Colloidal suspensions of disk-like particles have been of interest in both colloidal and liquid crystal studies because they exhibit unique liquid crystalline phases different from those of rod-like molecules. Disk-like particles, such as asphaltenes in heavy oil industry, clay particles in agriculture, and red blood cells in biology, are of great interest in a variety of industries and scientific areas. However, to fabricate monodisperse microdisks, uniform in structure or composition with precise control of particle size and shape has not yet succeeded. In this thesis, we show an experimental strategy of using microfluidic technique to fabricate homogeneous α-eicosene microemulsions with chloroform in an aqueous solution of sodium dedecyl sulfate (SDS). The monodisperse chloroform emulsions, generated by the glass-based microfluidic devices, ensure the precise control on microdisk particle size and shape. A systematic investigation was performed to study the relation between the resulted microdisk size and the initial concentration of α-eicosene in chloroform before evaporation. The smectic liquid crystalline phase inside the wax particles controls the coin-like disk shape below the melting temperature of wax’s rotator phase. The kinetics of the disk formation is observed using a polarized light microscope. Dynamic light scattering is used to characterize the Brownian motion of the microdisks, and the rotational diffusion is estimated from the image sequences taken by the charge-coupled device (CCD) camera. Effort has been put into collecting a large quantity of microdisks to investigate the discotic liquid crystalline phases, which can be readily probed by light scattering and microscope. In comparison, X-ray and neutron have to be used for the atomic liquid crystalline phase investigation.

Colloidal suspensions of disk-like particles have been of interest in both colloidal and liquid crystal studies because they exhibit unique liquid crystalline phases different from those of rod-like molecules. Disk-like particles, such as asphaltenes in heavy oil industry, clay particles in agriculture, and red blood cells in biology, are of great interest in a variety of industries and scientific areas. However, to fabricate monodisperse microdisks, uniform in structure or composition with precise control of particle size and shape has not yet succeeded. In this thesis, we show an experimental strategy of using microfluidic technique to fabricate homogeneous α-eicosene microemulsions with chloroform in an aqueous solution of sodium dedecyl sulfate (SDS). The monodisperse chloroform emulsions, generated by the glass-based microfluidic devices, ensure the precise control on microdisk particle size and shape. A systematic investigation was performed to study the relation between the resulted microdisk size and the initial concentration of α-eicosene in chloroform before evaporation. The smectic liquid crystalline phase inside the wax particles controls the coin-like disk shape below the melting temperature of wax’s rotator phase. The kinetics of the disk formation is observed using a polarized light microscope. Dynamic light scattering is used to characterize the Brownian motion of the microdisks, and the rotational diffusion is estimated from the image sequences taken by the charge-coupled device (CCD) camera. Effort has been put into collecting a large quantity of microdisks to investigate the discotic liquid crystalline phases, which can be readily probed by light scattering and microscope. In comparison, X-ray and neutron have to be used for the atomic liquid crystalline phase investigation.

Ce doctorat portait sur le développement de nanoparticules (NPs) photosensibles constituées d’un cœur photolysablepoly(acrylate d'o-nitrobenzyle) (polymère hydrophobe biocompatible - PANB) et d’une couronne basée sur un dérivé du dextrane (polysaccharide bactérien, hydrophile et biodégradable). Dans un premier temps, le PANB-N3 a été synthétisé par i) polymérisation radicalaire contrôlée (SET-LRP) de l’acrylate d’o-nitrobenzyle puis ii) modification chimique de l’extrémité de chaîne par une fonction azoture. En parallèle, le dextrane a été hydrophobisé par quelques chaînes grasses dotées d’un groupe alcyne (obtention du DexAlcyne-15). Ces polymères précurseurs peuvent alors réagir par chimie click CuAAC (Cycloaddition azide-alcyne catalysée par Cu(I)) pour engendrer divers glycopolymères greffés Dex-g-PANB. Dans un deuxième temps, les NPs ont été formulées par deux procédés puis caractérisées en termes de taille, recouvrement en dextrane (quantité par gramme de PANB, épaisseur de la couche surfacique) et stabilité colloïdale en milieu salin, en présence de tensioactif compétitif ou dans un milieu de culture (DMEM). Le procédé de nanoprécipitation a été appliqué aux Dex-g-PANB présentant de fortes fractions massiques en PANB (>40%) alors que le procédé d’émulsion-évaporation de solvant organique a été mis en œuvre en utilisant le DexAlcyne-15 comme tensioactif hydrosoluble et le PANB-N3 comme matériau hydrophobe. Grâce à leurs fonctionnalités complémentaires, une réaction CuAAC peut (ou non) avoir lieu à l’interface liquide/liquide pendant l’élaboration des NPs et conduire à l’obtention de NPs « non clickées » ou « clickées ». Enfin, le caractère photosensible des NPs a été validé par irradiation UV en observant une disparition progressive des NPs résultant de la photolyse des PANB. Afin d’utiliser ces NPs comme systèmes stimulables de délivrance de médicaments, un anticancéreux (Doxorubicine - Dox) a été encapsulé au sein des NPs, pendant leur élaboration. Cette encapsulation a été optimisée et les NPs chargées de DOX ont été caractérisées en termes de taille et d’efficacité d’encapsulation. La libération de la DOX hors des NPs a ensuite été suivie par simple diffusion, ou provoquéepar irradiation UV. Enfin, le potentiel biologique de ces NPs a été évalué vis-à-vis d’une lignée cellulaire tumorale humaine d'origine intestinale isolée d'un adénocarcinome colique (Caco-2). Après vérification de leur biocompatibilité et de la résistance des Caco-2 aux irradiations UV, nous avons pu montrer que les NPs chargées pouvaient libérer suffisamment de DOX en seulement 30 secondes d’irradiation (puissane: 54mW/cm2) pour éradiquer plus de 50% de ces cellules cancéreuses. / This work was focused on the development of light-sensitive nanoparticles (NPs) based on a photodegradable poly(o-nitrobenzyl acrylate) core(PNBA, hydrophobic and biocompatible polymer) and a dextran derivative shell (dextran is a biodegradable and hydrophilic bacterial polysaccharide). Firstly, PNBA-N3 was synthesized by i) Single-Electron Transfer Living Radical Polymerization (SET-LRP) of o-nitrobenzyl acrylate then ii) introduction of one azide end-function. In the same time, DexAlkyne-15 carrying several alkyne groups was produced by hydrophobization of dextran. Such DexAlkyne-15 and PNBA-N3 can react by CuAAC (Cu(I)-catalyzed azide-alkyne cycloaddition) click chemistry leading to Dex-g-PNBA glycopolymers with various macromolecular parameters. Secondly, NPs were produced by comparing two processes then characterized in terms of size, dextran amount, shell thickness and colloidal stability in NaCl or cell culture media, or in presence of one strong surfactant. On one hand, NPs were made by nanoprecipitation of Dex-g-PNBA exhibiting high PNBA weight fractions (>40 %). On the other hand, NPs were produced by emulsion-evaporation of the organic solvent using DexAlkyne-15 as water-soluble surfactant and PNBA-N3 as hydrophobic materials. In this case, in situ CuAAC occurred (or not) at the liquid/liquid interface during the NPs formulation, leading to “clicked” and “not-clicked” NPs. Finally, NPs disruption was studied by UV irradiation according the PNBA chains photolysis. To use such NPs as smart drug delivery systems, Doxorubicin (DOX - an anticancer agent), was loaded inside the NPs during their elaboration. The experimental conditions were optimized to enhance the DOX encapsulation. The kinetics release of encapsulated DOX were studied by diffusion or under UV irradiation. Finally, the biological potential of these NPs was estimated towards Caco-2 (continuous line of heterogeneous human epithelial colorectal adenocarcinoma cells). After checking the NPs biocompatibility and theCaco-2 strength under UV irradiation, we proved that such loaded NPs can release enough DOX under 30 second irradiation (power: 54mW/cm2) to decrease the Caco-2 viability about more than 50%.