Dans le domaine du transport, le zingage (pour lutter contre la corrosion), la passivation (pourrenforcer le pouvoir anticorrosion et améliorer l’esthétique) et la finition (pour la lubrification) sont lestrois traitements appliqués sur les petites pièces mécaniques telles que les vis. L’objectif principal decette étude est d’apporter la propriété lubrifiante à la couche de passivation, permettant ainsi de réduirele nombre d’étape et de réaliser des économies considérables. Pour atteindre cet objectif, deuxstratégies ont été adoptées : la fonctionnalisation de particules de silice par un silane fluoré etl’encapsulation d’un lubrifiant par de la silice.Des particules de silice, sphériques et monodisperses de taille contrôlée (de 40 à 100 nm), ontété fonctionnalisées par un silane fluoré, en une seule étape de synthèse à partir d’une microémulsion.Ces particules améliorent les propriétés lubrifiantes de la couche de finition mais pas celles de lapassivation.Une simple émulsion en milieu acide a permis de synthétiser des microcapsules contenant unlubrifiant (le PAO, polyalphaoléfine ou le n-octadécane à changement de phase à 27°C), de taillemoyenne de quelques micromètres. Le taux maximal d’encapsulation de lubrifiant est environ de 70%,ces capsules n’ont pas apporté les propriétés lubrifiantes à la couche de passivation sur des vis, le tauxd’incorporation des capsules dans cette couche étant trop faible / In the field of transport, zinc coating (to combat corrosion), passivation coating (to increasecorrosion protection and be more aesthetic) and topcoat (for lubrication) are three treatments appliedto small mechanical parts such as screws. The main aim of this study is to provide lubricatingproperties to the passivated layer to reduce the number of steps in the coating process and substantiallyreduce costs. The method includes: silica functionalized with a fluorinated silane and a lubricantencapsulated in silica.Spherical and monodispersed silica particles (between 40 to 100nm) were functionalized witha fluorinated silane using a one-step synthesis from the initial microemulsion. This resulted in theparticles enhancing the lubricating properties of the topcoat but not those of the passivation coating.Microcapsules containing a lubricant (PAO, polyalphaolefin or n-octadecane with a phasechange at 27°C) with an average size of a few micrometers were synthetized in a simple emulsionunder acidic conditions. The maximum encapsulation rate of the lubricant was 70%. These capsulesdid not provide lubricating properties to the passivated coating on the screws. This is because the rateof incorporation of the capsules in this layer is too weak.

Le papier bioactif est obtenu par la modification de substrat du papier avec des biomolécules et des réactifs. Ce type de papier est utilisé dans le développement de nouveaux biocapteurs qui sont portables, jetables et économiques visant à capturer, détecter et dans certains cas, désactiver les agents pathogènes. Généralement les papiers bioactifs sont fabriqués par l’incorporation de biomolécules telles que les enzymes et les anticorps sur la surface du papier. L’immobilisation de ces biomolécules sur les surfaces solides est largement utilisée pour différentes applications de diagnostic comme dans immunocapteurs et immunoessais mais en raison de la nature sensible des enzymes, leur intégration au papier à grande échelle a rencontré plusieurs difficultés surtout dans les conditions industrielles. Pendant ce temps, les microcapsules sont une plate-forme intéressante pour l’immobilisation des enzymes et aussi assez efficace pour permettre à la fonctionnalisation du papier à grande échelle car le papier peut être facilement recouvert avec une couche de telles microcapsules. Dans cette étude, nous avons développé une plate-forme générique utilisant des microcapsules à base d’alginate qui peuvent être appliquées aux procédés usuels de production de papier bioactif et antibactérien avec la capacité de capturer des pathogènes à sa surface et de les désactiver grâce à la production d’un réactif anti-pathogène. La conception de cette plate-forme antibactérienne est basée sur la production constante de peroxyde d’hydrogène en tant qu’agent antibactérien à l’intérieur des microcapsules d’alginate. Cette production de peroxyde d’hydrogène est obtenue par oxydation du glucose catalysée par la glucose oxydase encapsulée à l’intérieur des billes d’alginate. Les différentes étapes de cette étude comprennent le piégeage de la glucose oxydase à l’intérieur des microcapsules d’alginate, l’activation et le renforcement de la surface des microcapsules par ajout d’une couche supplémentaire de chitosan, la vérification de la possibilité d’immobilisation des anticorps (immunoglobulines G humaine comme une modèle d’anticorps) sur la surface des microcapsules et enfin, l’évaluation des propriétés antibactériennes de cette plate-forme vis-à-vis l’Escherichia coli K-12 (E. coli K-12) en tant qu’un représentant des agents pathogènes. Après avoir effectué chaque étape, certaines mesures et observations ont été faites en utilisant diverses méthodes et techniques analytiques telles que la méthode de Bradford pour dosage des protéines, l’électroanalyse d’oxygène, la microscopie optique et confocale à balayage laser (CLSM), la spectrométrie de masse avec désorption laser assistée par matrice- temps de vol (MALDI-TOF-MS), etc. Les essais appropriés ont été effectués pour valider la réussite de modification des microcapsules et pour confirmer à ce fait que la glucose oxydase est toujours active après chaque étape de modification. L’activité enzymatique spécifique de la glucose oxydase après l’encapsulation a été évaluée à 120±30 U/g. Aussi, des efforts ont été faits pour immobiliser la glucose oxydase sur des nanoparticules d’or avec deux tailles différentes de diamètre (10,9 nm et 50 nm) afin d’améliorer l’activité enzymatique et augmenter l’efficacité d’encapsulation. Les résultats obtenus lors de cette étude démontrent les modifications réussies sur les microcapsules d’alginate et aussi une réponse favorable de cette plate-forme antibactérienne concernant la désactivation de E. coli K-12. La concentration efficace de l’activité enzymatique afin de désactivation de cet agent pathogénique modèle a été déterminée à 1.3×10-2 U/ml pour une concentration de 6.7×108 cellules/ml de bactéries. D’autres études sont nécessaires pour évaluer l’efficacité de l’anticorps immobilisé dans la désactivation des agents pathogènes et également intégrer la plate-forme sur le papier et valider l’efficacité du système une fois qu’il est déposé sur papier. / Bioactive paper is obtained through the modification of paper substrate with biomolecules and reagents. It is used in the development of novel biosensors that are portable, disposable and inexpensive, aimed at capturing, detecting and in some cases deactivating pathogens. Generally bioactive papers are made by incorporating biomolecules such as enzymes and/or antibodies on to paper. The immobilization of such biomolecules on solid surfaces is widely used for different diagnostic applications such as in immunosensors and immunoassays but due to the sensitive nature of enzymes, their large scale incorporation into paper has faced several difficulties especially under industrial papermaking conditions. The functionalization of paper at large scale is possible because paper can be easily coated with a layer of microcapsules, which have proven to be an efficient immobilization platform for enzymes and to allow. In this study, we developed a generic alginate-based platform incorporating microcapsules that can be applied to current paper production processes to prepare antibacterial bioactive paper with the ability to capture pathogens on its surface and to deactivate them by producing an anti-pathogenic agent. The design of the antibacterial platform is based on constant production of hydrogen peroxide as the antibacterial agent inside the alginate microcapsules. Hydrogen peroxide production is achieved through oxidation of glucose, catalyzed by the enzyme glucose oxidase encapsulated inside the alginate beads. The different steps of development included the entrapment of glucose oxidase inside alginate microcapsules, the reinforcement and surface activation of microcapsules by adding an additional layer of chitosan, investigating the possibility of immobilization of antibodies (human immunoglobulin G as a model antibody) on the surface of microcapsules and, finally, verifying the antibacterial properties of the system against Escherichia coli K-12 (E. coli K-12) as a representative pathogen. During development, certain measurements and observations were made using various analytical methods and techniques such as Bradford protein assay, oxygen electroanalysis, optical and confocal laser canning microscopy (CLSM), matrix assisted laser desorption/ionization- time of flight mass spectrometry (MALDI-TOF-MS), etc. Appropriate tests were performed to validate the successful modification of microcapsules and to ensure that glucose oxidase is still active after each modification. It was found that the encapsulated glucose oxidase maintained the specific enzymatic activity of 120±30 U/g. Subsequent efforts were made to immobilize glucose oxidase on gold NPs of two different diameters (10.9 nm and 50 nm) to enhance the enzymatic activity and increase the encapsulation efficiency. The results obtained during this study demonstrate successful modifications on alginate microcapsules and also a successful response of such antibacterial platform regarding deactivation of the pathogen representative, E. coli K-12. The threshold for the enzymatic activity was found to be 1.3×10-2 U/ml for E. coli K-12 growth inhibition of 6.7×108 cells/ml. Further studies are needed to assess the efficiency of immobilized antibody in the capture of pathogens and also to incorporate the platform onto paper and to validate the efficiency of the system once it is coated on paper.

Les mégacaryocytes sont des cellules de la moelle osseuse, à l’origine de la production des plaquettes sanguines. Quand elles arrivent à maturité, elles grossissent et émettent des prolongements de cytoplasme à travers la paroi des vaisseaux irriguant la moelle. Dans la circulation sanguine, ces prolongements, soumis aux forces de l’écoulement, s’allongent et se rompent pour former des plaquettes. Des techniques microfluidiques capables de produire des plaquettes in vitro existent et sont une alternative prometteuse au don. Mais le rendement reste à améliorer. Pour cela, il est nécessaire de mieux comprendre la fragmentation des mégacaryocytes en plaquettes. Ce travail de doctorat s’inscrit dans ce contexte et sera développé en deux axes principaux dans ce manuscrit. Dans une première partie nous développons une méthode pour trier des cellules en fonction de leur déformabilité, afin de savoir si les propriétés mécaniques d’un mégacaryocyte sont liées à leur stade de maturité. La méthode a d’abord été mise au point avec des microcapsules. Leurs propriétés mécaniques sont déterminées par analyse inverse à partir de la mesure de leur forme en écoulement dans des constrictions droites. Puis le dispositif utilisé a été miniaturisé pour s’adapter à la taille des cellules. Pour la caractérisation de leurs propriétés mécaniques, deux outils ont été utilisés: l’analyse inverse et la microscopie à force atomique sans pointe. Une deuxième partie porte sur l’étude de l’élongation et de la rupture de mégacaryocytes soumis écoulement. Nous avons quantifié les variations spatiotemporelles du taux d’élongation et développé un protocole d’ablation laser pour étudier les mécanismes de rupture de cellules en élongation. / When they mature in the bone marrow, the precursors of platelets, called megakaryocytes, grow and extend protrusions able to join blood circulation. There these protrusions elongate and break into platelets. Microfluidic techniques for in vitro platelet production represent a promising alternative to donation. In order to enhance platelet production and match the needs of clinical applications such as transfusion, we need to better understand the fragmentation of megakaryocytes into platelets. Our contribution will be described in this manuscript in two main axes. First, in order to know if mechanical properties of megakaryocytes can indicate their maturity stage, we develop a cell sorting method based on deformability. The method is first validated with microcapsules. Their mechanical properties are determined by inverse analysis from their shape under flow in straight microchannels. Then the device is downscaled. The characterization of cell mechanical properties are performed using inverse analysis and tipless atomic force microscopy. Second, we study megakaryocyte elongation and rupture in a microfluidic device. We quantify the spatial and temporal variations of the elongation rate and develop a laser ablation protocol to trigger and study the rupture of elongating cells.

This work focused on the design of functional capsules made of chemically modified polysaccharides. The layer-by-layer capsules have attracted great interest due to their Indeed, as an advanced multifunctionality which can be advantageously used for pharmaceutical and biomedical applications. Polysaccharides, which are generally biocompatible and biodegradable, are very attractive materials for the construction of bio-related multilayer systems. Considering the intrinsic antibacterial properties of chitosan (CHI), this polysaccharide was selected and quaternized to prepare in physiological conditions contact-killing capsules by combination with hyaluronic acid (HA). The relationship between the antibacterial activity of the quaternized chitosan derivatives (QCHI) and that of QCHI-based capsules was investigated. Then, in order to encapsulate small hydrophobic drugs within the wall of capsules, alkylated derivatives of HA were used as the negatively charged partner of QCHI for the capsules formation. The encapsulation of the hydrophobic dye, nile red (NR), in the hydrophobic shell of capsules was determined. At last, to release the payload under mild conditions was studied by synthesizing rapidly degradable capsules composed of hydrolysable cationic dextran derivatives and HA. The degradation of the layer-by-layer assemblies, both multilayer films and microcapsules is discussed. / Ce travail de thèse porte sur la conception de capsules fonctionnelles à base de polysaccharides chimiquement modifiés. Les capsules couche par couche connaissent actuellement un essor important lié à leur multifonctionnalité pouvant être avantageusement mise à profit dans les domaines pharmaceutique et biomédical. Les polysaccharides, généralement biocompatibles et biodégradables, constituent des matériaux de choix pour la construction de systèmes multicouches. Compte tenu des propriétés antibactériennes intrinsèques du chitosane (CHI), ce polysaccharide a été choisi puis quaternisé afin de préparer dans des conditions physiologiques des capsules par complexation avec l'acide hyaluronique (HA), capables de tuer les bactéries par simple contact. La relation entre l'activité antibactérienne des dérivés quaternisés du chitosane (QCHI) et celle des capsules préparées à partir de QCHI a été étudiée. En outre, afin d'encapsuler des médicaments hydrophobes dans la paroi des capsules, des dérivés alkylés du HA ont été utilisés en tant que partenaire chargé négativement du QCHI pour la formation des capsules. L'encapsulation d'une sonde fluorescente hydrophobe, le nile rouge (NR), dans le réservoir hydrophobe des capsules a été réalisée avec succès. Enfin, pour libérer des médicaments encapsulés dans des capsules dans des conditions douces, des capsules rapidement dégradables comprenant des dérivés cationiques hydrolysables du dextrane et de HA ont été préparées. La dégradation des assemblages couches par multicouches a été analysée par différentes approches à la fois à partir de capsules et de films plans.

L’objectif de cette thèse est d’étudier expérimentalement les deformations de microcapsules dans un écoulement confiné. Les microcapsules sont composées d’albumine du sérum humain avec des concentrations de 5 à 20 [g/100mL]. Leur taille varie de 50 à 1000 [μm]. Les capsules sont injectées dans des écoulements de Poiseuille produits dans des canaux microfluidiques présentant deux sections différentes : circulaire ou carrée.La mesure des caractéristiques géométriques de microcapsules déformées couplée à des simulations numériques mène à la détermination du module de cisaillement surfacique. Cette caractéristique mécanique augmente fortement tant avec la taille qu’avec la concentration en protéine de la capsule, et plus précisément avec le produit de ces deux paramètres.Le fluide est ensemencé avec des microparticules pour mesurer l’écoulement induit par une capsule dans un capillaire cylindrique par la méthode de la vélocimétrie par suivi de particules. Les zones de recirculation et de perturbation sont alors déduites et comparées avec la simulation numérique d’un objet rigide dans un capillaire et présentant le profil donné par les expériences. Finalement un système original de visualisation optique est consacré à l’observation simultanée de la vue de côté et de la vue de face des capsules pour obtenir sa forme entière. Ceux-ci révèlent l’existence des plis tout autour de la membrane des capsules. Le seuil de formation et l’évolution de ces plis sont étudiés en fonction de la vitesse, de la taille et du confinement, dans des canaux de section circulaire ou carrée. / The objective of this thesis is to study experimentally microcapsule deformations in confined flows. The microcapsules are made of cross-linked proteins, the human serum albumin (HSA) with concentrations from 5 to 20 [g/100mL]. Their size vary from 50 to 1000 [μm]. Capsules are injected in Poiseuille flows generated within microfluidics channels with two different cross sections geometries : circular or square.The measurement of geometrical characteristics of deformed microcapsules coupled with numerical simulations leads to the determination of the surface shear modulus. This mechanical characteristic increases strongly with both the size and the protein concentration of the capsule, and more precisely with the product of these two parameters.The flow is seeded with microparticles to measure the induced flow of a capsule in a cylindrical capillary by particle tracking velocimetry. The recirculation and perturbation zones are then deduced and compared with numerical simulation of a rigid body flowing in a capillary. Finally an original system of optical visualization is dedicated to the simultaneous observation of the side and the front view of the capsules to get its whole shape. These reveal radial wrinkles all around capsules membrane. The formation threshold and the evolution of these wrinkles are studied as function of the capsule velocity and size and the confinement within capillaries with circular or square cross–section.

L'utilisation des microcapsules fabriquées à partir de matériaux respectueux de l'environnement pour des applications textiles médicales a été étudiée et développée fortement au cours des dernières années. Le but de cette thèse est d'élaborer les textiles anti-inflammatoires à base de microcapsules respectueuses de l'environnement, utilisant trois types de matériaux textiles (coton, peco 65/35 et polyester) et cinq niveaux de longueur de boucle (2.81, 2.83, 2.87, 2,96 et 3,05 mm) sur étoffes tricotées à verrouillage de coton (nombre de fils Ne40). Les influences de la concentration en saponine, de la vitesse d'agitation au cours de l'étape d'émulsification et du volume d'éthyle acétate ajouté à la phase aqueuse sur les caractéristiques des microcapsules ont été étudiées. L'étude a également étudié les effets du rapport massique du coton et de la longueur de boucle des étoffes tricotées sur la distribution des microcapsules, la capacité de chargement des microcapsules et la capacité de libération de l'ibuprofène des étoffes tricotées traités par microcapsules. Les microcapsules d'Eudragit RSPO contenant de l'ibuprofène ont été élaborées par la technique d'évaporation de solvant, en utilisant le tensioactif bio-sourcé quillaja saponine et le solvant non halogéné d'éthyle acétate. Les microcapsules obtenues présentaient les formes sphériques avec un diamètre d (0,5) de 21,5 μm, approprié pour les applications textiles. Il a été trouvé que, pour empêcher la déformation des microcapsules pendant la traitement du textile, la séchage doit être effectuée sous vide à 45 ° C. Lorsque le rapport de teneur en fibres de coton dans le tissu augmentait, la distribution des microcapsules était moins régulière, ce qui entraînait un taux de libération plus faible de l'ibuprofène à partir des étoffes tricotées traités aux microcapsules. En outre, lorsque la longueur de la boucle augmente, la capacité de chargement des microcapsules des étoffes tricotées traités augmente, la distribution des microcapsules sur le tissu devient moins régulière et la vitesse de libération de l'ibuprofène des tissus traités aux microcapsules diminue. De plus, l'augmentation de l'extension du étoffes tricotées a favorisé la libération d'ibuprofène à partir des étoffes tricotées traités par les microcapsules à travers la peau de porc / The use of the microcapsules made from eco-friendly materials for medical textile applications has been researched and developed strongly in recent years. The aim of this thesis is to elaborate the anti-inflammatory textiles basing on eco-friendly microcapsules,using three kinds of textile materials (cotton, peco 65/35 and polyester)and five levels of the loop length (2.81, 2.83, 2.87, 2.96 and 3.05 mm) on the cotton interlock knitted fabrics (yarn count Ne40). The influences of the saponin concentration, the stirring rate during the emulsification step and the volume of ethyl acetate added to the aqueous phase on the characteristics of the microcapsules were studied. The influence of condition in drying on microcapsule’s morphology was also investigated.The thesis also researched the effects of cotton mass ratio and loop length of fabric on the microcapsule distribution, the microcapsule loading capability and the release capability of ibuprofen from the microcapsule treated fabrics. The Eudragit RSPO microcapsules containing ibuprofen were successfully elaborated by solvent evaporation technique, using the bio-sourced surfactant quillajasaponin and the non-halogenated solvent ethyl acetate. The obtained microcapsules exhibited the spherical shapes with d(0.5) diameter of 21.5 m, suitable for the textile applications. It was found that in order to keep the microcapsules from deformation during the textile finishing, the drying stage should be carried out in vacuum at 45oC. When the content ratio of cotton fibers in the fabric increased,the microcapsule distribution was less even, resulting in the lower release rate of ibuprofen from the microcapsule-treated fabrics. Besides, when the loop length increased, the microcapsule loading capability of the treated fabrics increased, the microcapsule distribution on the fabric became less even and the release rate of ibuprofen from the microcapsule-treated fabrics decreased. Furthermore, increasing the fabric extension favored the release of ibuprofen from the microcapsule-treated fabrics through the pigskin

Un papier bioactif est obtenu par la modification d’un papier en y immobilisant une ou plusieurs biomolécules. La recherche et le développement de papiers bioactifs est en plein essor car le papier est un substrat peu dispendieux qui est déjà d’usage très répandu à travers le monde. Bien que les papiers bioactifs n’aient pas connus de succès commercial depuis la mise en marche de bandelettes mesurant le taux de glucose dans les années cinquante, de nombreux groupes de recherche travaillent à immobiliser des biomolécules sur le papier pour obtenir un papier bioactif qui est abordable et possède une bonne durée de vie. Contrairement à la glucose oxidase, l’enzyme utilisée sur ces bandelettes, la majorité des biomolécules sont très fragiles et perdent leur activité très rapidement lorsqu’immobilisées sur des papiers. Le développement de nouveaux papiers bioactifs pouvant détecter des substances d’intérêt ou même désactiver des pathogènes dépend donc de découverte de nouvelles techniques d’immobilisation des biomolécules permettant de maintenir leur activité tout en étant applicable dans la chaîne de production actuelle des papiers fins. Le but de cette thèse est de développer une technique d’immobilisation efficace et versatile, permettant de protéger l’activité de biomolécules incorporées sur des papiers. La microencapsulation a été choisie comme technique d’immobilisation car elle permet d’enfermer de grandes quantités de biomolécules à l’intérieur d’une sphère poreuse permettant leur protection. Pour cette étude, le polymère poly(éthylènediimine) a été choisi afin de générer la paroi des microcapsules. Les enzymes laccase et glucose oxidase, dont les propriétés sont bien établies, seront utilisées comme biomolécules test. Dans un premier temps, deux procédures d’encapsulation ont été développées puis étudiées. La méthode par émulsion produit des microcapsules de plus petits diamètres que la méthode par encapsulation utilisant un encapsulateur, bien que cette dernière offre une meilleure efficacité d’encapsulation. Par la suite, l’effet de la procédure d’encapsulation sur l’activité enzymatique et la stabilité thermique des enzymes a été étudié à cause de l’importance du maintien de l’activité sur le développement d’une plateforme d’immobilisation. L’effet de la nature du polymère utilisé pour la fabrication des capsules sur la conformation de l’enzyme a été étudié pour la première fois. Finalement, l’applicabilité des microcapsules de poly(éthylèneimine) dans la confection de papiers bioactifs a été démontré par le biais de trois prototypes. Un papier réagissant au glucose a été obtenu en immobilisant des microcapsules contenant l’enzyme glucose oxidase. Un papier sensible à l’enzyme neuraminidase pour la détection de la vaginose bactérienne avec une plus grande stabilité durant l’entreposage a été fait en encapsulant les réactifs colorimétriques dans des capsules de poly(éthylèneimine). L’utilisation de microcapsules pour l’immobilisation d’anticorps a également été étudiée. Les avancées au niveau de la plateforme d’immobilisation de biomolécules par microencapsulation qui ont été réalisées lors de cette thèse permettront de mieux comprendre l’effet des réactifs impliqués dans la procédure de microencapsulation sur la stabilité, l’activité et la conformation des biomolécules. Les résultats obtenus démontrent que la plateforme d’immobilisation développée peut être appliquée pour la confection de nouveaux papiers bioactifs. / Biosensing paper attracts increasing attention due to its benefits of being simple, visible, portable and useful for detecting various contaminants, pathogens and toxins. While there has been no bioactive paper commercialized since glucose paper strips developed in the fifties, many research groups are working to immobilize biomolecules on paper to achieve a bioactive paper that is affordable and has good shelf life. The goal of this research is to develop some highly useful bioactive paper that could, for example, measure blood glucose, or immediately detect and simultaneously deactivate pathogens such as neuraminidase and E.coli. Previously, bioactive paper was produced either through physically absorbing biorecognition elements or printing bio-ink onto paper substrate. Our methodology for fabrication of bioactive paper strips is compatible with existing paper making process and includes three procedures: the fabrication of microcapsules, enzyme or antibody microencapsulation, immobilization of enzymes or antibody-entrapped microcapsules into paper pulp. The first step, in fabricating of bioactive paper strips is to produce biocompatible and inexpensive microcapsules with suitable parameters. To do so, two types of microencapsulation methods were compared; the emulsion method and the vibration nozzle method accomplished with an encapsulator. The parameters for producing optimal microcapsules with both methods were studied. Factors that affect their diameter, wall thickness, shell pore size, encapsulation efficiency and membrane compositions were also discussed. By comparison, microcapsules prepared with poly(ethyleneimine) (PEI) by the emulsion method exhibit properties that were more suitable for enzyme encapsulation and paper making process, whereas the microcapsules prepared by the vibration nozzle method were too big to be immobilized within paper pulp, and had lower encapsulation efficiency, enzymatic activity and productivity. Thus the emulsion method was chosen for subsequent experiments such as enzyme and antibody microencapsulation and bacterial vaginosis (BV) paper preparation. Microcapsules made by the emulsion method were semi-permeable in that the diffusion of substrate and product molecules were allowed freely across the membranes but the encapsulated enzymes would be retained inside. Glucose oxidase from Aspergillus niger (GOx) and laccase from Trametes versicolor (TvL) microcapsules showed high encapsulation efficiency, but the encapsulation process caused a severe decrease in the specific activities of both enzymes. Results from circular dichroism (CD) studies, fluorescence properties, enzymatic activities of free enzymes and Michaelis-Menten behavior demonstrated that the Vmax decrease for GOx was due to the restriction of diffusion across microcapsule membranes with pore size less than 5 nm. The microencapsulation process improved the thermal stability of GOx but decreased that of laccase. Bioactive papers were fabricated either by incorporating microcapsules containing different enzymes or empty microcapsules soaked in substrate and enhancer solution into the paper pulp during the sheet making process. Both the GOx and the BV paper strips underwent a color change in the presence of glucose and potassium iodide, and sialidase from Clostridium perfringens respectively. Some preliminary studies on antibody sensitized microcapsules, in which antibody was either encapsulated within the PEI microcapsules or conjugated to its membranes, were also performed. Our objective was to establish an enzyme immobilization platform based on microencapsulation techniques for paper based biosensors. Even though our current studies only focused on the microencapsulation of two enzymes, TvL and GOx, as well as the bioactive paper preparation, a similar approach can be applied to other enzymes. We believe that this immobilization method can potentially be employed for bioactive paper preparation on an industrial scale.

A corrosão nos materiais metálicos causa sérias perdas financeiras e impactos ambientais. Apesar de eficientes, os revestimentos orgânicos podem gerar fissuras com o tempo, propiciando locais favoráveis à corrosão. Diante disso, o conceito de autorreparação em revestimentos tem sido estudado, para que este tipo de dano seja minimizado, sem necessitar da intervenção humana. O método de encapsulamento de formadores de filme em microcápsulas poliméricas é bastante utilizado nos sistemas de autorregeneração. Neste trabalho, estudou-se o processo de emulsificação do óleo de linhaça, etapa determinante para a obtenção das microcápsulas, que serão posteriormente aditivadas em um primer de epóxi base água. Inicialmente, foi necessário aperfeiçoar o preparo da emulsão, analisando-se para isso três tipos diferentes de tensoativos em termos de propriedades e composições. Foi feito um planejamento estatístico no qual se adotou o modelo de projeto fatorial completo para cada um dos tensoativos, onde os fatores analisados foram a variação da fração mássica do tensoativo, a aplicabilidade do ultrassom ou dispersor Ultra-Turrax® e a adição ou não de cloreto de sódio. O pequeno número de ensaios envolvidos e a simplicidade para se analisar e interpretar os dados justificam a escolha deste modelo. As variáveis resposta foram a determinação do diâmetro médio volumétrico das gotículas e a medida do potencial zeta das emulsões para analisar a estabilidade das mesmas. Além disso, observou-se a forma, tamanho e característica das gotículas com o auxílio de um microscópio óptico. A estabilidade da emulsão também foi avaliada pela observação e registro fotográfico da separação de fases, depois de certo tempo em repouso, em um tubo de ensaio. Após a determinação do melhor tensoativo e condições de preparo da emulsão na obtenção das microcápsulas, estas foram obtidas e adicionadas no primer e o mesmo foi aplicado sobre corpos de prova de aço carbono. O efeito de autorreparação proporcionado pela ruptura das microcápsulas ao se provocar um defeito foi avaliado pelas técnicas de espectroscopia de impedância eletroquímica (EIS), técnica de varredura com eletrodo vibratório (SVET) e pelo ensaio acelerado de corrosão em câmara de névoa salina (SSC). As microcápsulas foram caracterizadas por microscopia óptica e microscopia eletrônica de varredura (SEM). / The corrosion of metallic materials causes serious financial losses and environmental impacts. Although efficient, organic coatings may generate cracks over time, generating potential sites for corrosion. Hence, the self-healing concept on coatings has been studied in order to minimize this type of damage, without requiring human intervention. The encapsulation method of film formers in polymeric microcapsules is widely used in self-healing systems. In this study, the emulsification process of linseed oil was investigated, since it is a determining step to obtain the microcapsules that will later be doped in a water based epoxy primer. Initially, it was necessary to improve the emulsion preparation, by analyzing three types of surfactants with different properties and compositions. A statistical planning adopting the full factorial design model was conducted for each of the surfactants, in which the factors considered were the variation of the weight fraction of surfactant, and the use or not of ultrasound, Ultra-Turrax® disperser and sodium chloride. The small number of trials involved and the simplicity to analyze and interpret the data justify the choice of this statistical model. The response variables were the determination of the droplet volumetric mean diameter and the measurement of the zeta potential of the emulsions to assess its stability. Moreover, the shape and characteristics of the droplets were observed with the aid of an optical microscope. The emulsion stability was also evaluated by observation and photographic register of phase separation after some rest time in a test tube. After determining the best surfactant and conditions for the emulsification to obtain the microcapsules, they were produced and added to the primer, which was applied on carbon steel specimens. The self-healing effect provided by the rupture of the microcapsules after an intentional defect was evaluated by electrochemical impedance spectroscopy (EIS), scanning vibrating electrode technique (SVET) and accelerated corrosion tests in a salt spray chamber (SSC). The microcapsules were characterized by optical and scanning electron microscopes (SEM).

A corrosão nos materiais metálicos causa sérias perdas financeiras e impactos ambientais. Apesar de eficientes, os revestimentos orgânicos podem gerar fissuras com o tempo, propiciando locais favoráveis à corrosão. Diante disso, o conceito de autorreparação em revestimentos tem sido estudado, para que este tipo de dano seja minimizado, sem necessitar da intervenção humana. O método de encapsulamento de formadores de filme em microcápsulas poliméricas é bastante utilizado nos sistemas de autorregeneração. Neste trabalho, estudou-se o processo de emulsificação do óleo de linhaça, etapa determinante para a obtenção das microcápsulas, que serão posteriormente aditivadas em um primer de epóxi base água. Inicialmente, foi necessário aperfeiçoar o preparo da emulsão, analisando-se para isso três tipos diferentes de tensoativos em termos de propriedades e composições. Foi feito um planejamento estatístico no qual se adotou o modelo de projeto fatorial completo para cada um dos tensoativos, onde os fatores analisados foram a variação da fração mássica do tensoativo, a aplicabilidade do ultrassom ou dispersor Ultra-Turrax® e a adição ou não de cloreto de sódio. O pequeno número de ensaios envolvidos e a simplicidade para se analisar e interpretar os dados justificam a escolha deste modelo. As variáveis resposta foram a determinação do diâmetro médio volumétrico das gotículas e a medida do potencial zeta das emulsões para analisar a estabilidade das mesmas. Além disso, observou-se a forma, tamanho e característica das gotículas com o auxílio de um microscópio óptico. A estabilidade da emulsão também foi avaliada pela observação e registro fotográfico da separação de fases, depois de certo tempo em repouso, em um tubo de ensaio. Após a determinação do melhor tensoativo e condições de preparo da emulsão na obtenção das microcápsulas, estas foram obtidas e adicionadas no primer e o mesmo foi aplicado sobre corpos de prova de aço carbono. O efeito de autorreparação proporcionado pela ruptura das microcápsulas ao se provocar um defeito foi avaliado pelas técnicas de espectroscopia de impedância eletroquímica (EIS), técnica de varredura com eletrodo vibratório (SVET) e pelo ensaio acelerado de corrosão em câmara de névoa salina (SSC). As microcápsulas foram caracterizadas por microscopia óptica e microscopia eletrônica de varredura (SEM). / The corrosion of metallic materials causes serious financial losses and environmental impacts. Although efficient, organic coatings may generate cracks over time, generating potential sites for corrosion. Hence, the self-healing concept on coatings has been studied in order to minimize this type of damage, without requiring human intervention. The encapsulation method of film formers in polymeric microcapsules is widely used in self-healing systems. In this study, the emulsification process of linseed oil was investigated, since it is a determining step to obtain the microcapsules that will later be doped in a water based epoxy primer. Initially, it was necessary to improve the emulsion preparation, by analyzing three types of surfactants with different properties and compositions. A statistical planning adopting the full factorial design model was conducted for each of the surfactants, in which the factors considered were the variation of the weight fraction of surfactant, and the use or not of ultrasound, Ultra-Turrax® disperser and sodium chloride. The small number of trials involved and the simplicity to analyze and interpret the data justify the choice of this statistical model. The response variables were the determination of the droplet volumetric mean diameter and the measurement of the zeta potential of the emulsions to assess its stability. Moreover, the shape and characteristics of the droplets were observed with the aid of an optical microscope. The emulsion stability was also evaluated by observation and photographic register of phase separation after some rest time in a test tube. After determining the best surfactant and conditions for the emulsification to obtain the microcapsules, they were produced and added to the primer, which was applied on carbon steel specimens. The self-healing effect provided by the rupture of the microcapsules after an intentional defect was evaluated by electrochemical impedance spectroscopy (EIS), scanning vibrating electrode technique (SVET) and accelerated corrosion tests in a salt spray chamber (SSC). The microcapsules were characterized by optical and scanning electron microscopes (SEM).

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2014-09-24T14:14:57Z No. of bitstreams: 2 Reis, Pamela Cristina de Sousa Guardiano.pdf: 1296512 bytes, checksum: 257e678ee16ea253856f4f88bba00934 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Cláudia Bueno (claudiamoura18@gmail.com) on 2014-09-25T11:39:13Z (GMT) No. of bitstreams: 2 Reis, Pamela Cristina de Sousa Guardiano.pdf: 1296512 bytes, checksum: 257e678ee16ea253856f4f88bba00934 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-09-25T11:39:13Z (GMT). No. of bitstreams: 2 Reis, Pamela Cristina de Sousa Guardiano.pdf: 1296512 bytes, checksum: 257e678ee16ea253856f4f88bba00934 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-02-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This study aimed to develop general microcapsules containing turmeric oleoresin and cluster derived from turmeric suspended in canola oil from concentrated whey protein, encapsulating material, and evaluate their antimicrobial activity. Turmeric gained fresh in the municipality of Mara Rosa underwent slicing and dehydration in an oven with air circulation. Obtained as a powder after successive washes with ethanol generated containing the ethanol extract of turmeric oleoresin which was rotaevaporado generating the turmeric oleoresin. This extract was subjected to vacuum filtration in order to remove solid fractions, and this filtration gave a cluster of turmeric. Both the extract containing oleoresin such as agglomerated product obtained by filtration were suspended in canola oil and used as core material for developing microcapsules. The microcapsules obtained had good sphericity concluding that the protein concentrate of whey was a good encapsulating material to the core studied. The microcapsules and free oleoresin extract were taken for analysis of antibacterial activity using agar diffusion test and found that the extract of turmeric oleoresin can be regarded as a potential antimicrobial agent, none of the microcapsules showed antimicrobial activity against fungus, but against the bacteria showed bacteriostatic action. We evaluated the behavior of the microcapsules determining their sorption isotherms, thermal stability and glass transition temperature. Before the study concluded that: the microcapsules oleoresin showed good thermal stability at temperatures that did not exceed 225 ° C, while the turmeric powder had good stability under temperatures slightly higher, up to 250 ° C, and these results do not conclusive, necessitating characterization studies of the patterns. / Este trabalho teve por objetivo geral desenvolver microcápsulas contendo oleorresina de cúrcuma e aglomerado derivado da cúrcuma suspensos em óleo de canola, a partir de concentrado de proteína do soro do leite, material encapsulante, e avaliar a sua atividade antimicrobiana. Cúrcuma in natura adquirida no município de Mara Rosa foi submetida a fatiamento e desidratação em estufa com circulação de ar. Obteve-se um pó que, após sucessivas lavagens com etanol gerou o extrato etanólico contendo oleorresina de cúrcuma que foi rotaevaporado gerando a oleorresina de cúrcuma. Esse extrato foi submetido a uma filtração a vácuo, a fim de se retirar frações sólidas, e obteve-se dessa filtração um aglomerado de cúrcuma. Tanto o extrato contendo oleorresina quanto esse produto aglomerado obtido pela filtração foram suspensos em óleo de canola e utilizados como material de recheio para desenvolvimento de microcápsulas. As microcápsulas obtidas apresentaram boa esfericidade concluindo que o concentrado proteico do soro de leite constituiu um bom material encapsulante para o núcleo estudado. As microcápsulas e o extrato de oleorresina livre foram levados para análise de atividade antibacteriana através de teste de difusão em ágar e concluiu-se que o extrato de oleorresina de cúrcuma pode ser tido como um agente antimicrobiano em potencial; nenhuma das microcápsulas apresentou ação antimicrobiana contra o fungo, mas contra a bactéria apresentaram ação bacteriostática. Foi avaliado também o comportamento das microcápsulas determinando suas isotermas de sorção, estabilidade térmica e temperatura de transição vítrea. Diante do estudo concluiu-se que: as microcápsulas de oleorresina apresentaram boa estabilidade térmica sob temperaturas que não ultrapassassem 225°C; enquanto que as de aglomerado de cúrcuma apresentaram boa estabilidade sob temperaturas um pouco maiores, até 250°C, sendo estes resultados não conclusivos, necessitando-se de estudos de caracterização dos padrões.