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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Peptide-Mediated Anticancer Drug Delivery

Sadatmousavi, Parisa 13 August 2009 (has links)
An ideal drug delivery system should contain an appropriate therapeutic agent and biocompatible carrier. In this study, we investigated the ability of the all-complementary self-assembling peptide AC8 in stabilizing the anticancer compound and determined the in-vitro therapeutic efficacy of the peptide-mediated anticancer drug delivery. The all-complementary peptide AC8 was designed based on the amino acid pairing principle (AAP), which contains hydrogen bonding, electrostatic, and hydrophobic interaction amino acid pairs. AAP interactions make the peptide capable of self-assembling into β-sheet structure in solution in a concentration dependent manner. Peptide solution concentration is a key parameter in controlling the nanoscale assembling of the peptide. The critical assembly concentration (CAC) of the peptide was found ~ 0.01 mg/ml by several techniques. The all-complementary peptide AC8 was found to be able to stabilize neutral state of hydrophobic anticancer compound ellipticine in aqueous solution. The formation of peptide-ellipticine complex was monitored by fluorescence spectroscopy at different mass ratios of peptide-to-ellipticine. The anticancer activity of the complexes with neutral state of ellipticine was found to show great anticancer activity against two cancer cells lines, A-549 and MCF-7. This peptide-mediated anticancer delivery system showed the induction of apoptosis on cancer cells in vitro by flow Cytometry.
72

Spausdintinio montažo plokščių surinkimo kokybės įvertinimas kompiuterine rega / Evaluation of Assembling Quality of Printed Circuit Boards Using Computer Vision

Zemblys, Raimondas 29 September 2008 (has links)
Elektronikos gamybos rinkoje produkcijos kokybei užtikrinti buvo pasikliaujama žmogaus vizualia apžiūra ir elektroniniais testais. Pasirodžius personaliniams kompiuteriams, gamybos pramonėje pradėta naudoti „kompiuterinė rega”. Procesas, kuriame naudojamas optinis vaizdo sensorius, pvz.: kamera, apibūdinamas kaip automatinė optinė kontrolė – AOK (angl. Automated Optical Inspection - AOI). Darbo tikslas - sukurti spausdintinio montažo plokščių kokybės įvertinimo sistemą panaudojant kompiuterinę regą, išrinkti spausdintinio montažo plokščių kokybės įvertinimui efektyviausius vaizdo apdorojimo algoritmus ir jų parametrus bei įvertinti jų efektyvumą. Taip pat nagrinėjama aplinkos veiksnių (apšvietimo, naudojamos techninės įrangos ir kt.) įtaka sistemos darbo efektyvumui. / Historically the electronics manufacturing market has relied on a combination of human visual inspection and electrical test methods to ensure product quality. With the advent of the personal computer, the use of "machine vision" in industrial applications gradually became more common. Process where optical sensors (i.e., cameras) are used to make specific pass/fail decisions is usually described as Automated Optical Inspection or AOI. There are discussed problems of designing AOI system in this paper. Main goal is to select most efficient image analysis algorithm and to study other parameters that have impact for designing reliable AOI system.
73

Síntese e caracterização de iodetos de diteluroéteres Análise da estrutura supramolecular / Synthesis and characterization of ditelluroethers iodides Analysis of supramolecular structure

Cargnelutti, Roberta 28 February 2012 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work describes the synthesis and characterization of thirteen new compounds belonging to the class of ditelluroethers iodides. The starting materials (ditelluroethers) were synthesized by a method few mentioned in the literature for the synthesis of this class of compounds. This methodology proved to be efficient once that ten new ditelluroethers were synthesized in satisfactory yields. Of these thirteen synthesized compounds, six had their structures determined by X-ray diffraction. From the structural analysis of these different ditelluroethers iodides we can conclude that the organization of the crystalline packing and the formation of the supramolecular assembling may vary with the carbon chain size between the tellurium atoms, aryl groups bond to the tellurium atom and the amount of molecular iodine used in the reaction. To ditelluroethers iodides of type [(PhTeI2)2(μ-CH2)] (1) with the participation of secondary bonds could be observed the formation of one-dimensional pseudo polymers. However, in ditelluroethers iodides in which the carbon chain contains four carbons, the formation of two-dimensional pseudo polymers to [(4-MeOC6H4TeI2)2(μ-C4H8)]·CH2Cl2 (12) or three-dimensional to [(PhTeI2)2(μ-C4H8)] (9) and [(2,6-MeOC6H3TeI2)2(μ-C4H8)] (13) were obtained. It was also verified the influence of the aryl group bonded to the tellurium atom, as the compound [(2,6-MeOC6H3TeI2)2](μ-CH2)] (4) which, instead of forming pseudo polymers, occurs the formation of molecular discrete structure. The use of different amounts of iodine also caused an influence on the crystalline packing as in [(PhTeI)2(μ-C3H6)(μ-O)] (5). / Este trabalho apresenta a síntese e caracterização de treze novos compostos pertencentes à classe dos iodetos de diteluroéteres. Os reagentes de partida (diteluroéteres) foram sintetizados por uma metodologia até então pouco citada na literatura para a síntese dessa classe de compostos. Essa metodologia mostrou-se eficiente uma vez que foram sintetizados dez novos diteluroéteres com rendimentos satisfatórios. Dos treze compostos sintetizados, seis tiveram sua estrutura determinada por difração de raios X. A partir da análise estrutural desses diferentes iodetos de diteluroéteres pode-se concluir que a organização do empacotamento cristalino e a formação de associações supramoleculares pode variar de acordo com o tamanho da cadeia carbônica entre os átomos de telúrio, os grupamentos arila ligados ao átomo de telúrio e a quantidade de iodo molecular utilizado na reação. Para iodetos de diteluroéteres do tipo [(PhTeI2)2(μ-CH2)] (1) com a participação das ligações secundárias observou-se a formação de pseudopolímeros unidimensionais. Entretanto, nos iodetos de diteluroéteres em que a cadeia carbônica é constituída por quatro carbonos, a formação de pseudopolímeros bidimensionais para [(4-MeOC6H4TeI2)2(μ-C4H8)]·CH2Cl2 (12) ou tridimensionais para [(PhTeI2)2(μ-C4H8)] (9) e [(2,6-MeOC6H3TeI2)2(μ-C4H8)] (13) foi obtida. Verificou-se também a influência do grupamento arila ligado ao átomo de telúrio, como no composto [(2,6-MeOC6H3TeI2)2](μ-CH2)] (4) no qual ao invés de formar pseudopolímeros ocorre a formação de uma estrutura molecular discreta. A utilização de diferentes quantidades de iodo também mostrou exercer influência no empacotamento cristalino como em [(PhTeI)2(μ-C3H6)(μ-O)] (5).
74

Utilisation de copolymères à blocs dans les cellules solaires organiques : morphologie, transport de charges et conversion photovoltaïque / Use of block copolymers in organic solar cells : morphology, charge transport and photovoltaic performances

Gernigon, Véronique 04 January 2012 (has links)
Les matériaux les plus répandus dans le domaine du photovoltaïque (PV) organique à base de polymères sont le poly(3-hexylthiophène) régiorégulier (rr-P3HT) et le [6,6]-phenyl-C61-butyric acide methyl ester (PCBM). La couche active est une hétérojonction en volume (BHJ) de nanodomaines interpénétrés accepteur d’électron (le PCBM) et donneur d’électron (le P3HT). Le contrôle de la morphologie de la couche active et de sa stabilité est un défi majeur pour le développement des cellules organiques et est au centre de ce travail de thèse.Dans un premier temps, nous avons cherché à contrôler la morphologie du mélange P3HT:PCBM via l’utilisation de compatibilisants. Deux familles de copolymères à blocs rigide et souple ont été étudiées. Elles ont en commun leur bloc rigide à base de P3HT et diffèrent par leur bloc souple. Pourla première famille, le bloc souple poly-butylacrylate est greffé de C60, ce qui lui confère une affinité chimique avec les domaines de PCBM, et la seconde famille a un bloc souple poly(4-vinylpiridine) (P4VP) non greffé en C60. De par son affinité chimique avec le C60, le PCBM se localisera préférentiellement au voisinage des domaines P4VP.Dans un deuxième temps, nous avons exploité les propriétés d’auto-assemblages des copolymères à blocs afin de les étudier en tant que matériaux photo-actifs. Nous avons cherché à appréhender l’influence de la nature du bloc flexible let de a taille des blocs souple et rigide sur l’organisation des copolymères ainsi que sur les propriétés de transport de charge et sur les performances PV. / Polymer/fullerene bulk heterojunction (BHJ) solar cells use an interpenetrating network of TT-conjugated electron-donor polymers and electron-acceptor C60 as photo-active layer. Currently, the most investigated blends are constituted of regioregular poly(3-hexylthiophene) (rr-P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). The nanostructured active layer determines to great extend the overall performance of the devices.First of all, we introduced rod-coil block copolymers as compatibilizer into P3HT:PCBM blends and investigate their influence on the blend morphology and the related photovoltaic performance. Two P3HT-based block copolymer families have been studied. The first one has a C60-grafted polybutylacrylate coil block and the second one is based on poly(4-vinylpyridine) (P4VP) coil block. The film morphology and device efficiencies are investigated as a function of copolymer content, P3HT/PCBM mass ratio and coil nature.A second possible route to obtain a stable donor/acceptor nanostructure consists of using semiconductor block copolymers as photoactive layer, since these materials are able to self-assemble into donor/acceptor BHJ by microphase separation. We explored P3HT-P4VP rod-coil block copolymers blended with PCBM in view of their utilization in photovoltaic devices. The copolymer selfassembles into nano-domains rich in either P3HT or P4VP, while the strong chemical affinity of P4VP with PCBM leads to an accumulation of the latter in the P4VP domains, providing them an acceptorcharacter. It is found that organized and thermally stable thin films, that exhibit ambipolar field effect mobilities, can be achieved for a specific rod/coil ratio.
75

Combination of self-assembling peptide hydrogel and autologous chondrocytes for cartilage repair : Preclinical study in a non-human primate model / Combinaison de peptides auto-assemblants et de chondrocytes autologues pour la réparation du cartilage : étude préclinique chez le primate non-humain

Dufour, Alexandre 19 November 2018 (has links)
Le cartilage a une capacité de régénération très limitée car il n'est pas vascularisé. Laréparation de ce tissu est un défi et les techniques chirurgicales actuelles sont insatisfaisantes à longterme. Le cartilage est donc un bon candidat pour l'ingénierie tissulaire. La transplantation dechondrocytes autologues (TCA) a été la première thérapie cellulaire développée en rhumatologie maiscette procédure implique une amplification des cellules qui aboutit à une perte du phénotypechondrocytaire (perte de l'expression du collagène de type II, protéine majoritaire du cartilage), auprofit d'un phénotype fibroblastique (caractérisé par l'expression du collagène de type I, retrouvé dansles tissus fibreux). La TCA conduit donc à une greffe de chondrocytes dédifférenciés produisant unfibrocartilage, dont les propriétés mécaniques sont inférieures à celles du cartilage articulaire.Aujourd'hui, les agences de santé au niveau international s'accordent pour dire que cette procédurenécessite d'être améliorée, par un meilleur contrôle du phénotype cellulaire et l'utilisation debiomatériaux pour mieux combler les lésions articulaires. Il s'agit donc de passer de la thérapiecellulaire à l'ingénierie tissulaire du cartilage.L'objectif de nos travaux a été d'évaluer la capacité d'un gel innovant de peptides autoassemblants,l'hydrogel IEIK13, à jouer le rôle de support pour des chondrocytes humains afin qu'ilsproduisent une matrice cartilage sous l'action de facteurs chondrogéniques. L'objectif visé a été lacréation d'un gel cartilage implantable par arthroscopie. Le défi a été de surmonter la dédifférenciationdes chondrocytes inhérente à leur amplification et incontournable pour augmenter le réservoircellulaire. L'amplification de chondrocytes humains a été réalisée en présence de FGF-2 et d'insuline(cocktail FI) puis leur redifférenciation a été induite en gel IEIK13 sous l'action de BMP-2, d'insuline etd'hormone T3 (cocktail BIT). C'est la combinaison sélective des deux cocktails qui permet la séquencedédifférenciation-redifférenciation. Le phénotype des chondrocytes et la nature de la matriceextracellulaire synthétisée en gel ont été évalués dans un premier temps in vitro, par des analyses dePCR en temps réel, Western-blots et d'immunohistochimie. Dans un second temps, nous avonstransplanté le gel cartilage dans des lésions articulaires de genou d'un modèle original de primate nonhumain(singe cynomolgus), un type de gros animal dont la posture et le fonctionnement desarticulations s'apparentent à l'homme. Nos études d'imagerie non invasive (telle qu'elle est pratiquéechez l'homme) et immunohistochimiques trois mois après implantation montrent une réparationsatisfaisante des lésions, en comparaison avec les lésions laissées non comblées. L'ensemble de nosrésultats montre pour la première fois que l'hydrogel IEIK13 est un biomatériau favorable pourreconstruire le cartilage et que le primate non-humain est un modèle préclinique unique pour évaluerl'efficacité de l'ingénierie tissulaire du cartilage / Cartilage is not vascularized and presents poor capacity of self-regeneration. Repairing thistissue is a challenge and current surgical techniques are not satisfactory in the long term. Cartilage isthus a good candidate for tissue engineering. Autologous chondrocyte transplantation (ACT) was thefirst cell therapy developed for cartilage repair. This procedure implies amplification of cells whichresults in chondrocyte dedifferentiation (loss of expression of type II collagen, the major protein ofcartilage and acquisition of expression of type I collagen, the major protein found in fibrous tissues).Thus, ACT results in implantation of fibroblastic cells producing fibrocartilage with biomechanicalproperties inferior to native articular cartilage. The international health agencies agree that ACT needsto be improved with better control of the chondrocyte phenotype and use of biomaterials. Therefore,cell therapy of cartilage needs to move towards tissue engineering of cartilage.The objective of our study was to evaluate the capacity of an innovative self-assemblingpeptide (IEIK13) to support cartilage matrix production by human chondrocytes. Our goal was to createa cartilage gel that can be implanted by arthroscopy. A main challenge was to meet the problem ofchondrocyte dedifferentiation induced by cell amplification necessary to increase the cellularreservoir. Amplification of human chondrocytes was performed in the presence of FGF-2 and insulin(cocktail FI), and redifferentiation was subsequently induced in IEIK13 gel with BMP-2, insulin, andtriiodothyronine T3 (cocktail BIT). The specific combination of these two cocktails alloweddedifferentiation-redifferentiation of chondrocytes. The status of the chondrocyte phenotype and thenature of the extracellular matrix secreted in gel were first assessed in vitro by real-time PCR, Westernblottingand immunhostochemistry analyses. With a view of clinical application, we then transplantedIEIK13-engineered cartilages into defects created in knees of an original model of non-human primate(cynomolgus monkey), a type of large animal whose anatomy and biomechanics mimic human. Ournon-invasive imaging analyses and our inmmunohistochemical studies performed three months afterimplantation show correct reparation of the lesions, in comparison with the defects left untreated.Altogether, our results demonstrate for the first time that IEIK13 is a suitable biomaterial for cartilagerepair and that cynomolgus monkey represents a unique preclinical model to evaluate efficiency ofcartilage tissue engineering.
76

Etudes d'auto-assemblages polydiacétylèniques et applications biologiques / Polydiacetylenic self-assemblies and biological applications

Morin-Picardat, Emmanuelle 02 July 2012 (has links)
La dualité hydrophobe/hydrophile des molécules amphiphiles est à l’origine de leur autoassemblage en solution, sous forme de nombreuses structures supramoléculaires, telles que les micelles. Ce travail de thèse présente la formation, la caractérisation et l’étude de nouvelles micelles diacétylèniques photopolymérisables. Une première partie décrit ainsi lasynthèse de nouvelles micelles cationiques et l’étude de leur utilisation en tant qu’agent de transfert de gènes. Dans une seconde partie, nos travaux présentent l’étude de micelles polydiacétylèniques, porteuses de têtes polaires octaéthylèneglycol, comme potentiel système de délivrance de médicament. Les propriétés d’encapsulation de ces micelles ont été évaluées en présence d’un dérivé fullerène fluorescent. Puis, l’incorporation d’une sonde membranaire dans leur couronne lipophile a permis de réaliser une étude de leurs propriétés de délivrance in vitro. Une étude préliminaire de leur biodistribution in vivo a également été réalisée par tomographie à émission monophotonique grâce à la chélation d’un isotoperadioactif sur la surface des micelles. Enfin une dernière partie présente l’analyse de deux nouveaux auto-assemblages tubulaires obtenus au cours de nos travaux. / The hydrophobic/hydrophilic duality of amphiphilic molecules is at the origin of their selfassembly in solution, into many supramolecular structures such as micelles. This thesis presents the formation, characterization and study of new photopolymerizable diacetylenic micelles. The first part describes the synthesis of new cationic micelles and the study of theiruse as gene transfer agent. In the second part, our work presents the study of polydiacetylene micelles, bearing polar heads octaétylèneglycol as potential drug delivery system. The encapsulation properties of these micelles were first evaluated in the presence of a fluorescent fullerene derivative. Then, the incorporation of a membrane probe in their lipophilic shell has allowed a study of their in vitro delivery properties. Finally a study of their in vivo biodistribution was also carried out by single photon emission tomography through the chelation of a radioactive isotope on micelle surface. Finally the last part presents theanalysis of two new tubularself-assemblies, obtained during our work.
77

Conception, synthèse et étude de dérivés de C60 fonctionnalisés : applications biologiques et développement méthodologique / Design, synthesis and study of functionalized C60 : biological applications and methodological development

Sigwalt, David 26 March 2013 (has links)
Notre équipe a récemment développé une méthode polyvalente permettant de préparer des dérivés complexes de C60 hexa-adduits fonctionnalisés. Cette méthodologie permet d’obtenir des produits aux caractéristiques originales. Le C60 central agit comme un support central peu réactif, autour duquel des fonctionnalités sont réparties dans un espace octaédrique parfaitement défini. La première partie de ce travail de thèse a consisté à exploiter cette méthodologie pour créer des C60 hexa-adduits polycationiques aux propriétés de transfection remarquables. Dans un second temps, les dendrons polyamines synthétisés ont été mis à profit pour créer des structures supramoléculaires de C60 hexa-adduits, sous forme micellaire. Par la suite, l’étude de ces assemblages a orienté nos investigations vers l’élaboration de dérivés de C60 hexa-adduits mannosylés multivalents résultant d’un assemblage supramoléculaire, dont leurs possibles applications biologiques sont actuellement à l’étude. En parallèle une synthèse covalente a permis d’obtenir un «équivalent dendritique» de C60 hexa-adduit multimannosylé. Partant du constat que notre méthodologie est efficace principalement pour des dérivés de C60 hexa-adduits qui ont une régio-sélectivité particulière, la dernière partie a été consacrée au développement de nouvelles voies de synthèses qui pourront permettre de créer des dérivés de C60 avec un contrôle régio-sélectif original. / Our team has recently built a polyvalent method that gives complex functionalized C60 hexa-adducts. This methodology permits to obtain products with original features. C60 acts as an inert scaffold, around which functionnalities are distributed in a well-defined octahedral space. The first part of this thesis describes exploitation of this methodology to create polycationics C60 hexa-adducts, which have shown remarkable gene delivery capabilities. Next, the synthetized polyamine dendrons were used to build supramolecular structure of C60 hexa-adducts, as micellar forms. The study of these self-assembled structures has guided us to design micelles of mannosylated C60 hexa-adducts, which biological applications are under investigation. In parallel a covalent synthesis has furnished a dendrimers-like multimannosylated C60 hexa-adduct. Based on the observation that our methodology to create C60 hexa-adduct is efficient only for a specific regio-selectivity, the last part of this thesis was devoted to the development of new synthetic routes to obtain C60 derivates with an original regio-selective control.
78

Plánování účetních výkazů s ohledem na vývoj hospodářské činnosti podniku / The planning of accounts with regard to development on economic aktivity

POLÁČEK, Jan January 2007 (has links)
The planning of accounts for the following 5 years (from 2006 till 2010). The accounts consist of balance sheet, income statement and cash flow statement. Items of accounts are planned according to the developement of the choosen company and real market conditions. This dissertation describes not only plannig of accounts, but also method of assembling accounts.
79

Investigação do efeito de moléculas auto-organizáveis na resistência à corrosão da liga de Alumínio 1050 / Investigation on the of effect of self assembling molecules on the corrosion resistance of the 1050 aluminium alloy

Margarida Szurkalo 16 December 2009 (has links)
Tratamentos de superfície são técnicas amplamente utilizadas com a finalidade de aumentar a resistência à corrosão de materiais metálicos. No caso específico do alumínio e ligas de alumínio, o tratamento com cromo hexavalente é um dos processos mais utilizados. Isso, em razão da eficiência e da facilidade de aplicação desse processo. Entretanto, em virtude de restrições ambientais e do elevado custo de tratamento de resíduos gerados neste processo, métodos alternativos para sua substituição vêm sendo avaliados. Neste contexto, o presente estudo investigou o processo de formação e proteção à corrosão fornecida por filmes de moléculas autoorganizáveis de compostos à base de fosfonatos sobre a liga de alumínio 1050. Para definir as condições do tratamento foram utilizadas medidas de condutividade e de ângulo de contato, juntamente com ensaios eletroquímicos. Técnicas eletroquímicas, especificamente: medidas de variação do potencial a circuito aberto (PCA), espectroscopia de impedância eletroquímica (EIE) e polarização potenciodinâmica foram utilizadas para avaliar a proteção à corrosão. Os diagramas experimentais de impedância foram interpretados utilizando circuitos elétricos equivalentes que simulam modelos do filme de óxido que se forma na superfície da liga. Os resultados fornecidos com a liga tratada com moléculas auto-organizáveis foram comparados com resultados obtidos em iguais condições com amostras da liga sem qualquer tratamento ou cromatizada com Cr(VI) e mostraram que o tratamento com moléculas auto-organizáveis aumenta significativamente a resistência à corrosão da liga e apresenta, em determinadas condições, desempenho próximo ao fornecido pelo processo de cromatização. / Surface treatments are widely used to increase the corrosion resistance of metallic materials. Specifically for aluminum and aluminum alloys, treatment with hexavalent chromium is one of the most used, due to its efficiency and ease of application. However, because of environmental restrictions and the high cost involved in the treatments of waste generated in this process, alternative methods for its replacement are necessary. In this context, this study investigated the effect of the surface treatment with self-assembling molecules (SAM) based on phosphonate compounds on the corrosion of the 1050 aluminum alloy. The conditions adopted for the SAM treatment were determined by conductivity and contact angle measurements, besides electrochemical experiments. Electrochemical techniques, specifically: measurement of the open circuit potential (OCP) variation with time, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves were used to evaluate the corrosion resistance of the 1050 aluminum alloy exposed to SAM treatment The experimental impedance diagrams were interpreted using equivalent electrical circuit models that simulate film that is formed on the alloy surface. The results of the samples treated with SAM were compared with those of samples either without any treatment or treated with chromatizing conversion coating with Cr(VI) and showed that the first treatment significantly increased the corrosion resistance of the aluminum alloy and approached that of chromatizing with Cr(VI) process.
80

Assemblage nanoparticules lipidiques solides-polysaccharide : étude des propriétés physico-chimiques pour la vectorisation d’un polyphénol / Solid lipid nanoparticles-polysaccharide assembling : study of physicochemical properties for the vectorization of a polyphenol

Hajjali, Hassan 16 December 2015 (has links)
Ce travail porte sur la conception d'un système lipo-polysaccharidique sous forme d'un assemblage de taille micrométrique entre des nanoparticules lipidiques solides (SLNs) et un biopolymère. Le but est de formuler un vecteur pouvant : transporter un principe actif hydrophobe, résister aux conditions gastriques, et permettre un relargage contrôlé en conditions spécifiques. Le choix de la molécule active s'est porté sur un polyphénol, la curcumine, pour ses activités anti-oxydantes et anti-inflammatoires. Etant hydrophobe, la curcumine a été encapsulée dans des nanoparticules de beurre de karité qui est un lipide d'origine naturelle et solide à température ambiante. Les systèmes lipidiques ne résistant pas aux conditions gastriques, les nanoparticules ont été incluses dans une matrice de chitosane sous forme d'un assemblage micrométrique contrôlé par des interactions électrostatiques. Ce polymère naturel, chargé positivement grâce à la présence de groupements amines, résiste aux attaque des enzymes gastriques et présente des interactions spécifiques avec la muqueuse intestinale et notamment les mucines permettant ainsi un ciblage vers l'intestin et le côlon. La première partie de cette étude est focalisée sur le système beurre de karité-curcumine en absence de chitosane. L'effet du polyphénol sur la cristallisation du lipide a tout d'abord été étudié. L'influence de la composition du mélange ternaire (beurre de karité, tensioactif, eau) sur les propriétés des nanoparticules formées a ensuite été étudiée en utilisant la méthodologie des plans de mélanges. Cela a permis de contrôler la taille des SLNs formulées et de mettre ensuite en évidence l'influence de la taille des particules sur le taux d'encapsulation de la curcumine. La seconde partie est axée sur l'assemblage entre les nanoparticules et le chitosane. Des particules micrométriques ont ainsi été obtenues par interactions électrostatiques entre les SLNs encapsulant la curcumine et stabilisées par des phospholipides et le chitosane / This work deals with the design of a lipo-polysaccharidic system as a micrometric assembly between solid lipid nanoparticles (SLNs) and a biopolymer. The aim is to formulate a vector can: carry a hydrophobic active molecule, resist to gastric conditions, and allow a controlled release in specific conditions. Choosing the active molecule is carried on a polyphenol, curcumin, for its antioxidant and anti-inflammatory activities. Being hydrophobic, curcumin was encapsulated in shea butter nanoparticles, which is a natural lipid and solid at room temperature. Lipid nanocarriers are not resistant to gastric conditions; the nanoparticles have been included in a chitosan matrix in the form of a micrometric assembly controlled by electrostatic interactions. This natural polymer, positively charged due to the presence of amine groups, is resistant to attack by gastric enzymes and has specific interaction with the intestinal mucosa and in particular the mucin which can be useful as a carrier for curcumin in colon targeted drug delivery. The first part of this study focused on shea butter–curcumin system with the absence of chitosan. The effect of polyphenols on the lipid crystallization was studied. The influence of the composition of the ternary mixture (shea butter, surfactant, water) on the properties of the nanoparticles was then investigated by using the response surface methodology. This helped to control the size of SLNs and then to show the influence of particle size on the encapsulation efficiency of curcumin. The second part focuses on the assembling between the nanoparticles and chitosan. Micrometric particles were obtained through electrostatic interactions between SLNs encapsulated curcumin and chitosan

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