Synthesis of novel amphiphilic copolymers based on sugar moieties: development of new architectures and biomedical applications As early as in the 50’s, amphiphilic copolymers started to attract much interest in the frame of polymer science thanks to their self-assemblies as organized nano-structures in a selective solvent. The resulting micelles or vesicles have emerged as potentially useful materials in the biomedical field such as drug delivery systems when matching the specific conditions of size, coating nature and functionalization,… Moreover, active cell-targeting increases the therapeutic effect by selectively delivering the drug to the required cells. Accordingly, carbohydrates have drawn much attention due to the cell recognition processes they can mediate. Carbohydrates are thus incorporated in polymer backbones to mimic the naturally occurring substrate for the adapted cell receptors. The originality of this thesis is based on the use of sugar moieties as potential multi-hydroxylated initiators for the polymerization of various lactones. This leads to well-defined amphiphilic polymer architectures along with the development of a more facile route for the incorporation of carbohydrates in polymer chains to promote active cell-targeting of the as-obtained nano-structures. The first part of the thesis aims at describing the synthesis of novel amphiphilic brush-like polymers via two pathways. A first approach relies upon the synthesis of polyester arms initiated from the alcohol groups of pending sugars distributed along a preformed hydrophilic polymethacrylate backbone obtained by controlled radical polymerization (via ATRP). Various metal-based and organic catalysts/activators have been studied to lead to the desired architectures using this “grafting from” technique. In another synthetic strategy, the lactone polymerization using a carbohydrate initiator has been carried out, followed by end-chain derivatization reactions yielding brush-like copolymers via a “grafting through” technique. Slight modifications of the end-chain functionalities have also afforded the possibility to synthesize amphiphilic mikto-arm copolymers which self-assemble in aqueous medium in micelles characterized by interesting size features affording promising applications as new drug delivery systems. On the other hand this thesis also focuses on the use of carbohydrate moieties in amphiphilic diblock copolymers such as poly(ε-caprolactone)-b-poly(methacrylate-graft-poly(ethylene oxide)-co-6-O-methacryloyl-D-galactopyranose) or poly(ε-caprolactone)-b-poly(methacrylate-graft-poly(ethylene oxide)-co-1-O-methacryloyl-D-mannofuranose), using the combination of lactone ring-opening polymerization with ATRP of the respective functionalized comonomers, followed by selective post-polymerization sugar deprotection. Next to these copolymers based on polylactones and polymethacrylates, fully degradable amphiphilic block copolymers composed of a polycarbonate backbone have been originally designed. To that end, a multi-step procedure involving the synthesis of sugar-substituted cyclic carbonates, block copolymerization reactions and ultimate selective sugar deprotection, has been investigated. The self-organization of the resulting copolymers, e.g., poly(trimethylene carbonate)-b-poly(3-O-(5’-methyl,5’-carboxy-1’,3’-dioxan-2’-one)-D-glucopyranose), has been studied in aqueous medium. Interestingly, the so-formed polymeric micelles proved to display remarkable living cell-targeting properties. Fabian Suriano

Produced water is a major waste produced from oil and natural gas wells in the state of Texas. This water could be a possible source of new fresh water to meet the growing demands of the state after treatment and purification. This thesis describes a research project that evaluated the treatment of brine generated in oil fields (produced water) with ultrafiltration membranes. The characteristics of various ultrafiltration membranes for oil and suspended solids removal from produced water were studied to test whether they could be used in a pretreatment method. The research measured the effect of pressure and flow rate on performance of three commercially available membranes for treatment of oily produced water. Oil and suspended solids removal were measured by using turbidity and oil in water measurements taken periodically. The study also analyzed the flux through the membrane and any effect it had on membrane performance. The research showed that an ultrafiltration membrane provided turbidity removal of over 99% and oil removal of 78% for the produced water samples. The results indicated that the ultrafiltration membranes would be useful as one of the first steps in purifying the water. Membrane cleaning of produced water-fouled membranes by micellar solutions was investigated. A neutral pH and ambient temperature micelle solution for effective cleaning of oily water-fouled membranes was developed and studied. The performance of cleaning solutions on ultrafiltration membranes was investigated on laboratory size membrane testing equipment. Different micro emulsion solutions were studied to evaluate the effect of solution properties on cleaning performance. Three types of multiple membranes were studied, each having the same polyvinylidene fluoride (PVDF) material but with different nominal separation or flux characteristics. The data showed that the use of a micelle solution to clean the produced water-fouled membranes was a feasible and effective method. The study showed with further adjustment of the micelle solution the cleaning effectiveness could be optimized to provide double the effectiveness of current industry methods for membranes fouled by produced water.

Reported in this thesis are the studies of micellar aggregates of four triblock copolymers and the unimolecular micelles of a triblock copolymer. The micelles were prepared from BCF and ACF copolymers. Here A, B, C, and F denote poly(acrylic acid), poly(tert-butyl acrylate), poly(2-cinnamoyloxylethyl methacrylate), and the liquid crystalline poly(perfluorooctylethyl methacrylate) block, respectively. At room temperature (21 oC) in solvents that were selective for the A or B blocks, three of the four copolymers formed exclusively cylindrical micelles regardless of their block ratios. Cylindrical micelles were formed because their geometries best accommodated the mesogen-ordering requirement of the core-forming F block, as supported by the results from wide angle X-ray scattering and differential scanning calorimetric studies. Mesogen-driven cylinder formation was further supported by the observation of ridges formed by collapsed coronal chains on the surfaces of dried cylinders. We also observed a morphological transformation from other micellar morphologies to cylindrical micelles at 70 oC, which is near the isotropic-to-smectic A phase transition temperature for the F blocks. This inter-conversion between the vesicular and cylindrical micelles of an ACF sample could be reversed repeatly by temperature cycling. These results provided additional evidence for the mesogen-driven micellization hypothesis. Unimolecular micelles were prepared from CDC triblock copolymers, where D and C denote poly(dimethylaminoethyl methacrylate) and poly(2-cinnamoyloxylethyl methacrylate), respectively. In selective solvents for the D block at high dilutions, the D chain formed a loop, and the terminal C blocks of the isolated unimer chain associated together as a globule, thus closing the loop and rendering a cyclic structure. Alternatively, the terminal C blocks formed individual globules, thus yielding a pompom-coil-pompom structure. To lock in these structures, the globules were photo-crosslinked. The D block chain was subsequently enlarged for AFM observation through a quaternization step, which increased the chain’s diameter and introduced cations to the chain. The semi-flexible thickened polymer chains and the globules were observed by AFM, confirming unambiguously the hypothesized architectures of the unimolecular micelles. The AFM images also allowed the quantification of the macrocyclic structures, and a correlation between the direct AFM results and determined from a traditional size exclusion chromatography technique. / Thesis (Ph.D, Chemistry) -- Queen's University, 2011-09-26 12:08:28.263

Regensburg, Univ., Diss., 2009.

Zugl.: Köln, Univ., Diss., 2009

Nanomedicine is the fusion between drug therapy and nanotechnology. It is an expanding industry which provides a more efficient and effective way to deliver drugs throughout the body. For individuals suffering from a neurodegenerative disorder, like Huntington’s Disease (HD), current treatments cause major side effects in addition to the disease’s detrimental motor, behavioral and psychiatric symptoms. The goal of the experiment is to encapsulate tetrabenazine, the only FDA approved drug for HD, in a nanoparticle called a micelle. If successful, the new drug nanoparticle can undergo animal testing then clinical trials in hopes of improving patients’ lives.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Au cours de ce travail, nous nous sommes intéressés à la synthèse de composés biologiquement actifs. Dans un premier temps, nous avons étudié la déshydratation des macrocarpals A et B en vue d’obtenir un accès semi-synthétique rapide au macrocarpal G qui possède des propriétés anorexigèniques.Dans un second temps, nous avons développé une nouvelle synthèse énantiosélective du Lévomilnacipran qui est un antidépresseur qui vient de recevoir son autorisation de mise sur le marché aux Etats-Unis et au Canada. Cette synthèse de novo nous a permis d’obtenir le produit actif en neuf étapes avec un rendement global de 32 % et un excès énantiomérique conservé de 88 %. Nous avons ensuite mis au point une synthèse énantiosélective du 1,4-benzodioxane F17807. Cette synthèse en quatre étapes repose sur une étape clé de SNAr du (S)-isopropylidèneglycerol sur un fluorophénol. Cette étape permet d’introduire l’information chirale qui sera maintenue tout au long de la synthèse puisque le produit final est isolé avec un excès énantiomérique de 98 %.Nous avons également synthétisé des analogues du dérivé d’épipodophyllotoxine, F14512. Ces stéréoisomères sont des impuretés qui peuvent apparaitre dans la formulation finale du principe actif. Pour finir, nous avons imaginé de nouvelles formulations nanométriques du composé F14512 afin que celui-ci s’auto-assemble en micelle. Pour cela, quatre amphiphiles ont été synthétisés et les premiers tests montrent une internalisation préférentielle au niveau des tumeurs ou des cellules surexprimant le STP en fonction de leur fonctionnalisation. / This thesis deals with the synthesis of biologically active compounds. In the first chapter, we developed a semi-synthetic process for the exo-dehydration of macrocarpals A and B to get access to macrocarpal G which is a drug known for its anorexigenic activity. The second chapter is dealing with the enantioselective synthesis of the anti-depressive drug Levomilnacipran which has recently been approved by the FDA. This de novo synthesis was performed in 9 steps with an overall yield of 32 % and with an enantiomeric excess of 88 % which was maintained throughout our synthesis. In the third chapter we worked on a novel route for the enantioselective synthesis of the antipsychotic drug F17807. Our four-step synthesis of the 1,4-benzodioxan unit relied, as the key step, on the SNAr reaction of optically active (S)-isopropylidenglycerol on a properly functionalized fluorophenol and subsequent transformations. F17807 was produced with an ee of 98%.The fourth chapter reports our investigations for the synthesis of three stereoisomers of F14512 which is a targeted epipodophyllotoxin-based anticancer drug.Finally, new nanometric formulations of F14512 were designed in the fifth chapter. Four different drug-containing amphiphilic compounds were synthesized, assembled into the corresponding micelles, and evaluated as delivery systems. Preliminary in vitro and in vivo results indicate that the nanomicelles are highly promising for the targeting of tumors as visualized by fluorescence imaging.

Les bactéries photosynthétiques pourpres comme Rhodopseudomonas acidophila (strain 10050) disposent pour collecter la lumière d’un appareil photosynthétique constitué de complexes protéiques membranaires avec des pigments spécialisés. Cet appareil photosynthétique comprend deux types de collecteurs de lumière (light harversting ou LH) appelés LH1 et LH2 et d’un centre réactionnel (CR). La lumière est principalement absorbée par des pigments photosynthétiques liés au complexe LH2 et l'énergie d'excitation résultante est ensuite transférée au complexe LH1 et, de là au centre réactionnel où elle est transformée en énergie chimique. Les données de cristallographie ont permis de montrer que le complexe LH2 se compose d'un ensemble de 9 sous-unités parfaitement symétriques constituées de deux petites sous-unités protéiques α et β associées à 1 caroténoïde (rhodopine glucoside) et 3 bactériochlorophylles-a. Des expériences de spectroscopie de fluorescence en fonction du temps effectuées sur des complexes LH2 uniques ont montré que l'intensité et la position de transition électronique du complexe pouvaient fortement fluctuer avec le temps. Ces observations décrivent un « désordre dynamique » en lien avec la fonction biologique du complexe LH2, qui montre une efficacité d’utilisation de l’énergie lumineuse. Même si un grand nombre d’études met en avant l’existence de ce « désordre » pour interpréter les données expérimentales de fluorescence, peu de travaux ont examiné au niveau moléculaire, les fluctuations locales ou globales au sein du complexe LH2 qui gouvernent ce désordre. La description moléculaire du désordre dynamique du complexe LH2 permettra une compréhension plus précise de ces complexes capables d’utiliser l’énergie solaire avec une grande efficacité, et sont donc d’une grande importance pour la mise en place de systèmes de production d’énergie renouvelable.L’objectif de ce projet de thèse est de mieux comprendre l’origine de ce « désordre » à l’échelle atomique en employant des approches de dynamiques moléculaires classiques. Pour ce faire, nous avons modélisé le complexe LH2 dans différents environnements biomimétiques constitués de détergents (dimethyldodecylamine-N-oxide (LDAO) et le beta octyle glucoside (bOG)) et d'une membrane de POPC. Une première partie de ce travail a consisté à développer des modèles originaux pour ces détergents ainsi que les différents composants du complexe, et à examiner l'agrégation des molécules de détergents autour du complexe. Pour valider nos modèles, des expériences de diffraction des rayons X aux petits angles (SAXS) ont été réalisées avec les complexes LH2-LDAO et LH2-βOG. Dans un second temps, nous avons plus spécifiquement étudié les interactions peptide-pigment,pigment-pigment en fonction de l’environnement. Nos résultats ont montré des différences significatives concernant la dynamique du complexe et les interactions pigment-pigment et pigment-protéine en fonction de l'environnement. Enfin, afin de relier les variations des interactions entre les différents composants du complexe décrits dans nos simulations, aux variations d’absorption du complexe LH2 et au désordre dynamique, des calculs ab-initio ont été réalisés à partir de structures atomiques représentatives de nos simulations. / Purple photosynthetic bacteria, such as Rhodopseudomonas acidophila (strain 10050), have a synthetic apparatus which is composed by membrane protein complexes with specialized pigments to harvest the light. This photosynthetic apparatus is composed of 2 types of light harvesting (LH) complex called LH1 and LH2, and a reactional center (RC). The light is mainly absorbed by photosynthetic pigments bounded to LH2 complex and the resulting excitation energy is transferred to LH1 complex, then to RC where it is transformed to chemical energy. The crystallography data allowed to show that the LH2 complex is composed of a perfectly symmetrical 9 sub-unit ensemble, formed by 2 small protein sub-unit α and β associated to 1 carotenoid (rhodopine glucoside) and 3 bacteriochlorophylls-a. The spectroscopy fluorescence experiences carried out as a function of time on unique LH2 complexes shown that the intensity and the position of the electronic transition of complexes can strongly fluctuate with the time. These observations describe a « dynamic disorder » linked with the biological function of the LH2 complex, which reveal the efficiency of the use of light energy. Even if the large number of studies highlight the existence of this « disorder » to interpret experimental data of fluorescence, a few number of studies analyzed at molecular level the local or global fluctuations inside of LH2 complex which govern this disorder. The molecular description of the dynamic disorder of LH2 complex will permit more precise comprehension about the ability to use of solar energy of these complexes with a huge efficiency, and thus, they are very important for setting up the sustainable energy production system.The aim of this project thesis is a better understanding the origin of this « disorder » at atomic scale by using classical molecular dynamics approaches. In order to do this, we modeled the LH2 complex in different biomimetic environments composed of detergents (dimethyldodecylamine-N-oxide (LDAO) and the β octyle glucoside (βOG)) and of POPC membrane. The first part of this study consisted in developing original models for these detergents, as well as for the different components of the LH2 complex, and to analyze the aggregation of detergent molecules around the complex. To validate our models, small angle X-ray scattering (SAXS) experiments have been realized with the LH2-LDAO and LH2-βOG complexes. In the second part, we specifically studied the interactions of peptide-pigment and pigment-pigment depending on the environment. Our results revealed significant differences concerning the dynamic of the complex and the interactions of pigment-pigment and pigment-protein depending on the environment. In the end, in order to relate the variations of interactions between the different components of complex, as described in our simulations, to the variations of absorption of the LH2 complex and to dynamic disorder, ab-initio calculations have been done from the representative atomic structures of our simulations.

In this article, a multiple-responsive polymer micelles system was constructed by using ionic bond to link the hydrophobic tetraphenylthiophene (TP) fluorophores, which possess the property of aggregation-induced emission enhancement (AIEE), with the hydrophilic poly(N-isopropyl acrylamide) (PNIPAM). The susceptibility of the ionic ammonium-sulfonate (Am-Sul) bonds towards metal ions, acid and base triggered the AIEE-operative fluorescence (FL) response. To exercise the idea, PNIPAM with sulfonate terminal was primarily prepared to react with TP-derivatives functionalized with ammonium groups to generate polymer complex of TP-PNIPAM. When in water, the polymer complex TP-PNIPAM formed micelles with the aggregated TP core interconnecting the hydrophilic PNIPAM shell by the ionic Am-Sul bonds. With the operative AIEE effect, the aggregated TP core of the micelles fluoresced but upon the additions of metal ions, acid and base, the ionic bonds dissociated to result in the collapse of the micelles and the FL quenching. A novel fluorogenic sensor capable to respond to multi-stimuli was therefore constructed. Amphiphilic micelle systems with the hydrophilic poly(N-isopropyl amide) (PNIPAM) shell and the hydrophobic tetraphenylthiophene (TP), which has the novel aggregation-induced emission enhancement (AIEE) feature, core inter-connected by ionic bonds were prepared in this study to explore the AIEE-operative emission response towards critical micelle concentration (CMC) and lower critical solution temperature (LCST). To exercise the idea, TP functionalized ammonium cations and PNIPAM with terminal sulfonate group were individually prepared and mixed together to yield three amphiphilic TP-PNIPAM complexes with different hydrophobic TP to the hydrophilic PNIPAM (x/y) ratios. When in aqueous solution, TP-PNIPAMs form micelles with the aggregated TP core, which emits strongly due to the operative AIEE effect, encompassed by the PNIPAM shell. The resultant CMC and LCST of the TP-PNIPAM micelles can be varied by changing the hydrophobic to the hydrophilic x/y ratio and can be monitored by the AIEE-dominant fluorescence responses towards concentration and temperature variables.