt une réaction d'Huisgen (Cycloaddition Azoture-Alcyne catalysée par le Cuivre (I) - CuAAC chimie click). Dans un premier temps, la polymérisation de l'acrylate d'o-nitrobenzyle a été contrôlée avec succès grâce aux développements récents de la polymérisation radicalaire vivante par transfert d'un seul électron (SET-LRP). Nous avons alors obtenu un PNBA fonctionnalisé à son extrémitié par un brome. Ce brome a ensuite été substitué par un groupe azido. En parallèle, le dextrane a été modifié pour y introduire plusieurs fonctions alcyne (dextrane alcyne) ou une seule sur son extrémité réductrice (dextrane α-alcyne). Nous avons ensuite fait réagir ces dérivés de dextrane avec le PNBA-N3 pour obtenir respectivement les glycopolymères greffés et dibloc. Tous les glycopolymères ont été caractérisés par chromatographie d'exclusion stérique (SEC), Résonnance Magnétique Nucléaire 1H, 13C, 2D DOSY 1H et par spectrométrie FT-IR. Dans un deuxième temps, nous avons optimisé les conditions pour obtenir des nanoparticules peu disperses à partir des précédents glycopolymères. Dans certains cas, des nanoparticules ont également été obtenues en utilisant le dextrane alcyne et le PNBA-N3 dans un procédé d'émulsion/évaporation de solvant organique. La stabilité de toutes les nanoparticules vis-à-vis de solutions aqueuses de diverses forces ioniques ou d'un tensioactif compétitif a été étudiée. Enfin, l'effet de la lumière sur ces nanoparticules photosensibles a été mis en évidence à l'aide de la lampe UV. Plus précisément, nous avons pu suivre la destruction des nanoparticules par spectroscopie de fluorescence et diffusion de lumière dynamique en encapsulant le Rouge du Nil (sonde fluorescente) au sein de ces particules / Photosensitive grafted and diblock amphiphilic glycopolymers based on hydrophobic photosensitive poly(o-nitrobenzyl acrylate) (PNBA) and hydrophilic dextran were successfully prepared via grafting onto techniques through a Huisgen-type Copper(I) catalyzed Azide-Alkyne Cycloaddition (CuAAC click chemistry). Firstly, recent developments in the single-electron transfer–living radical polymerization (SET–LRP) provided us an access to control the o-nitrobenzyl acrylate polymerization and we obtained PNBA with bromide end function. Then, this bromide end function was replaced by azido (N3) group. In a parallel way, we modified dextran by introducing several alkyne groups all long the polysaccharide chain (alkynated dextran) or only one group at the reducing end-chain (α-alkyne dextran). In the second step, alkynated dextran and α-alkyne dextran were reacted with PNBA-N3 by CuAAC to obtain grafted or diblock glycopolymers. All glycopolymers were characterized by Size Exclusion Chromatography, 1H, 13C, 2D DOSY 1H NMR and FT-IR spectroscopy. Secondly, conditions to formulate nanoparticles from the previous glycopolymers were optimized. In some case, we also carried out an emulsion/evaporation process using dextran alkynated and PNBA-N3 to produce nanoparticles. Then, stability of nanoparticles were studied over rang of ionic strengths as well as stability in presence of a competitive surfactant. Finally, the effect of light on these photosensitive nanoparticles was studied using UV-lamp. More precisely, we loaded these nanoparticules by Nile Red fluorescent dye and followed thier destruction by using fluorescence spectroscopy and Dynamic Light Scattering

This work deals with the current topic of carrier systems. Since the biggest problem is the passage of hydrophobic drugs through the bloodstream, or through universal body barriers (eg blood-brain), it is necessary to chemically modify these carriers in order to be able to administer hydrophobic substances effectively. Based on a literature search, several systems are designed and subsequently studied, in which there is a presumption of possible use for carrier systems and at the same time they have biosurfactants incorporated in them due to their ability to solubilize hydrophobic molecules. The theoretical part of this work will describe the individual biosurfactants, the process of their production, their physicochemical properties, and the possibility of their use in carrier systems. At the same time, the individual carrier systems, the procedure of their preparation, the possibilities of their use are described, and their advantages and disadvantages are also compared. In the practical part, the screening of both individual substances and their mutual interactions, as well as methods used to study the emerging structures is then performed. The study of molecular interactions is primarily performed using the technique of dynamic light scattering. The next part describes the optimization of hydrogel formation with incorporated biosurfactants in their structure and then the formed gels are subjected to rheological and solubilization tests. The study of the internal structure of these gels is performed using a scanning electron microscope.

Staphylococcus aureus a été classé parmi les bactéries les plus pathogènes du genre Staphylococcus. Ce pathogène est responsable d'infections localisées (plaies chroniques, infections sur prothèses) voire de septicémies et d’infections nosocomiales. L’objectif principal de ce projet est d’élaborer des vecteurs colloïdaux biocompatibles à base de polysaccharides, chargés en principe actif antibactérien, et ciblant spécifiquement des biofilms de S. aureus. La méthode de complexation polyélectrolytes entre polysaccharides de charge opposée (chitosane/alginate et chitosane/dextrane sulfate) a été sélectionnée pour élaborer des particules de taille micrométrique. Ces microparticules n’étant pas stables, elles ont été stabilisées par réticulation chimique. Un antibiotique à large spectre d’activité de la famille des fluoroquinolones, la ciprofloxacine, a été séquestrée dans les microparticules. Des essais microbiologiques ont été réalisés en planctonique et sur biofilms, sur une souche de S. aureus et une souche de Pseudomonas aeruginosa. La ciprofloxacine encapsulée présente une activité antibactérienne (CMI, CMB et CMEB) plus importante que la ciprofloxacine libre. Par ailleurs, les MPs à base de chitosane/alginate sont plus actives que celles constituées de chitosane/dextrane sulfate. Enfin, un greffage d’un anticorps anti-protéine A a été réalisé sur les microparticules chitosane/alginate chargées en ciprofloxacine. Ces microparticules présentent une activité antibactérienne sur le biofilm de S. aureus légèrement améliorée par rapport aux microparticules dépourvues d’anticorps. / Staphylococcus aureus has been classified as one of the most pathogenic bacteria of the Staphylococcus genus. This bacterium is responsible for localized infections (chronic wounds, infections on artificial joints) or even septicemia and nosocomial infections. The main objective of this project is to develop biocompatible colloidal vectors based on polysaccharides, loaded with antibacterial active compound, and specifically targeting Staphylococcus aureus biofilms. The polyelectrolyte complexation between polysaccharide of opposite charge (chitosan / alginate and chitosan / dextran sulfate) has been selected to produce micrometric particles. By varying the total concentration of polysaccharide and the charge ratio between polyanion and polycation, it is possible to obtain variable sizes. As these microparticles were not stable, they were stabilized by chemical crosslinking. An antibiotic of the fluoroquinolone family, ciprofloxacin, with a large spectrum of activity, was entrapped in the micoparticles. Microbiological tests were carried out in planktonics and biofilms on different strains of Staphylococcus aureus and Pseudomonas aeruginosa. Loaded ciprofloxacin exhibits greater antibacterial activity (MIC, CMB and CMEB). Moreover, the chitosan / alginate-based MPs are more active than those consisting of chitosan / dextran sulfate. Finally, a grafting of an antiprotein A antibody was carried out on chitosan / alginate microparticles loaded with ciprofloxacin. These modified microparticles exhibit a slightly improved antibacterial activity compared to loaded ciprofloxaxin microparticles whitoutantibody.

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Denna avhandling presenterar experimentella studier av polyelektrolytadsorption på motsatt laddade ytor, där substrat av både kiseloxid och blekt barrsulfatmassa har använts. Ett huvudsakligt syfte med denna forskning var att karaktärisera konformationen hos adsorberade skikt av katjonisk polyakrylamid (CPAM) i jämförelse med katjonisk dextran (Cdextran) och relatera denna information till inbindningskapaciteten av kolloidal kiselsyra. Ett andra syfte i denna avhandling var att studera kinetiken för sekventiell adsorption av polyamidamin epiklorhydrin (PAE) och karboxymetyl cellulosa (CMC) på massafibrer och att bestämma adsorptionsisotermer för deponering av polyelektrolyter skikt för skikt på massafibrer. Adsorptionen av CPAM på kiseloxidytor studeras med stagnationspunkts-reflektometri och kvartskristalls-mikrogravimetri för att bestämma adsorptionskinetiken och mättnadsadsorptionens beroende av polyelektrolytens laddningstäthet, pH och NaCl koncentration. Konformationen hos adsorberade skikt av CPAM och Cdextran bestämdes både före och efter sekundär tillsats av kolloidal kiselsyra (CS) och adsorptionen av CS kvantifierades också som funktion av yttäckningen av polyelektrolyt. Resultaten indikerar att laddningstätheten hos CPAM kontrollerar den adsorberade mängden på kiseloxidytor vid låga NaCl koncentrationer. Både adsorptionen av CPAM och Cdextran på kiseloxid visades vara effektiv i NaCl koncentrationer upp till 1 M, vilket indikerar ett signifikant bidrag av icke-jonisk interaktion mellan polyelektrolyterna och kiseloxid. Adsorptionen av CS var högre på föradsorberad CPAM än Cdextran. Konformationen hos de adsorberade skikten efter tillsats av CS sågs expandera signifikant för skikt baserade på CPAM medan skikt av Cdextran vid låga salthalter verkade återta sin konformation efter en temporär expansion. I den andra delen av avhandlingen studerades sekventiell adsorption av PAE och CMC på massafibrer. Adsorptionsisotermer skikt för skikt på avkryllad massa visade att PAE adsorberade i större mängd än CMC, både i hänseende av massa och laddning. Adsorptionen av PAE var signifikant långsammare än CMC och adsorptionstiden till 90% av mättnadsadsorptionen bestämdes till 3 respektive 1 minut. Zetapotentialen för kryll bestämdes för adsorption av de två första polyelektrolytskikten och resultaten tydde på att kryllmaterialet omladdade inom en minut efter tillsatserna av polyelektrolyt. Reflektometriförsök inom sekventiell adsorption av PAE och CMC på kiseloxid antydde att den låga molekylviktsfraktionen av PAE störde uppbyggnaden av polyelektrolyt-multiskikten. / This thesis presents experimental studies of polyelectrolyte adsorption on oppositely charged surfaces, where substrates of both silica and bleached softwood kraft pulp were used. A major aim of this research was to characterise the conformation of adsorbed layers of cationic polyacrylamide (CPAM), in comparison to cationic dextran (Cdextran), and relate this information to the binding capacity of colloidal silica. A second aim in this thesis was to study the kinetics of the sequential adsorption of polyamide epichlorohydrine (PAE) and carboxymethyl cellulose (CMC) on pulp fibres, and to determine the adsorption isotherms for the layer-by-layer deposition of polyelectrolytes on pulp fibres. The adsorption of CPAM on silica surfaces was studied using stagnation point adsorption reflectometry and quartz crystal microgravimetry to determine its adsorption kinetics as well as the dependencies of polyelectrolyte charge densities, pH, and NaCl concentration on saturation adsorption. The conformation of adsorbed layers of CPAM and Cdextran, analysed in terms of amount of water and layer thickness, was determined both before and after the secondary adsorption of colloidal silica (CS), and the adsorption of CS was also quantified as a function of the surface coverage of the polyelectrolyte. Results indicate that the charge density of CPAM controlled the amount of the polyelectrolyte adsorbed on silica surfaces at low NaCl concentrations. The adsorption of both CPAM and Cdextran on silica was shown to be effective at up to 1 M NaCl concentrations, which indicates that non-ionic interactions between the polyelectrolytes and silica contribute significantly. CS adsorption was higher on pre-adsorbed CPAM than on Cdextran. The conformation of the adsorbed layer after CS addition was seen to expand significantly in CPAM-based layers, while the Cdextran layer appeared to restore its conformation after a temporary expansion at low salt concentrations. In the second part of the thesis, the sequential adsorption of PAE and CMC on pulp fibres was determined using the polyelectrolyte titration technique. Layer-by-layer adsorption isotherms derived on fractionated pulp showed that PAE adsorbed in higher amounts than CMC did, both in terms of adsorbed mass and adsorbed charge. The adsorption of PAE was significantly slower compared to CMC, and the adsorption times required to reach 90% of the saturation adsorption were 3 and 1 min, respectively. The zeta potential of pulp fines was determined for the adsorption of the two first polyelectrolyte layers, and data indicated that the fines recharge within one minute after the polyelectrolyte additions. Reflectometry experiments regarding the sequential adsorption of PAE and CMC on silica indicated that the low-molecular-weight fraction of PAE disturbed the formation of polyelectrolyte multilayers. / QC 20101112

De nouveaux glycopolymères greffés aux paramètres macromoléculaires contrôlés [dextrane-g-poly(acrylate de diéthylène glycol cholestéryle), Dex-g-PADEGChol] ont été préparés en quatre étapes via la stratégie de synthèse « grafting from». L'originalité de ces glycopolymères réside dans la combinaison, et pour la première fois, d'une dorsale polysaccharide hydrophile biocompatible/ biodégradable et de greffons polymères hydrophobes à caractère mésogène. L'ATRP a été utilisée pour contrôler la croissance des greffons PADEGChol en milieu homogène à partir d'un macroamorceur dérivé de dextrane (DexAcBr). Les conditions de polymérisation avaient été préalablement ajustées en étudiant l'homopolymérisation du monomère ADEGChol en présence d'un amorceur modèle et de plusieurs systèmes catalytiques CuIBr/(PMDETA ou OPMI) dans différents solvants (THF ou toluène). Le caractère amphiphile de ces glycopolymères a été évalué et leurs propriétés mésomorphes ont été étudiées par calorimétrie différentielle à balayage, microscopie optique à lumière polarisante et par diffraction des rayons X. Des études préliminaires par microscope électronique à transmission et diffusion dynamique de la lumière polarisée ont démontré que ces glycopolymères adoptent une morphologie vésiculaire appelée « polymersome » en phase aqueuse, lorsque le DMSO est utilisé comme co-solvant. Ces nano-objets pourront être testés ultérieurement pour la formulation d'un nouveau type de vecteurs de principes actifs / New graft glycopolymers with well-defined parameters [dextran-g-poly(diethylene glycol cholesteryl ether acrylate) (Dex-g-PADEGChol)] have been prepared in four steps using the "grafting from" strategy. Challenge of this work arises from the combination for the first time of a hydrophilic, biocompatible/biodegradable polysaccharide backbone with mesogen hydrophobic polymeric grafts. Controlled growth of the grafts (PADEGChol) was obtained using ATRP initiated in homogeneous medium from a dextran derivative (DexAcBr). In order to find the best polymerization conditions, homopolymerization of ADEGChol monomer was investigated using an initiator model and various catalytic systems CuIBr/(PMDETA or OPMI) in two solvents (Toluene and THF). The amphiphilic properties of such glycopolymers were evaluated and their mesomorphic properties have been studied by thermal polarizing optical microscopy, differential scanning calorimetry and X-ray scattering. Using transmission electron microscopy and dynamic light scattering, vesicular morphology called "polymersome" was observed in aqueous medium when DMSO was used as co-solvent. These polymersomes could be tested as new drug delivery systems