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Dissertations / Theses on the topic 'Nanogels'
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Lee, Jin Cho Moo J. "Polymeric nanogels as gene carriers." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2007. http://dc.lib.unc.edu/u?/etd,1239.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2007.<br>Title from electronic title page (viewed Mar. 26, 2008). "... in partial fulfillment of the requirement for the degree of Doctor of Philosophy in the Division of Molecular Pharmaceutics at the School of Pharmacy." Discipline: Molecular pharmaceutics; Department/School: Pharmacy.
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Liu, Chao. "Multilayer Based Nanogels and Bio-lubricants." Doctoral thesis, KTH, Yt- och korrosionsvetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-140688.
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Surface chemistry plays an important role in numerous technological innovations, and gives the ability to modify and control surface and interface properties. Layer-by-Layer (LbL) self-assembly is a simple concept that can provide a route to versatile combination of materials as well as fine control of film thickness, hydrophobicity, thermal, optical and electrical properties. This methodology has thus received attention from both academic and industrial experts. A large variety of polymers, proteins and nanoparticles can be utilized in the LbL process. In my PhD-thesis work I made use of the LbL technique to build surface grafted nanogels and bio-lubricant films. Various surface sensitive techniques have been applied in this PhD thesis work. The three main methods were quartz crystal microbalance with dissipation (QCM-D), total internal reflection Raman (TIR-Raman) spectroscopy, and atomic force microscopy (AFM). In lieu of conventional methods such as reflectometry or ellipsometry, we have combined data obtained from QCM-D and TIR-Raman to gain information on wet and dry LbL films as well as their water content. The relatively new AFM imaging mode known as PeakForce QNM was used to investigate topographical and nano-mechanical properties of LbL films. The colloidal probe technique was implemented with AFM for normal and lateral force measurements. It is becoming increasingly clear that biopolymers are important for a sustainable society since they are renewable, have useful properties and often are environmentally benign. One main part in this thesis work was to fabricate thin chitosan (CHI) nanogels covalently attached to solid surfaces. This was achieved by first assembling a chitosan/poly(acrylic acid) multilayer using silane chemistry and the LbL method. Next, the chitosan molecules were selectively cross-linked in the film, and finally poly(acrylic acid) was (partly) rinsed out of the nanogel. The final composition and the responsiveness of the nanogel to pH and ionic strength changes were found to depend on the cross-linking density. Statistical analysis, known as target factor analysis, was used to analyze TIR Raman spectra and draw conclusions about e.g. the composition of multilayers during the build-up process, and the kinetics of cross-linking of chitosan. The other main part in this thesis work also utilized the LbL methodology, but here the main goal was to gain understanding on the unprecedented lubrication of synovial joints. It is in general terms due to a sophisticated hierarchical structure of cartilage combined with synergistic actions of surface-active components present in the synovial fluid, but many aspects of this fascinating biotribological system remain poorly understood. I focused on the lubricating ability of synovial fluid components, and in particular on the association of two components of the synovial fluid, hyaluronan and dipalmitoyl phosphatidyl choline (DPPC), in bulk solution and at interfaces. We found that hyaluronan associated with DPPC vesicles in bulk and adsorbed to supported DPPC bilayers, and that the LbL method could be utilized for forming composite layers of these two components. These composite layers had very favorable lubrication properties, with a low friction coefficient as low as 0.01, and they were also sufficiently stable to shear and load up to the pressure that broke healthy cartilage.<br><p>QC 20140130</p>
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Messager, Léa. "Nanogels de polysaccharides pour la délivrance d’insuline." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14690/document.
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Les nanogels sont de bons candidats pour la délivrance d’actifs. Ces réseaux de polymères réticulés et de taille nanométrique, sont gonflés d’eau. Ils sont donc capables d’encapsuler une protéine à l’intérieur de leurs pores et de la libérer en fonction de l’état de gonflement du réseau. Cet état peut être modulé par la densité de réticulation du réseau ou par l’application d’un stimulus externe tel que le pH, la température ou encore une biomolécule telle que le glucose. Ainsi, les nanogels sensibles au glucose se présentent comme des candidats idéaux pour administrer l’insuline de façon asservie à la glycémie. Afin de satisfaire aux critères de biocompatibilité et de biorésorption des vecteurs, nous avons choisi de développer des nanogels à base de polysaccharide, en particulier à base d’acide hyaluronique (HA). Ceux-ci sont obtenus par réticulation du HA, préalablement modifié par des fonctions réticulables telles que les méthacrylates, dans des nanogouttes d'émulsion eau-dans-huile. Des nanogels de taille et de porosité modulables ont été synthétisés grâce à un bon contrôle 1) de la modification chimique des précurseurs par des fonctions réticulables (taux de méthacrylation), 2) de l’émulsion matricielle (taille, stabilité), 3) des conditions de réticulation par photopolymérisation gouvernant le taux de conversion des méthacrylates. Ce savoir-faire a ensuite été appliqué à la synthèse de nanogels modifiés par des dérivés de l’acide phénylboronique, ligand du glucose, afin d’obtenir des matériaux dont le taux de gonflement varie en fonction de la glycémie. L’intérêt applicatif de ces objets a été évalué vis-à-vis des propriétés d’encapsulation de l’insuline, de dégradabilité enzymatique, et de biocompatibilité<br>Nanogels are an attractive class of delivery systems. These soft particles, made of highly swollen polymer network, can physically entrap a drug and release it at a rate depending on its diffusion though the network. Therefore, any change in the swelling degree can trigger the release kinetics. This parameter can be tuned by modifying the density of cross-links in the gel matrix or by changing the environmental conditions such as pH, temperature or analyte such as glucose. Thus, glucose-responsive nanogels are good candidates to be used as self-regulated systems for insulin delivery. To fulfill both biocompatibility and biodegradability criteria, our attention has been focused on the design of new nanogels made of polysaccharides, in particular made of hyaluronic acid (HA), as a main constituent. HA was at first covalently modified with polymerizable methacrylate functions and confined in nanoreactors during photopolymerization using water-in-oil miniemulsions as template. Biodegradable nanogels with a well-defined size and various cross-linking degrees were thus achieved, thanks to a good control of 1) the chemical modification of HA with methacrylates (degree of methacrylation) 2) the emulsion template (size, stability), 3) the photopolymerization conditions which governed the conversion rate of the polymerization. Further modification of the polysaccharide with phenylboronic acid as a glucose-sensitive group yielded nanogels whose swelling behavior could vary as a function of glucose concentration. These systems were further studied as insulin delivery systems. Moreover, their biodegradability, stability and biocompatibility were assessed
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Rippe, Marlène. "Systèmes transporteurs de principes actifs hydrophobes à base de glycoaminoglycanes thermosensibles : vers une plateforme polyvalente de délivrance." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAV004/document.
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Dans le domaine des systèmes d’administration de principes actifs, les nanovecteurs formés par auto-association en milieu aqueux de polymères biocompatibles amphiphiles sont apparus comme l’un des systèmes transporteurs de principes actifs (PA) hydrophobes les plus prometteurs. Ces systèmes offrent plusieurs avantages tels qu'une meilleure solubilité du PA hydrophobe dans l'eau, une diminution des effets secondaires et une amélioration de la libération dans les tissus tumoraux grâce à l’effet de perméabilité et de rétention tissulaire (effet EPR). À cet égard, les nanogels sensibles aux stimuli sont des plateformes attrayantes pour l'administration de médicaments en raison de leur capacité à modifier leurs propriétés physiques et/ou chimiques en réponse à un stimulus externe tel que la lumière, l’application d’un champ magnétique, une variation de pH ou de température. Les polymères thermosensibles sont particulièrement intéressants en raison de leur capacité à subir une transition de phase réversible sans avoir besoin de réactifs supplémentaires. Dans ce contexte, nous avons développé et étudié une nouvelle classe de nanogels thermosensibles, biocompatibles et biodégradables à base de glycoaminoglycanes (GAGs) en modifiant le squelette polysaccharidique avec un copolymère thermoresensible de méthacrylate de di(éthylène glycol) et de n-butylméthacrylate. Celui-ci a été conçu pour obtenir des nanogels stables à température ambiante. La voie de synthèse polyvalente a également permis la réticulation de la couronne afin de figer leur structure. Le choix des GAGs, composant la couronne hydrophile peut être exploité pour contrôler leur comportement biologique. Dans l’objectif d’utiliser ces systèmes en tant que plate-forme polyvalente pour la délivrance de principes actifs et d’autres molécules d'intérêt, nous avons étudié la possibilité d’incorporer des nanoparticules d'oxyde de fer pour des applications de guidage magnétique, d’imagerie et de traitement par hyperthermie. Les synthèses du composant magnétique ainsi que la conception du nanovecteur sont des étapes clés pour réaliser un système de délivrance magnétique capable de réaliser un ciblage efficace<br>In the field of drug delivery systems, polymeric nanogels obtained by the self-assembly of biocompatible amphiphilic polymers in water have emerged as one of the most promising nanocarriers for various hydrophobic drugs. These systems offer several advantages such as enhanced hydrophobic drug solubility in water, decreased side effects, and improved drug delivery to tumor tissues via the enhanced permeability and retention (EPR) effect. In this regard, stimuli-responsive polymeric nanogels are attractive platforms for drug delivery due to their ability to change their physical and/or chemical properties in response to an external stimulus such as light, magnetic field, pH or temperature. Thermoresponsive polymers are particularly interesting due to their ability to undergo a reversible thermally-induced phase transition without the need of additional reagents. In this context, our aim was to engineer and to study a new class of thermoresponsive, biocompatible and biodegradable nanogels based on glycoaminoglycans (GAGs) through the modification of the polysaccharide backbone with a thermoresponsive copolymer of di(ethylene glycol) methacrylate (DEGMA) and n-butylmethacrylate (BMA)). The latter was properly designed to obtain stable nanogels at room temperature. The versatile synthetic route to nanogels also allowed their further shell-crosslinking to capture the nanogel structure at low temperature. The choice of the GAGs forming the hydrophilic shell can be exploited to control their biological behavior. In order to use these systems as a versatile platform for delivery of active ingredients and other molecules of interest, we investigated the possibility of incorporating iron oxide nanoparticles for magnetic guidance, imaging and hyperthermia treatment. The syntheses of the magnetic component as well as the design of the nanocarrier are key steps to achieve a magnetically-responsive nanodelivery system capable of efficient targeting
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Muratalin, Marat. "Stimuli-responsive nanogels for environmental and pharmaceutical applications." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/10190.
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The term microgel has been widely used to describe particles that swell but do not dissolve in a solvent. Traditionally they can be anything from 100 nm – 100 μm in size. This project is devoted principally to investigation of the swelling/deswelling properties of largely submicron poly(N-isopropylacrylamide) [PNIPAM] microgel particles and its derivatives and also poly(2-vinylpyridine) [PVP] microgel particles. PNIPAM microgel particles are temperature-responsive because of the hydrophobic isopropyl group and the hydrophilic amide group present in its side chains. PVP microgel particles are pH-responsive due to the pyridine groups. Surfactant free emulsion polymerization (SFEP) and emulsion polymerization techniques were employed in order to copolymerize PNIPAM with acrylic acid (AA), with 3-acrylamidophenylboronic acid (3-APB) and (3-acrylamidopropyl)trimethylammonium bromide (ATMA) and with 1-vinylimidazole (VI). The resultant microgel particles exhibited multi-responsive behaviour being sensitive to changes in temperature, pH and the PNIPAM-co-3-APB-ATMA microgels were sensitive to concentration of glucose, whilst the PNIPAM-co-VI microgels were sensitive to certain metals, copper in particular. These microgel particles were characterized using dynamic light scattering (DLS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The behaviour of the particles under various conditions of temperature, pH, glucose and metal ion are described and discussed in this work and several observations, such as swelling/deswelling transitions of PNIPAM-co-VI and PNIPAM-co-3-APB-ATMA with increase of concentration of added copper (II) and glucose respectively, were reported for the first time. The microgel containing AA exhibit characteristic temperature-sensitive behaviour with volume phase transition temperature (VPTT) being in the range of 35o-40oC and showed pH-sensitive features as the particles collapsed at low and swelled at high pHs. The PNIPAM-co-VI microgels undergo swelling before the concentration of Cu2+ reaches 0.3 g/L due to adsorption of the cations inside the particle which leads to charging up the internal phase of the microgel. Hence, the repulsion forces of positively charged Cu (II) ions are dominating over contraction forces of complex binding. However, at higher concentrations of copper (II) ions the binding forces of complexation between Cu2+ and imidazole groups of the microgels are leading to conformation of the microgel backbone, and hence weaker polymer-solvent interactions. Therefore, it is favourable that solvent would be forced out of the particle resulting into the collapse. In addition, the copper (II) uptake was calculated and the uptake was found to be well described by the Langmuir adsorption isotherm. The impact of other metal ions, such as nickel, zinc, iron and silver, was also investigated. The microgels swelled upon addition low concentrations of corresponding metal ions, however aggregation has been observed at higher concentrations. The microgels containing various concentration of VI were also examined on sensitivity to the temperature and pH changes. The investigation of such microgels with increasing temperature showed similar behaviour to those containing AA as the microgel particles shrunk continuously and the LCST has been shifted to higher temperatures (in the range of 35o-45oC). The particle size of these microgels was also investigated as a function of pH; the microgel particles swelled at low and collapsed at high pHs. The particle size of the PNIPAM-co-3-APB-ATMA microgels was investigated both as a function of temperature and glucose concentration. The microgels showed typical behaviour of the PNIPAM microgels copolymerized with functional monomer, which were 3-APB and ATMA, by continuous shrinking with increasing temperature and shifted LCST towards higher temperatures. Additionally, these microgels showed swelling behaviour with the increase of glucose concentration at physiological conditions, i.e. particles swelled in the range of glucose concentration between 0.1 and 10 mmol/L at 35oC and pH 7.5. The behaviour of these microgels was also investigated at 35oC and pH 8.5 as a function of glucose concentration. Although the swelling of the particles was slightly larger at pH 8.5, considerable swelling was also observed at pH 7.5 making them the first microgel system to be glucose sensitive at physiological pH and temperature.
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Shi, Aibin. "Synthesis and bioactivities of substituted quinolines and nanogels." Diss., Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1638.
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Oehrl, Alexander [Verfasser]. "Polyglycerin-Based Nanogels for Protein Encapsulation / Alexander Oehrl." Berlin : Freie Universität Berlin, 2020. http://d-nb.info/1214641296/34.
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Weiss-Maurin, Mathilde. "Synthèse de nanogels à base de poly(liquides ioniques), par copolymérisation radicalaire réticulante contrôlée par le cobalt, pour des applications de revêtement." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0152/document.
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La synthèse de nanogels par voie directe est étudiée par la copolymérisationradicalaire réticulante contrôlée par le cobalt (CMRCcP) d’un monomère monovinylique et d’unréticulant divinylique. La synthèse de nanogels globulaires a été réalisée en utilisant unsystème de co-monomères soit neutres (acétate de vinyle et adiapte de divinyle) soit liquidesioniques. Le contrôle de la polymérisation est vérifié dans tous les cas, les liaisons C-Cosituées aux extrémités des chaînes polymères ont été réactivées, afin de former des nanogelsde « seconde-génération ». Dans le cas de monomères liquides ioniques, différents contreanionsont été utilisés afin de jouer sur l’hydrophilie des co-monomères : la CMRCcP dubromure de N-vinyl-3-ethyl imidazolium (VEtImBr) et du bromure de 1,13-divinyl-3-decyldiimidazolium (DVImBr) a été réalisée dans l’eau, à 30 °C, pour former des nanogelspoly(VEtImbr-co-DVImBr) hydrophiles. Les propriétés antibactériennes de ces nanogels ontété étudiées.Les pendants hydrophobes de ces nanogels à base de PILs ont été synthétisés via laCMRCcP directe, dans l’acétate d’éthyle, de co-monomères contenant des contre-anionsbis(trifluromethanesulfonyl)imide (NTf2-). La capacité à former des surfaces poreusesordonnées de ces nanogels hydrophobes poly(VEtImNTf2-co-DVImNTf2) a été examinée, ainsique leur conductivité ioniques en films minces.Des copolymérisations ‘mixtes’ ont également été étudiées, dans l’optique de formerdifférentes architectures nanogels en utilisant des co-monomères ayant des réactivités trèsdifférentes<br>The syntheses of globular nanogels were first investigated under mild conditions,using a mono- and a divinyl co-monomer with similar reactivities. CMRCcP was implementedon either neutral (vinyl acetate (VAc) and divinyl adipate (DVA)) co-monomers, or ionic liquidco-monomers. Control over each polymerization was ascertained, and dormant cobaltcarbonchain-ends could be re-activated to form “second-generation” nanogels. CMRCcP ofN-vinyl-3-ethyl imidazolium bromide (VEtImBr) and 1,13-divinyl-3-decyl diimidazoliumbromide (DVImBr) was achieved in water at 30 °C, leading to hydrophilic poly(VEtImBr-co-DVImBr) nanogels. The antibacterial activity of these cross-linked structures wasinvestigated. The hydrophobic pendants of these PIL-based nanogels were synthesized viadirect CMRCcP in ethyl acetate, using bis(trifluromethanesulfonyl)imide (NTf2-) counteranions. An array of these poly(VEtImNTf2-co-DVImNTf2) nanogels was then investigated aspossible coatings for porous patterned surfaces, and their ionic conductivity assessed.Different cross-linked architecture were approached, using a mono- and a divinyl comonomersof completely different reactivities
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Ray, Judith Victoria. "Novel molecular imprinted nanogels as drug delivery vehicles for tamoxifen." Thesis, Queen Mary, University of London, 2014. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8856.
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The field of nanomedicine has witnessed an incredible expansion, from a total market value in 2003 of $500 million expected to rise to $160 billion by 2015 (Global Industry Analysts, Inc.). The nanomedicine industry is forecasted to grow and have a significant impact on the economy, with sectors such as biomaterials, diagnostics and drug delivery expected to play a major role. This thesis gives a detailed account of the synthesis and characterisation of molecularly imprinted nanogels for drug delivery. Their toxicity and potential use as a targeted carrier to cancerous cells is evaluated. Initially an overview of nanomaterials and their uses in many areas such as agriculture, energy storage and technology are discussed. The impact of nanomaterials on the life sciences is examined; in particular their application in drug delivery is focussed upon. Chapters 2, 3 and 4 make up the results and discussion of this work. Chapter 2 focuses on developing the synthesis of the acrylamide based nanogels and, vitally, incorporating a suitable fluorescent tag in order to track the nanogels in vitro and in vivo. Fundamentally toxicity studies carried out on the nanogels, both in vitro and in vivo in Danio rerio (zebrafish) are reported in Chapter 3 to ensure the nanogels are biocompatible. Chapter 4 introduces an innovative approach, molecular imprinting, to incorporating a drug into the nanogels. The upload and release of Tamoxifen (a drug used to treat breast cancer) at reduced pH, was also analysed. Finally future development of the carrier is discussed and key issues that need to be addressed.
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Khlebtsov, B. N., and E. V. Panfilova. "Synthesis and Study of PNIPAM Nanogels Incorporated with Colloidal Silver." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35090.
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Composite nanoparticles consisting of polymer gels with incorporated silver nanoparticles have been synthesized. The synthesis comprises two main stages. Initially, monodisperse hydrogel particles with a controlled diameter of approximately 500 nm are obtained by N-isopropylacrylamide polymerization. Then, silver ions are reduced on the surface of the polymer network. Variations in the concentration ratio between reductants and silver nitrate make it possible to produce silver nanoparticles with sizes in a range of 10-30 nm and different packing densities on the gel particle surface. The resultant nanocomposites have been studied by transmission electron microscopy, spectrophotometry, and dynamic light scattering. Depending on the size and packing density of the silver nanoparticles on the polymer particle surface, the plasmon resonance of the nanocomposites varies in a range of 420-750 nm, which determines variations in the color of the colloid from yellow, orange, and red to blue and blue-green. After the inclusion of silver nanoparticles, nanogels of poly(N-isopropylacrylamide) retain their capability for thermosensitive phase transition with a lower critical mixing temperature of 31 °C.
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Costamagna, Federica. "Colloidal stability, intracellular fate and toxicology of drug nanocarriers - Application to polymerized micelles and organometallic nanogels Nanotoxicology at the particle/micelle frontier: influence of core-polymerization on the intracellular distribution, cytotoxicity and genotoxicity of polydiacetylene micelles." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS128.
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Une compréhension approfondie de la stabilité colloïdale est nécessaire pour concevoir des nanoparticules pour la vectorisation de molécules actives. En particulier, prévoir le comportement in vivo des particules (désagrégation ou agrégation) est fondamental pour prédire l’efficacité et la toxicité des nanoformulations. Les objectifs de cette thèse concernaient (1) l’amélioration de la stabilité colloïdale en conditions physiologiques et (2) l’étude in vitro du comportement biologique de deux types de nanovecteurs : nanogels à base de chitosane-fer et micelles de polydiacétylène<br>A thorough understanding of the colloidal stability is important to design nanoparticles for drug delivery purposes. In particular, anticipating the in vivo particles disassembly or aggregation is fundamental in order to predict efficacy and toxicity of the nanoformulations. The objectives of this thesis concerned (1) the improvement of the colloidal stability in physiological conditions and (2) the in vitro investigation of the biological behavior of two types of drug nanocarriers: chitosan-iron based nanogels and polydiacetylene micelles
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Hachet, Emilie. "Systèmes biocompatibles et biodégradables par modification chimique contrôlée de polysaccharides pour le traitement de patients diabétiques." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENV083.
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Ce travail de thèse s'inscrit dans un domaine de recherche actuellement en pleine expansion, celui des nanomatériaux stimulables. Il vise à concevoir de nouveaux matériaux biocompatibles et biodégradables par modification chimique contrôlée de polysaccharides pour le traitement de patients diabétiques. Le diabète est un problème de santé publique majeur qui affecte environ 250 millions de personnes dans le monde actuellement contre 30 millions il y a 20 ans. Cette maladie se traduit par un taux de glucose anormalement élevé dans le sang dû à un manque d'insuline. Cette protéine est habituellement injectée de manière sous-cutanée, 2 à 4 fois par jour. Les hydrogels/nanogels visés dans ce travail doivent donc être capables de libérer l'insuline en fonction du taux de glucose dans le sang. Ce projet comporte plusieurs volets : (i) la synthèse contrôlée de polysaccharides porteurs de groupements permettant la réticulation des polymères ainsi que des molécules sensibles au glucose , (ii) la synthèse et la caractérisation d'hydrogels et nanogels (en utilisant des liposomes comme nanoréacteurs)<br>This PhD thesis belongs to the area of stimuli-responsive materials, which have attracted a growing interest since several years. Its aim is to design biocompatible and biodegradable stimuli-responsive nanogels obtained from chemically modified polysaccharides to treat diabetic patients. These systems may be used to release insulin in a self-regulated manner. This common disorder of blood glucose regulation due to a lack of insulin is a major public health problem affecting about 250 millions of people in the world today, as compared to 30 millions twenty years ago. Patients diagnosed with insulin-dependent diabetes must take insulin by injecting themselves with a needle at least twice a day. The nanogels targeted in this work are thus expected to release insulin as a function of blood glucose concentration.This project will thus consist in the controlled synthesis of polysaccharides bearing cross-linkable groups and a sugar sensor. These biopolymers will be then used to prepare hydrogels and nanogels (using liposomes as nanoreactors)
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Kawasaki, Riku. "Development of Organic-Inorganic Hybrid Polysaccharide Nanogels for Drug Delivery Nanocarriers." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225632.
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Denmark, Daniel Jonwal. "Photopolymerization Synthesis of Magnetic Nanoparticle Embedded Nanogels for Targeted Biotherapeutic Delivery." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6827.
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Conventional therapeutic techniques treat the patient by delivering a biotherapeutic to the entire body rather than the target tissue. In the case of chemotherapy, the biotherapeutic is a drug that kills healthy and diseased cells indiscriminately which can lead to undesirable side effects. With targeted delivery, biotherapeutics can be delivered directly to the diseased tissue significantly reducing exposure to otherwise healthy tissue. Typical composite delivery devices are minimally composed of a stimuli responsive polymer, such as poly(N-isopropylacrylamide), allowing for triggered release when heated beyond approximately 32 °C, and magnetic nanoparticles which enable targeting as well as provide a mechanism for stimulus upon alternating magnetic field heating. Although more traditional methods, such as emulsion polymerization, have been used to realize these composite devices, the synthesis is problematic. Poisonous surfactants that are necessary to prevent agglomeration must be removed from the finished polymer, increasing the time and cost of the process. This study seeks to further explore non-toxic, biocompatible, non-residual, photochemical methods of creating stimuli responsive nanogels to advance the targeted biotherapeutic delivery field. Ultraviolet photopolymerization promises to be more efficient, while ensuring safety by using only biocompatible substances. The reactants selected for nanogel fabrication were N-isopropylacrylamide as monomer, methylene bisacrylamide as cross-linker, and Irgacure 2959 as ultraviolet photo-initiator. The superparamagnetic nanoparticles for encapsulation were approximately 10 nm in diameter and composed of magnetite to enable remote delivery and enhanced triggered release properties. Early investigations into the interactions of the polymer and nanoparticles employ a pioneering experimental setup, which allows for coincident turbidimetry and alternating magnetic field heating of an aqueous solution containing both materials. Herein, a low-cost, scalable, and rapid, custom ultraviolet photo-reactor with in-situ, spectroscopic monitoring system is used to observe the synthesis as the sample undergoes photopolymerization. This method also allows in-situ encapsulation of the magnetic nanoparticles simplifying the process. Size characterization of the resulting nanogels was performed by Transmission Electron Microscopy revealing size-tunable nanogel spheres between 50 and 800 nm by varying the ratio and concentration of the reactants. Nano-Tracking Analysis indicates that the nanogels exhibit minimal agglomeration as well as provides a temperature-dependent particle size distribution. Optical characterization utilized Fourier Transform Infrared and Ultraviolet Spectroscopy to confirm successful polymerization. When samples of the nanogels encapsulating magnetic nanoparticles were subjected to an alternating magnetic field a temperature increase was observed indicating that triggered release is possible. Furthermore, a model, based on linear response theory that innovatively utilizes size distribution data, is presented to explain alternating magnetic field heating results. The results presented here will advance targeted biotherapeutic delivery and have a wide range of applications in medical sciences like oncology, gene delivery, cardiology and endocrinology.
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Hildebrandt, Haika Verfasser], Martin [Akademischer Betreuer] [Möller, and Jürgen [Akademischer Betreuer] Groll. "Multifunctional nanogels for biomedical applications / Haika Hildebrandt ; Martin Möller, Jürgen Groll." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1181335221/34.
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Hildebrandt, Haika [Verfasser], Martin [Akademischer Betreuer] Möller, and Jürgen [Akademischer Betreuer] Groll. "Multifunctional nanogels for biomedical applications / Haika Hildebrandt ; Martin Möller, Jürgen Groll." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1181335221/34.
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Poirot, Robin. "Design of polysaccharide-based nanogels for the controlled release of insulin." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAV089.
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La prise en charge du diabète de type I se fait à l’heure actuelle par des injections pluriquotidiennes d’insuline ou par l’utilisation d’une pompe à insuline qui va mimer l’activité pancréatique. Dans ce contexte, les nanogels sensibles au glucose représentent des candidats à fort potentiel pour une délivrance contrôlée de l’insuline.La majorité des matériaux développés à ce jour ne présentent pas d’études en vue d’application in vivo et ce, pour diverses raisons telles que la non validation du caractère biocompatible et biorésorbable de la matrice polymère. Afin de répondre à ces deux critères, nous avons choisi de développer des nanogels à base de polysaccharides biocompatibles et biodégradables.Des travaux antérieurs au sein du laboratoire ont porté sur la conception d’hydrogels à base d’acide hyaluronique. Le polysaccharide a été fonctionnalisé avec des dérivés de l’acide phénylboronique (PBA) et du maltose. Ces modifications permettent dans des conditions physiologiques de générer des réticulations boronate-ester. Ces liaisons permettent d’induire une modification de la structure des hydrogels en réponse à divers stimuli tel que le pH ou l’addition de composés saccharidiques.Afin de faciliter l’administration de tels matériaux, nous avons étendu ce concept à la formation de nanogels. Des nanogels sensibles au pH et/ou à l’addition de saccharides ont pu être obtenus en conditions physiologiques grâce au choix judicieux des polysaccharides partenaires modifiés par le PBA et des molécules portant des fonctions diol. Ces nanogels sont capables de piéger l’insuline lors de leur formation avec une efficacité d’encapsulation allant de 45% à 80% et une capacité d’encapsulation de 10% à 60%. Les premiers tests ont montré un faible relargage de l’insulin par nos nanogels.Finalement, au vue de la sensibilité au pH de nos nanogels et l’environnement acide présent autour des tumeurs, leur utilisation pour le traitement du cancer a été étudié. Des analyses in vitro ont démontré une faible toxicité de nos gels sur les cellules cancéreuses. Les premières expériences in vivo ont montré la capacité des nanogels à circuler dans le sang<br>Type 1 diabetes management is currently done by multiple insulin injections or by the use of an insulin pump that will mimic pancreatic activity. In this context, glucose-sensitive nanogels represent high potential candidates for controlled delivery of insulin.The majority of materials developed so far are limited to biological in vitro studies, which is partly due to the non-biocompatibility and limited biodegradability of polymers used for the preparation of such materials. To fulfill these criteria, we proposed to develop nanogels based on biocompatible and biodegradable polysaccharides.Previous work in our laboratory focused on the design of boronate-crosslinked hydrogels based on hyaluronic acid. This polysaccharide was functionalized with derivatives of phenylboronic acid (PBA) and of maltose. The dynamic covalent boronate ester crosslinks between the polysaccharide chains enabled to induce a structural change of the hydrogel in response to various stimuli such as pH or addition of carbohydrate molecules.In order to facilitate administration of such materials, we extended the concept to the formation of nanogels. Sugar- and pH-sensitive nanogels could be successfully obtained in physiological conditions thanks to the judicious choice of the polysaccharide partners, bearing PBA moieties and diol-containing molecules.These nanogels can entrap insulin during their formation with an entrapment efficiency of 45% to 80% and a loading capacity ranging from 10% to 60%. Preliminary experiments indicated a low release of insulin from the nanogels.Finally, in view of the pH-sensitivity of these nanogels and the slight acidic pH of the tumor environment, we investigated their potential application for the treatment of cancer. In vitro experiment demonstrated a low toxicity of our nanogels on cancer cells. Preliminary in vivo experiments indicated that the nanogels can circulate in the bloodstream
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Guerry, Alexandre. "Copolymères à base de polycaprolactones greffées par des chitooligosaccharides : vers des nanogels bioactifs et biostimulables." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00848249.
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Actuellement, la mise au point de systèmes de vectorisation d'agents chimio-thérapeutiques performants fait l'objet d'une intense recherche. Les nanoparticules en particulier sont étudiées, car elles permettent de solubiliser des molécules hydrophobes en milieux aqueux tout en diminuant leur toxicité et leur dégradation. Toutefois, le devenir à long terme des nanoparticules est un paramètre important qu'il faut considérer dans la conception de ces nanovecteurs. Pour cette raison, le développement de nanoparticules auto-assemblées constituées de copolymères à bloc entièrement biocompatibles, biodégradables et aux propriétés de libération contrôlée est recommandé. Dans cette perspective, nous avons étudié les propriétés d'auto-organisation de copolymères greffés amphiphiles de type chitooligosaccharide-grafted-polycaprolactone. Le premier chapitre révèle l'utilisation de l'aniline et de son dérivé alcyne comme un outil efficace pour l'amination réductrice de chitooligosaccharides. Dans le second chapitre, différentes familles de polycaprolactone avec des fonctions azide latérales sont décrites. Le troisième chapitre traite du couplage par chimie " click " de chaque bloc ainsi que de la caractérisation physico-chimique des nanoparticules en solution aqueuse. La réticulation de ses particules a permis d'obtenir les nanogels finaux. Pour conclure, des tests d'encapsulation et de libération contrôlée de la Doxorubicine (avec ou sans ajout de glutathion) ont été effectués
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Torres, Martínez Ana. "Molecular nanogels as nanocarriers. Intracellular transport of photosensitizers and nitric oxide probes." Doctoral thesis, Universitat Jaume I, 2021. http://hdl.handle.net/10803/671255.
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The preparation of molecular nanogels is reported in this thesis. These new nanoparticles, formed by low molecular weight gelators, represent an exciting alternative to their polymeric counterparts considering their intrinsic characteristics (fully reversible stimuli-regulated assembly, easy biodegradation, excellent biocompatibility and tailored properties). Novel hydrogel@liposome particles were also obtained by molecular gel formation inside liposomes, merging the benefits of liposomal vehicles with the inherent characteristics of molecular gels. The capability of molecular nanogels to incorporate and release actives and act as intracellular carriers was demonstrated, improving the efficiency of photoactive molecules in their biomedical use. Photosensitizers (Rose Bengal and hypericin) showed enhanced cellular uptake and improved performance in photodynamic therapy for cancer. The encapsulation in the nanogels of nitric oxide probes lead to an enhanced cellular uptake of DAF-2 and an increased solubility in water of DAQ.<br>En esta tesis se describe la preparación de nanogeles moleculares. Estas nuevas nanopartículas, formadas por gelantes de bajo peso molecular, son una alternativa a sus homólogos poliméricos por sus características intrínsecas (ensamblado completamente reversible y regulado por estímulos, fácil biodegradación, excelente biocompatibilidad y propiedades a medida). También se obtuvieron nuevos lipogeles moleculares formando un gel molecular dentro de un liposoma, lo que combina los beneficios de los liposomas como vehículos con las características inherentes de los geles moleculares. Se demostró la capacidad de los nanogeles moleculares para actuar como portadores intracelulares, mejorando la eficiencia de moléculas fotoactivas en su uso biomédico. Así, los fotosensibilizadores (Rosa de Bengala e hipericina) mostraron una mejora en la internalización celular y el rendimiento en terapia fotodinámica, mientras que para las sondas de óxido nítrico se vio una mayor internalización celular para DAF-2 y una mejora de la solubilidad para DAQ.
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Singh, Neetu. "Synthetic routes to new core/shell nanogels design and application in biomaterials /." Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/28261.
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A very interesting class of nanoparticles extensively used for bio-applications is that of hydrogel particles, also called nanogels. There is an increasing interest in the design of hydrogel nanoparticles that have biofunctionality for applications in cell targeting, drug delivery, and biomedicine. The dissertation focuses on developing synthetic strategies for making diverse hydrogel nanoparticles customized to have desirable properties for various bio-applications. We have also investigated the potential of such nanoparticles as coatings for biomedical implants. Chapter 1 gives a brief introduction to hydrogel nanoparticles and the properties that make them attractive for various applications. The details of the syntheses of well defined, stable nanoparticles, commonly used in literature, are described in Chapter 2. Chapter 3 describes our synthesis of hollow sub-50 nm nanogels, which are otherwise difficult to synthesize based on the strategy discussed in Chapter 2. Chapter 4 also demonstrates how simple strategies borrowed from organic chemistry help in producing nanogels with multiple functionalities that are otherwise difficult to obtain, which also is an important advance over the synthetic methods discussed in Chapter 2. Chapter 5 describes how a general strategy based on photoaffinity labeling can yield materials with many applications ranging from optical materials, drug delivery, to biosensing. The latter part of the dissertation describes applications of various nanogels in biology especially as coatings that can control inflammation caused by biomaterials. Chapter 6 describes a method to functionalize flexible biomaterials with the nanogels, thus enabling in vivo investigations of the nanogels as potential coatings for controlling inflammation. Chapter 7 describes the biological studies performed (in collaboration with Garcia Group in the School of Mechanical Engineering at Georgia Tech) on various nanogels, aimed towards obtaining the most functional and efficient materials for implant applications. Chapter 8 describes application of hollow nanogels for covalently immobilizing biomolecules. This chapter also demonstrates how simple non-functional materials can be made unique and functional by means of traditional organic reactions. Finally, in order to broaden the applications of nanogel based materials.
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Singh, Smriti [Verfasser]. "Biocompatible and biodegradable nanogels and hydrogels for protein/peptide delivery / Smriti Singh." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2014. http://d-nb.info/1058392042/34.
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Chianello, Giorgio. "Methacrylate based nanogels as drug delivery system and Pickering-Ramsden emulsion stabiliser." Thesis, Queen Mary, University of London, 2016. http://qmro.qmul.ac.uk/xmlui/handle/123456789/24565.
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A novel methacrylate based nanogel system has been designed and developed for drug delivery applications. Methacrylates are optimal tuneable materials in terms of polarity, with combination of hydrophobic and hydrophilic moieties. Synthesis of these nanogels (NGs) was achieved via high dilution radical polymerisation using 2-(tert-butylamino)ethyl methacrylate (tBAEMA) as functional monomer, methacrylic acid (MAA) or ethylene glycol methyl ether methacrylate (EGMMA) as co-monomer and N,N'-methylenebis(acrylamide) (MBA) as cross-linker. Fabricated nanoparticles (NPs) were shown to possess water solubility higher than 2 mg/mL and diameter ranging from 5 to 20 nm (depending on nanogels' composition) as confirmed by either dynamic light scattering (DLS) and transmission electron microscopy (TEM). Moreover, nanogels produced have shown the ability to be employed as Pickering-Ramsden emulsion stabiliser. Their reduced size together with their emulsion capabilities make these nanoparticles a promising system for drug delivery, in particular taking into account skin as administration route. The size is in fact small enough to favour their penetration through the stratum corneum. Furthermore, in the view of their ability to form emulsions, nanogels could be used both as drug carrier and emulsifier in a final pharmaceutical formulation. NGs proved to be able to incorporate both small molecule such as fenoprofen (an anti-inflammatory non-steroidal drug) and big macromolecule such as siRNA. Cytotoxicity and cell metabolism were also evaluated by transfecting normal human dermal fibroblasts (NHDF), keratinocytes (HaCaT) and HeLa cells with nanogels. Data showed that nanoparticles did not affect viability, cells' morphology and adenosine triphosphate (ATP) levels up to high concentration of 100 μg/mL. In addition, preliminary studies indicated the ability of the nanogels to internalise and release their payload inside cells. In conclusion, the results confirmed that this novel system possesses all the desired characteristics to be used as a promising platform for drug delivery.
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Carboni, Davide. "Synthesis and characterisation of novel molecularly imprinted nanogels with aldolase Type I activity." Thesis, Queen Mary, University of London, 2009. http://qmro.qmul.ac.uk/xmlui/handle/123456789/135.
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This research project focussed on using the molecular imprinting approach for the synthesis of nanogels capable of catalysing the cross-aldol reaction between 4-nitrobenzaldehyde and acetone. A polymerisable proline derivative was used as the functional monomer to mimic the enamine-based mechanism of aldolase type I enzymes. A 1,3-diketone template, used to create the cavity, was designed to imitate the intermediate of the aldol reaction and was bound to the functional monomer using a reversible covalent interaction prior to polymerisation. Soluble imprinted nanogels were prepared by using a high-dilution radical polymerisation, which was followed by template removal and estimation of active site concentrations by monitoring the release of 4-nitrophenolate due to the acetylation of proline units with 4-nitrophenyl acetate. Analysis by DLS and TEM confirmed an average particle size of 20 nm for the nanogel preparations, comparable to the size of natural enzymes, and an average molecular mass ranging from 258 to 288 kDa, as determined by GPLC using polymethylmethacrylate standards. The polymers were found to be soluble in DMF, DMSO and mixtures thereof, giving rise to homogeneous solutions. The kinetic characterisation of both imprinted and non-imprinted nanogels was carried out with catalyst concentrations between 0.7 and 3.5% mol. Imprinted nanogel MIP-AS147 was found to have a kcat value of 0.26 × 10-2 min-1, the highest value ever achieved with imprinted nanogels catalysing C-C bond formation. Comparison of the catalytic constants for both imprinted nanogel MIP-AS147 and non-imprinted nanogel NIP-AS133 gave a ratio of kcatMIP /kcatNIP = 20, which is indicative of good imprinting efficiency and highlights the significance of the template during the imprinting process. Analysis of the stereoselectivity of the reaction catalysed by nanogels gave 62% ee, which is comparable with the one of the “free” catalyst. This work is the first and so far only example of imprinted polymer capable of catalysing the cross-aldol addition. The kinetic data obtained provide additional evidence to the hypothesis that the nanogel format is superior to ‘bulk’ polymers for the generation of enzymelike catalysts.
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Zhang, Xuejiao [Verfasser]. "Dendritic Polyglycerol-Based Degradable Nanogels for Transport and Delivery of Bioactive Molecules / Xuejiao Zhang." Berlin : Freie Universität Berlin, 2015. http://d-nb.info/1074404807/34.
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Jorge, Ana Rita. "Molecularity imprinted nanogels as catalysts for phosphate hydrolysis : an approach based on cobalt-cyclem monomers." Thesis, Queen Mary, University of London, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.538660.
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Giulbudagian, Michael [Verfasser]. "Development and Adaptation of Thermoresponsive Nanogels for the Treatment of Inflammatory Skin Diseases / Michael Giulbudagian." Berlin : Freie Universität Berlin, 2018. http://d-nb.info/1150238054/34.
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Smith, Michael Hughes. "The design of multifunctional hydrogel nanoparticles for drug delivery." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43609.
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Hydrogel micro- and nanoparticles (microgels and nanogels) are a promising class of drug delivery vehicles. Composed of hydrophilic polymers arranged into a cross-linked network structure, nanogels show several attractive features for the delivery of macromolecule therapeutics. For instance, the hydrated, porous internal cavity of the nanogel may serve as a high capacity compartment for loading macromolecules, whereas the periphery of the nanogel may be used as a scaffold for conjugating cell-specific targeting moieties. This dissertation presents recent investigations of nanogels as targeted delivery vehicles for oligonucleotides to cancer cells, while exploring new nanogel chemistries that enable future in vivo applications. For instance, synthetic efforts have produced particles capable of erosion into low molar mass constituents, providing a possible mechanism of particle clearance after repeated administration in vivo. In another example, the microgel network chemistry was tuned to promote the encapsulation of charged proteins. In parallel with those synthetic efforts, new light scattering methodologies were developed to accurately quantify the particle behaviors (e.g. loading, erosion). Using multiangle light scattering (MALS), changes in particle molar mass and radius were measured, providing a quantitative and direct approach for monitoring nanogel erosion and macromolecule encapsulation. The new particle chemistries demonstrated, together with enabling light scattering methods, will catalyze the development of improved delivery vehicles in the near future.
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Asadian, Birjand Mazdak [Verfasser]. "Stimuli-responsive Nanogels for Dermatology, Photothermal Therapy, and Detection of Circulating Tumor Cells / Mazdak Asadian Birjand." Berlin : Freie Universität Berlin, 2016. http://d-nb.info/1105472329/34.
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Poly, Julien. "Copolymérisation radicalaire réticulante contrôlée : application à la synthèse de nanogels en présence de xanthates et modélisation." Thesis, Bordeaux 1, 2008. http://www.theses.fr/2008BOR13650/document.
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Les nanogels sont des macromolécules ramifiées solubles possédant une structure en réseau et de dimensions inférieures à 100 nm. La méthodologie récente de la copolymérisation radicalaire réticulante contrôlée permet d'accéder à de telles architectures polymères tout en contrôlant finement leur structure interne. Nous présentons dans ce travail: (i) l'étude préalable de systèmes modèles, permettant de dégager les conditions nécessaires à la synthèse de nanogels; (ii) l'application à la synthèse de nanogels hydrophiles valorisables de poly(alcool vinylique) et de poly(N-vinylpyrrolidone); (iii) une modélisation cinétique permettant de rendre compte des tendances observées expérimentalement et de prévoir les grandeurs caractéristiques de produits synthétisés par cette méthodologie<br>Abstract
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Mendoume-Nze, Jeanne Stella Billon Aurélie. "Les hydrogels et les nanogels des formes galéniques innovantes pour une libération ciblée des principes actifs /." [S.l.] : [s.n.], 2008. http://castore.univ-nantes.fr/castore/GetOAIRef?idDoc=47851.
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Goetz, Lee Ann. "Preparation and analysis of crosslinked lignocellulosic fibers and cellulose nanowhiskers with poly(methyl-vinyl ether co maleic acid) â " polyethylene glycol to create novel water absorbing materials." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45893.
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The search for cellulosic based products as a viable alternative for petroleum-based products was the impetus for covalently crosslinking lignocellulosic fibers and nanocellulose whiskers with poly(methyl vinyl ether) co maleic acid (PMVEMA) - polyethylene glycol (PEG). The lignocellulosics used were ECF bleached softwood (pine) and ECF bleached birch kraft pulp. This thesis also tests the hypothesis that water absorption and retention can be improved by grafting PMVEMA-PEG to the surface of ECF bleached kraft pulp hardwood and softwood fibers via microwave initiated crosslinking. The crosslinking of the PMVEMA to hardwood and softwood kraft ECF bleached pulp fibers resulted in enhanced water absorbing pulp fibers where the PMVEMA is grafted onto the surface of the fibers. The crosslinking was initiated both thermally and via microwave irradiation and the water absorption and water retention was measured as the percent of grafted PMVEMA. This was the first application of microwave crosslinking of pulp fibers with the goal of creating water absorbing pulp fibers. Ultimately, the water absorption values ranged from 28.70 g water per g dry crosslinked pulp fiber (g/g) to 230.10 g/g and the water retention values ranged from 26% to 71% of the water retained that was absorbed by the crosslinked pulp fibers. The microwave initiated crosslinked fibers had comparable results to the thermally crosslinked fibers with a decreased reaction time, from 6.50 min (thermal) to 1 min 45 sec (microwave).
Cellulose nanowhiskers, crystalline rods of cellulose, have been investigated due to their unique properties, such as nanoscale dimensions, low density, high surface area, mechanical strength, and surface morphology and available surface chemistry. Prior to this study, the crosslinking of cellulose whiskers with the matrix via solution casting of liquid suspensions of whiskers and matrix had not been explored. The hypothesis to be investigated was that incorporating cellulosic whiskers with the PMVEMA-PEG matrix and crosslinking the whiskers with the matrix would yield films that demonstrate unique properties when compared to prior work of crosslinking of PMVEMA-PEG to macroscopic ECF bleached kraft pulp fibers.
Solution cast composites of cellulose nanowhiskers-PMVEMA-PEG were crosslinked at 135 °C for 6.5 min and analyzed for crosslinking, thermal stability, strength and mechanical properties, whisker dispersion, and water absorption and uptake rates. The whisker-composites demonstrated unique properties upon crosslinking the whiskers with PMVEMA-PEG, especially the elongation at break and tensile strength upon conditioning of the final materials at various relative humidities. In addition, the whiskers improved the thermal stability of the PMVEMA-PEG matrix. This is significant as methods of improving processing thermal stability are key to developing new materials that utilize cellulose whiskers, PMVEMA, and PEG. This thesis addresses the hypothesis that cellulose nanowhiskers that are crosslinked with a matrix can create new whisker-matrix composites that behave differently after crosslinking.
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Abed, Aïcha. "Nouveaux dispositifs médicaux à base d'hydrogels de polysaccharides." Paris 13, 2012. http://www.theses.fr/2012PA132062.
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Les travaux décrits dans ce mémoire sont consacrés à la mise au point de nouveaux dispositifs médicaux à base d’hydrogels de polysaccharides (pullulane et dextrane). Depuis quelques années, notre laboratoire s’intéresse aux propriétés biologiques de polysaccharides synthétiques ou naturels et à leur rôle comme agents de cicatrisation via les interactions avec les facteurs de croissances endogènes et les composants matriciels. Nous avons donc eu l’idée d’appliquer leurs propriétés à la conception d’un matériau hybride composé d’un treillis de polypropylène recouvert d’hydrogel de polysaccharides. Le premier objectif de ce travail de thèse vise à améliorer l’intégration de matériaux utilisés actuellement en clinique en proposant une prothèse hybride et à mieux comprendre les propriétés de ces hydrogels tant in vitro qu’in vivo pour ajuster au mieux les applications et le développent possible de ces matériaux. Dans la deuxième partie de ce travail, en se basant sur les propriétés des hydrogels un nouveau système de conservation et de transport de tissu à température ambiante a été mis au point tout en limitant les chocs mécaniques et les contaminations liés aux fuites liquidiennes. En prenant comme modèle les artères de rat, nous avons validé ce dispositif in vitro et in vivo. Enfin, nous avons développé un nouveau système de cryoconservation des cellules et tissus. Ce système à base d’hydrogel permet de diminuer les quantités d’agents cryoprotectants toxiques lors de la congélation. Cette méthode a été validée in vitro etcomparée à la procédure de référence<br>This work describes the development of new medical devices based on hydrogel of polysaccharides (pullulan and dextran). In recent years, our laboratory was interested in the biological properties of synthetic or natural polysaccharides and their interactions with endogenous growth factors and matrix components. So we had the idea to apply their properties to the design of a hybrid material composed of a polypropylene mesh coated with polysaccharides hydrogel. The first objective of this work is to improve the integration of materials currently used in clinical by using of hybrid prosthesis and understand the properties of these hydrogels in vitro and in vivo. In the second part of this work, based on the hydrogel properties a new system of storage and transport of tissue at room temperature was developed while limiting mechanical shocks and contamination associated with leaking fluids. Taking as a model of rat arteries, we validated this system in vitro and in vivo. Finally, we developed a new system for cryopreservation of cells and tissues. This hydrogel based polysaccharides reduces the quantities of toxic cryoprotectants agents during freezing. This method was validated in vitro and in vivo and in comparison with the reference procedure
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Bobb, Julian A. "LASER SYNTHESIS OF NANOMATERIALS INCORPORATED WITHIN HIGH SURFACE AREA MATERIALS: APPLICATIONS FOR HETEROGENEOUS CATALYSIS, WATER TREATMENT, AND PHOTOTHERMAL ENERGY CONVERSION." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5693.
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Chemical methods are generally used for the synthesis of active nanoparticles (metals, semi-metals, metal oxides, and etc) supported on high surface area materials. Chemical methods involve using strong solvents, harmful gases (H2 & CO), and high temperature techniques such as high boiling solvents, calcination and pyrolysis. The main drawbacks of using this approach, is the prevalence of chemical agents on nanomaterials which tends to negate its applications. Alternatively, photochemical and photothermal methods are widely being considered for the synthesis and design of nanomaterials.
For these studies, the active nanomaterials incorporated within high surface area materials were prepared by the laser vaporization-controlled condensation (LVCC) technique or by the laser irradiation in solution (LIS) technique. The LVCC technique involves the irradiation of a solid target at the focal point of a laser beam (532 nm, 30 Hz) by the Nd: YAG laser inside a chamber that is sandwiched between two steel plates in the presence of high purity He. Whereas, the LIS technique involves the laser irradiation of chemical precursors in aqueous solvents using an unfocused beam. The LVCC technique was used for the preparation of carbonaceous and N-doped carbonaceous TiO2 support materials from MIL-125(Ti) and NH2-MIL-125(Ti) metal organic frameworks, Ge and GeO2 nanostructures, GeOx/PRGO nanocomposite, and the Fe3O4/PRGO nanocomposite. On the other hand, Pd supported on MIL-125(Ti) and NH2-MIL-125(Ti) nanocatalysts, GeO2/RGO, and the poly(ethylene glycol methacrylate-co-bisacrylamide) hydrogels were all prepared by the LIS technique.
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Chevalier-Menu, Aurélia. "Comment concevoir un protocole d'application des technologies laser et nanogels pour la conservation/restauration des peintures sur toile." Phd thesis, Ecole nationale supérieure d'arts et métiers - ENSAM, 2010. http://pastel.archives-ouvertes.fr/pastel-00563478.
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La recherche en conservation justifie et nécessite la mise en commun de compétences différentes et complémentaires. Un protocole innovant intégrant les lasers et les nanogels a été élaboré pour la conservation-restauration d'œuvres peintes sur toile. Cette recherche s'appuie sur l'expertise de chimistes, de physiciens associés aux historiens d'art et aux restaurateurs. Une telle démarche bouleverse à terme les pratiques des restaurateurs et engage la profession dans une nouvelle perspective de modèle industriel. C'est pourquoi, l'apport du LCPI de l'ENSAM fut déterminant pour proposer une méthode d'intégration des technologies innovantes à un métier caractérisé jusqu'alors par une tradition ancestrale de transmission de techniques héritées des pratiques artistiques. Le mémoire s'articule en cinq parties qui abordent les différents aspects de la problématique de recherche. Dans un premier temps, une recherche documentaire fait le constat de l'état du métier de restaurateur de peintures, en décrivant au fil des siècles comment tout d'abord se sont constituées les collections nationales avec une conscience de l'émergence d'un patrimoine collectif. Concomitamment et naturellement des questions de conservation-restauration se sont alors posées, à l'origine même du métier de restaurateur. Dans une seconde partie, la problématique de la thèse est décrite, aboutissement d'une réflexion sur les moyens traditionnels pour dégager les adhésifs de rentoilage. L'hypothèse fut énoncée que les lasers et les nanogels devraient pouvoir remplacer à terme les méthodes mécaniques (scalpel) et chimiques (gels classiques). La troisième partie s'attelle donc à mettre en place le modèle méthodologique, définir un plan d'expériences s'appuyant sur une connaissance des interactions laser-matière et des effets des gels chimiques sur les différents adhésifs testés. La quatrième partie présente alors les résultats des expérimentations et propose une interprétation dont on cherche la validation par diverses méthodes comme l'interférométrie holographique. La cinquième partie est un essai de synthèse de la recherche et propose une méthodologie nouvelle basée sur un modèle scientifique pour parfaire l'élimination des adhésifs des supports-toile. Au sein d'une démarche " métiers ", la méthode intègre les différents paramètres et les différentes contraintes de la pratique des restaurateurs pour concevoir une approche nouvelle en mettant en œuvre des procédés innovants. Une telle recherche doit aboutir à la mise en place d'un protocole contrôlé et reproductible, basé sur une automatisation mettant en œuvre la réalité augmentée. Cette méthodologie soucieuse de l'environnement et du développement durable ne néglige pas l'expérience de l'œil des praticiens
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Gupta, Prachi. "SYNTHESIS AND CHARACTERIZATION OF ANTIOXIDANT CONJUGATED POLY(ΒETA-AMINO ESTER) MICRO/NANOGELS FOR THE SUPPRESSION OF OXIDATIVE STRESS". UKnowledge, 2016. http://uknowledge.uky.edu/cme_etds/58.
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Oxidative stress is a pathophysiological condition defined by an increased production of reactive oxygen species (ROS), which can result in the growth arrest of cells followed by cell disintegration or necrosis. A number of small molecule antioxidants (e.g. curcumin, quercetin and resveratrol) are capable of directly scavenging ROS, thereby short-circuiting the self-propagating oxidative stress state. However, poor solubility and rapid 1st pass metabolism results in overall low bioavailability and acts as a barrier for its use as a drug to suppress oxidative stress efficiently.
To overcome this limitation, these small molecule antioxidants were covalently conjugated into poly(β-amino ester) (PβAE) cross-linked networks to formulate prodrug gel microparticles and nanoparticles (nanogels). Being hydrolytically degradable in nature, these PβAE crosslinked systems released antioxidants in their original structural form in a sustained controlled fashion.
Both quercetin and curcumin-PβAE nanogels showed prolonged suppression of cellular oxidative stress induced by H2O2. Curcumin PβAE nanogels also demonstrated protection against mitochondrial oxidative stress induced by H2O2 and polychlorinated biphenyls.
Curcumin-PβAE gel microparticles were also developed as a platform to treat oral mucositis through a local antioxidant delivery route. The same synthesis chemistry was transferred to formulate resveratrol PβAE gel microparticles for topical applications, to treat UV radiation induced oxidative stress. Both formulations showed suppression of induced oxidative stress. An in vivo trial with curcumin-PβAE microparticles further showed relatively reduced the severity of induced oral mucositis (OM) in hamster check pouch as compared to placebo.
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Chevalier, Aurélia. "Comment concevoir un protocole d'application des technologies laser et nanogels pour la conservation/restauration des peintures sur toile." Paris, ENSAM, 2010. http://www.theses.fr/2010ENAM0035.
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La recherche en conservation justifie et nécessite la mise en commun de compétences différentes et complémentaires. Un protocole innovant intégrant les lasers et les nanogels a été élaboré pour la conservation-restauration d'œuvres peintes sur toile. Cette recherche s'appuie sur l'expertise de chimistes, de physiciens associés aux historiens d'art et aux restaurateurs. Une telle démarche bouleverse à terme les pratiques des restaurateurs et engage la profession dans une nouvelle perspective de modèle industriel. C'est pourquoi, l'apport du LCPI de l'ENSAM fut déterminant pour proposer une méthode d'intégration des technologies innovantes à un métier caractérisé jusqu'alors par une tradition ancestrale de transmission de techniques héritées des pratiques artistiques. Le mémoire s'articule en cinq parties qui abordent les différents aspects de la problématique de recherche. Dans un premier temps, une recherche documentaire fait le constat de l'état du métier de restaurateur de peintures, en décrivant au fil des siècles comment tout d'abord se sont constituées les collections nationales avec une conscience de l'émergence d'un patrimoine collectif. Concomitamment et naturellement des questions de conservation-restauration se sont alors posées, à l'origine même du métier de restaurateur. Dans une seconde partie, la problématique de la thèse est décrite, aboutissement d'une réflexion sur les moyens traditionnels pour dégager les adhésifs de rentoilage. L'hypothèse fut énoncée que les lasers et les nanogels devraient pouvoir remplacer à terme les méthodes mécaniques (scalpel) et chimiques (gels classiques). La troisième partie s'attelle donc à mettre en place le modèle méthodologique, définir un plan d'expériences s'appuyant sur une connaissance des interactions laser-matière et des effets des gels chimiques sur les différents adhésifs testés. La quatrième partie présente alors les résultats des expérimentations et propose une interprétation dont on cherche la validation par diverses méthodes comme l'interférométrie holographique. La cinquième partie est un essai de synthèse de la recherche et propose une méthodologie nouvelle basée sur un modèle scientifique pour parfaire l'élimination des adhésifs des supports-toile. Au sein d'une démarche « métiers », la méthode intègre les différents paramètres et les différentes contraintes de la pratique des restaurateurs pour concevoir une approche nouvelle en mettant en œuvre des procédés innovants. Une telle recherche doit aboutir à la mise en place d'un protocole contrôlé et reproductible, basé sur une automatisation mettant en œuvre la réalité augmentée. Cette méthodologie soucieuse de l'environnement et du développement durable ne néglige pas l'expérience de l'œil des praticiens<br>The research in conservation needs to bring together different and complementary expertises. An innovative method integrating lasers and nanogels is proposed for the conservation of easel paintings. This research takes advantage of the scientific approach of chemists and physicists who accepted to work in a collaborative way with art historians, curators and conservators. Such an innovation has paramount consequences in the traditional practice proper of the conservators and the profession may so be foreseen in a new perspective with industrial aspects. That's why the input of the Product Design and Innovation Laboratory (LCPI) of the Ecole Nationale Supérieure des Arts et Métiers (ENSAM) was decisive for achieving an integrated method to a profession which may be characterised by a long term tradition applying techniques derived from artistic practices. The dissertation is divided in five chapters which are characteristic of the problematic of the present research work. In a first step, a synthetic documentation is brought to light to emphasize the traditional practices of the painting conservators, how the French collections emerged after the Renaissance and how the French Cultural heritage was formed. The second chapter described the research problematic, after presenting the questions asked by the classical means to extract the lining adhesives. Lasers and nanogels are then hypothetically proposed to replace in due time the mechanical (scalpel) and chemical (conventional gels) methods. The third chapter is so devoted to the definition of the methodological model, to the proposition of an experimental program able to end the deadlock in the removal of ancient lining products. This program is based on the knowledge of the laser-matter interactions and of the effective action of chemical gels on the various adhesives considered. The fourth chapter presents the experimental results and the interpretation is validated by several methods as holographic interferometry. The fifth and last chapter is the synthesis of our research, describes the innovative methodology based on a scientific model in order to remove the adhesives of ancient linings before any conservation work. This research is achieved inside a “Profession” process which leads to a controlled and reproducible protocol integrating innovative methods. This methodology takes care of the sustainable development, of the environmental considerations and does not forget the experienced eyes of the practitioners
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Bueno, Vânia Aparecida Blasques. "Produção de hidrogéis micro e nanoestruturados." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/46/46135/tde-14102010-142141/.
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Hidrogéis (redes poliméricas tridimensionais capazes de absorver grandes quantidades de água) micro e nanoestruturados têm grande potencial como biomateriais em aplicações tais como dispositivos de liberação de fármacos e agentes embólicos. Neste trabalho foram estudadas técnicas de produção desses hidrogéis micro e nanoestruturados à base de poli(N-vinil-2-pirrolidona) (PVP), a partir da reticulação do polímero através de reações de Fenton, foto-Fenton e fotólise direta. Microgéis de PVP foram obtidos a partir da reticulação de esferas obtidas por eletropulverização ou de gotículas de solução aquosa do polímero em emulsão a/o. No primeiro caso, obtiveram-se partículas que, quando reticuladas com a reação de Fenton durante o processo de eletropulverização, apresentaram formato indefinido. No segundo caso, foram obtidas microesferas de PVP, tanto pela reticulação com a reação de Fenton, obtendo-se partículas menores da - ordem de 1 µm - como com a reação de foto-Fenton, que gerou partículas maiores de - 34 µm. Hidrogéis sub-micrométricos foram obtidos a partir da formatação em vesículas de lecitina e reticulados por meio da reação de foto-Fenton. Essas vesículas foram capazes de encapsular grande quantidade de polímero, mesmo sendo este de alta massa molar média. Os hidrogéis sintetizados apresentam estreita distribuição de diâmetro, porém sem forma definida e com baixo índice de intumescimento. Por fim, nanogéis (nanopartículas de hidrogéis) foram obtidos da reticulação de PVP com a reação de Fenton (Fe2+ na presença de H2O2), utilizando como sistema formatador o interior aquoso de micelas reversas de CTAB. Os nanogéis assim formados são esféricos e apresentam propriedades interessantes, como fator de intumescimento de até 6000, inédito na literatura, que os colocam na categoria de hidrogéis superabsorventes. Além disso, o intumescimento é passível de controle tanto pela remoção dos íons Fe3+ complexados, como pela acidez e composição iônica do meio. Durante o desenvolvimento da síntese dos nanogéis foi possível estudar a influência do Fe3+ na estruturação da solução polimérica e do hidrogel. Além disso, a cinética da reticulação do polímero dentro das micelas e uma comparação entre dois sistemas micelares diferentes na formatação do nanogel foram analisados. A análise do produto também permitiu constatar a baixa toxicidade do material obtido com testes in vitro utilizando macrófagos e fibroblastos.<br>Micro and nanostructured hydrogels (three-dimensional polymeric networks capable of absorbing large amounts of water) have great potential as biomaterials in applications such as drug delivery devices and embolic agents. In this work techniques to produce micro and nanostructured hydrogels from poly(N-vinyl-2-pyrrolidone) (PVP) were studied from various crosslinking reactions like Fenton, photo-Fenton and direct photolysis. PVP microgels were obtained from crosslinking of polymer spheres obtained by electrospraying a polymer solution or from droplets of aqueous polymer solution in w/o emulsion. In the first case, particles were obtained that, when crosslinked with the Fenton reaction, showed undefined morphology. In the second case, spherical PVP hydrogel microparticles were obtained, which were formed by crosslinking with Fenton reaction, resulting in smaller particles - about 1µm - while with photo-Fenton reaction it generated larger particles - about 34 µm. Sub-micrometric hydrogels were obtained from lecithin vesicles as formatting system through crosslinking with photo-Fenton reaction. These vesicles were able to encapsulate large amounts of polymer, in spite of its high average molecular weight. Hydrogels synthesized by this method are formless, with narrow diameter distribution and low swelling properties. Finally, nanogels (hydrogel nanoparticles) were obtained from crosslinking of PVP by the Fenton reaction (Fe2+ in presence of H2O2), using aqueous pool of CTAB reverse micelles as formatting system. The thus formed nanogels are spherical and present interesting properties such as swelling ratio of 6000, a level unreported in literature, which classifies them as superabsorbent hydrogels. Moreover, the swelling is susceptible to control either by the removal of complexed Fe3+ ions or by acidity and ionic composition of the medium. During the nanogels synthesis development, the influence of Fe3+ in the arrangement of the polymer solution and of the hydrogel was studied. Morever, the polymer crosslinking kinetics inside the micelles and a comparison between two different micellar systems in formatting of nanogel were analyzed. The product analysis also revealed low toxicity of the obtained material by in vitro experiments using macrophages and fibroblasts.
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Cázares, Cortés Esther Del Carmen. "Synthèse de nanogels biocompatibles et multi-stimulables pour la libération contrôlée d'une molécule modèle par hyperthermie magnétique et photothermie." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066290/document.
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Les nanogels hybrides constitués de polymères thermosensibles et de nanoparticules inorganiques stimulables telles que des nanoparticules magnétiques (NPMs) ou des nanobatônnets d’or (AuNRs) sont extrêmement intéressants pour des applications biomédicales. Leur matrice en polymère permet d’encapsuler et de libérer de grandes quantités de molécules actives, alors que les nanoparticules peuvent générer de la chaleur lorsqu’elles sont exposées à un champ magnétique alternatif (AMF) pour les NPMs, et à une irradiation proche infrarouge (NIR-L) pour les AuNRs. Ce manuscrit de thèse porte sur la synthèse et la caractérisation de nanogels biocompatibles, pH- et thermosensibles, à base de monomères en oligo (éthylène glycol) méthyl éther méthacrylate (OEGMAs), d’acide méthacrylique (MAA) et encapsulant des NPMs et/ou des AuNRs pour déclencher de manière contrôlée, par hyperthermie magnétique ou par photothermie, la libération d’une molécule anticancéreuse, la doxorubicine (DOX). Des nanogels hybrides magnétiques, plasmoniques et magnéto-plasmoniques ont été synthétisés. Ces nanogels ont un diamètre hydrodynamique entre 200 et 500 nm et une température de transition de phase volumique comprise entre 30 et 54 °C. Le comportement de gonflement-dégonflement des nanogels peut être induit par plusieurs stimuli (température, pH, AMF, NIR-L). Ces résultats démontrent que les MagNanoGels sont d’excellents nanovecteurs pour accroître l’internalisation cellulaire en augmentant la cytotoxicité de la DOX et qu’il est possible de déclencher à distance la libération intracellulaire de DOX sous AMF dans des conditions athermiques. Par ailleurs, les PlasMagNanoGels peuvent générer efficacement de la chaleur par photothermie pour une thermothérapie. En outre, les propriétés intrinsèques des NPMs, pour le ciblage magnétique et en tant qu’agents de contraste pour l’imagerie par résonance magnétique (MRI), font de ces nanogels des candidats idéaux pour une nouvelle approche thérapeutique (diagnostique et traitement) contre le cancer<br>Hybrid nanogels, composed of thermoresponsive polymers and inorganic responsive nanoparticles, such as magnetic nanoparticles (NPMs) and gold nanorods (AuNRs) are highly interesting for biomedical applications. Their polymeric matrix makes them able to uptake and release high quantities of drugs, whereas nanoparticles can generate heat when exposed to an alternating magnetic field (AMF) for NPMs, and to a near-infrared light for AuNRs. This thesis manuscript focuses on the synthesis and the characterization of biocompatible, pH- and thermoresponsive nanogels, based on oligo(ethylene glycol) monomers (OEGMAs), methacrylic acid (MAA) and encapsulating NPMs and/or AuNR for remotely triggered doxorubicin (DOX, anticancer drug) release, by magnetic hyperthermia or phothothermia. Hybrid magnetic, plasmonic and magneto-plasmonic nanogels were synthesized. Theses nanogels have a hydrodynamic diameter between 200 and 500 nm and a volume phase transition temperature (VPTT) from 30 to 54°C. The nanogels’ swelling-deswelling behavior can be induced by several stimuli (temperature, pH, AMF, NIR-L). These results demonstrate that MagNanoGels are excellent nanocarriers for enhancing cellular internalization enhancing DOX cytotoxicity and that DOX release was significantly enhanced upon exposure to AMF in athermic conditions. In addition, PlasMagNanoGels can efficiently generate heat by photothermy for thermotherapy. Therefore, the intrinsic properties of NPMs for magnetic targeting and as contrast agents for Magnetic Resonance Imaging (MRI), make these nanogels ideal candidates for a new therapeutic approach (diagnosis and treatment) against cancer
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Picard, Lionel. "Synthèse et caractérisation de nanoparticules polyuréthane réticulées en solution dans divers milieux de polarité ajustable : applications potentielles des nanogels." Lyon, INSA, 2008. http://theses.insa-lyon.fr/publication/2008ISAL0002/these.pdf.
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Les nanogels polyuréthane sont synthétisés en solution dans des monomères pour trouver des critères gouvernant la nanogélification et la taille des particules. Leur synthèse s’effectue en trois étapes : la formation de prépolymères, leur solubilisation et la réticulation. Les deux premières sont bien connues dans la littérature. La troisième, exploratoire, a permis de synthétiser des nanogels fonctionnalisés ou non, de tailles très faibles en solution concentrée et de comprendre l’influence de nombreux paramètres de synthèse sur la concentration critique de nanogélification C* et sur la taille des nanogels. L’étude rhéologique des solutions de nanogels a permis de comprendre la macrogélification des systèmes et de définir un modèle pour prévoir C*. La polymérisation UV des monomères donnent des PMMA chargés de nanogels ayant des propriétés mécaniques intéressantes. Dans un revêtement PU, les nanogels améliorent l’évaporation du solvant en conservant les propriétés mécaniques du film<br>The polyurethane nanogels are synthesized in solution in monomers to find some criteria that govern the nanogelification and the size of the particles. Their synthesis is performed in three steps: the formation of prepolymers, their solubilization and the cross-linking. Both two first are well known in the literature. The third one, exploratory, allow us to synthesize functionalized (or not) nanogels of very weak sizes in concentrated solution and to understand the influence of many parameters of the synthesis on the critical nanogelation concentration C* and on the nanogels size. The rheological study of the solutions of nanogels enables to understand the macrogelation of the systems and to define a model to predict C*. The UV polymerization of the monomers provides PMMA filled with nanogels, with interesting mechanical properties. In a PU coating, nanogels improve the solvent evaporation while keeping the mechanical properties of the coating
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Drude, Natascha Ingrid [Verfasser], Martin [Akademischer Betreuer] Möller, and Felix M. [Akademischer Betreuer] Mottaghy. "Evaluation of radiolabeled stimuli-sensitive nanogels for application in nuclear medicine / Natascha Ingrid Drude ; Martin Möller, Felix M. Mottaghy." Aachen : Universitätsbibliothek der RWTH Aachen, 2020. http://d-nb.info/1217789375/34.
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Picard, Lionel Mechin Françoise Rousseau Alain. "Synthèse et caractérisation de nanoparticules polyuréthane réticulées en solution dans divers milieux de polarité ajustable applications potentielles des nanogels /." Villeurbanne : Doc'INSA, 2008. http://docinsa.insa-lyon.fr/these/pont.php?id=picard.
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Theune, Loryn Elisabeth [Verfasser]. "Thermo-Responsive Nanogels as Versatile Platform for Smart Drug Delivery Systems and Multi-Functional Photothermal Agents / Loryn Elisabeth Theune." Berlin : Freie Universität Berlin, 2020. http://d-nb.info/1212031814/34.
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Drude, Natascha Ingrid Verfasser], Martin [Akademischer Betreuer] [Möller, and Felix M. [Akademischer Betreuer] Mottaghy. "Evaluation of radiolabeled stimuli-sensitive nanogels for application in nuclear medicine / Natascha Ingrid Drude ; Martin Möller, Felix M. Mottaghy." Aachen : Universitätsbibliothek der RWTH Aachen, 2020. http://d-nb.info/1217789375/34.
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Peng, Huan Verfasser], Andrij Z. [Akademischer Betreuer] [Pich, and Ulrich [Akademischer Betreuer] Schwaneberg. "Reactive stimuli-responsive poly(vinyl lactam) copolymers for design of nanogels based protein and drug carriers / Huan Peng ; Andrij Pich, Ulrich Schwaneberg." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1130402851/34.
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Atanase, Léonard-Ionut. "Contribution à l'étude des complexes Poly (vinyle alcool - vinyle acétate) / tensioactifs anioniques : caractéristiques colloïdales des nanogels et extension aux copolymères à blocs." Phd thesis, Université de Haute Alsace - Mulhouse, 2010. http://tel.archives-ouvertes.fr/tel-00562063.
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Les copolymères poly (acétate de vinyle-co-alcool vinylique), désignés par PVA, sont des tensioactifs macromoléculaires obtenus par hydrolyse partielle de poly (acétate de vinyle)(PVAc). Si les propriétés tensioactives des PVA ont pu être corrélées aux caractéristiques moléculaires il n'en est par de même en ce qui concerne les associats du type nanogels présents dans les solutions aqueuses. L'objectif de cette thèse était de caractériser les nanogels par des techniques telles que la diffusion dynamique de la lumière, la chromatographie d'exclusion stérique et la viscosimétrie. 9 PVA, de degrés d'hydrolyse de 73 à 88 mole% et de degrés de polymérisation de 650 à 2500 ont été étudiés. Il est apparu que les nanogels présent dans les PVA de DH =73 mole% et formés par interactions hydrophobe-hydrophobe entre séquences acétate ont des tailles entre 20-40 nm, avec des fractions volumiques de l'ordre de 20-30%. La désagrégation des nanogels par formation de complexes avec des tensioactifs anioniques du type SDS et SDBS a ensuite été démontrée. En faisant appel à la technique de fractionnement par " point de trouble " il est apparu que les chaînes les plus riches en acétate et en particulier celles ayant des longueurs des séquences acétate importantes complexent plus de SDS.Des " copolymères modèles " du type copolymères diblocs PVAc-b-PVOH comportant une séquence hydrophobe PVAc et une hydrophile PVOH ont pu être préparés par polymérisation RAFT, suivie par une réaction click. Une étude préliminaire de la micellisation de tels copolymères a permis de montrer la très grande analogie entre micelles de copolymères à blocs PVAc-b-PVOH et les nanogels de PVA examinés précédemment.
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Atanase, Léonard-ionut. "Contribution à l'étude des complexes Poly (vinyle alcool - vinyle acétate) / tensioactifs anioniques : caractéristiques colloïdales des nanogels et extension aux copolymères à blocs." Thesis, Mulhouse, 2010. http://www.theses.fr/2010MULH3728.
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Les copolymères poly (acétate de vinyle-co-alcool vinylique), désignés par PVA, sont des tensioactifs macromoléculaires obtenus par hydrolyse partielle de poly (acétate de vinyle)(PVAc). Si les propriétés tensioactives des PVA ont pu être corrélées aux caractéristiques moléculaires il n'en est par de même en ce qui concerne les associats du type nanogels présents dans les solutions aqueuses. L'objectif de cette thèse était de caractériser les nanogels par des techniques telles que la diffusion dynamique de la lumière, la chromatographie d'exclusion stérique et la viscosimétrie. 9 PVA, de degrés d'hydrolyse de 73 à 88 mole% et de degrés de polymérisation de 650 à 2500 ont été étudiés. Il est apparu que les nanogels présent dans les PVA de DH =73 mole% et formés par interactions hydrophobe-hydrophobe entre séquences acétate ont des tailles entre 20-40 nm, avec des fractions volumiques de l'ordre de 20-30%. La désagrégation des nanogels par formation de complexes avec des tensioactifs anioniques du type SDS et SDBS a ensuite été démontrée. En faisant appel à la technique de fractionnement par « point de trouble » il est apparu que les chaînes les plus riches en acétate et en particulier celles ayant des longueurs des séquences acétate importantes complexent plus de SDS.Des « copolymères modèles » du type copolymères diblocs PVAc-b-PVOH comportant une séquence hydrophobe PVAc et une hydrophile PVOH ont pu être préparés par polymérisation RAFT, suivie par une réaction click. Une étude préliminaire de la micellisation de tels copolymères a permis de montrer la très grande analogie entre micelles de copolymères à blocs PVAc-b-PVOH et les nanogels de PVA examinés précédemment<br>Poly (vinyl acetate-co-vinyl alcohol) copolymers, designated by PVA, are macromolecular surfactants obtained by partial hydrolysis of poly (vinyl acetate) (PVAc). If the surfactant properties of PVA have been correlated with molecular characteristics it is not the same for the colloidal aggregates in aqueous solutions so-called nanogels. The objective of this thesis was to characterize the nanogels using techniques such as dynamic light scattering, size exclusion chromatography and viscometry.9 PVA with degrees of hydrolysis between 73 and 88 mole% and polymerization degrees of 650 to 2500 were studied. It appeared that the nanogels, formed by hydrophobic-hydrophobic interactions between acetate sequences, are the size in the range of 20 to 40 nm with volume fractions between 20 and 30%. The disaggregation of nanogels by complex formation with anionic surfactants such as SDS and SDBS was further demonstrated. By using the "cloud point" fractionation technique it appeared that SDS is complexed by the sequences with high acetate content and in particular those with significant lengths of acetate sequences.As a model system diblock copolymers PVAc-b-PVOH containing a PVAc hydrophobie sequence and a PVOH hydrophilic sequence were prepared by RAFT polymerization, followed by a click reaction. A preliminary micellization study of these copolymers showed a very strong analogy between PVAc-b-PVOH block copolymer micelles and PVA nanogels discussed above
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Peng, Huan [Verfasser], Andrij Z. [Akademischer Betreuer] Pich, and Ulrich [Akademischer Betreuer] Schwaneberg. "Reactive stimuli-responsive poly(vinyl lactam) copolymers for design of nanogels based protein and drug carriers / Huan Peng ; Andrij Pich, Ulrich Schwaneberg." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1130402851/34.
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Ba, Maguette. "Reconstruction valvulaire aortique : Mise au point d’une prothèse en péricarde autologue prétraitée par un hydrogel de polysaccharide." Thesis, Paris 13, 2014. http://www.theses.fr/2014PA132055/document.
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Objectifs : Il n’existe pas de valve de remplacement idéale à l’heure actuelle. L’utilisation du péricarde autologue pour confectionner une valve de remplacement dans le même temps opératoire est une alternative intéressante. Le but de cette étude est de mettre au point une nouvelle méthode de préparation des tissus utilisant un gel polysaccahridique et de standardiser les techniques de préparation, de fabrication et d’implantation de la néo-valve péricardique. Méthodes : Au total 18 moutons ont été opérés pour un remplacement valvulaire aortique par autogreffe péricardique traitée par gel de polymère ou glutaraldéhyde dans les conditions physiologiques d’une chirurgie à coeur ouvert sous circulation extra-corporelle. La néo-valve a été implantée au niveau de l’anneau valvulaire natif par 3 hémi-surjets au Prolène 5/0 avec l’utilisation d’instruments dédiés conçus grâce à l’étude ex-vivo. Les moutons survivants sont sacrifiés à un an pour une évaluation histologique de l’implant tissulaire péricardique.Résultats : Le temps moyen de confection de l’autogreffe péricardique est de 15.68 +/- 4.84 mn, pour un temps de CEC moyen de 136.17 +/- 27.46 mn. Le temps de clampage aortique moyen est de 85.61 +/- 12.21mn. Le gradient moyen trans-valvulaire est de 4,1 mmHg. Les valves prétraitées au glutaraldéhyde sont plus massivement calcifiées que celles traitées par le gel de polymère.Conclusion : L’utilisation du péricarde autologue dans la reconstruction valvulaire aortique est une alternative intéressante surtout chez l’enfant et sur les petits anneaux. L’utilisation d’instruments dédiés permet de rendre la fabrication et l’implantation de la néo-valve plus simple et plus reproductible avec des temps de CEC et de clampage raisonnables. Le gel de polymère donne de meilleurs résultats histologiques que le glutaraldéhyde<br>Objective: Ideal prosthetic heart valve is not available. The use of the patient own pericardium for construction heart valve prosthesis is an interesting alternative and has several potential advantages. The aim of our study is to set up a new method for pericardium preparation with polysaccharide hydrogel and standardize the valve treatment processing and implantation.Méthods: Eighteen sheep underwent aortic valve replacement with autologous pericardium valve traited with polymeric gel or glutaraldéhyde using cardio-pulmonary bypass. The pericardial prosthesis was implanted with a proximal running 5/0 Prolène sutures placed along the aortic annulus and utilization of specially designed instruments. Survival sheep were euthanized after 12 months for histologic evaluation of the pericardial valvular implant.Results: Cardiopulmonary bypass and cross-clamp mean time was 136.17 +/- 27.46 mn and 85.61 +/- 12.21mn respectively. The prosthesis mean time construction was 15.68 +/- 4.84 mn. The mean transvalvular gradient after implantation was 4,1mmHg. The autologous pericardial valves treated with glutaraldehyde tended to show more extensive calcification than pericardial valves treated with polymeric gel.Conclusion: Truly stenless aortic valve replacement using autologous pericardium is feasible with cross clamping time acceptable and technically reliable with the use of specially designed instruments. The use of polymeric gel for treatment of autologous pericardial valve is less aggressive than glutaraldéhyde
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Guo, Qiong. "Surfactants in nonpolar oils: agents of electric charging and nanogel templates." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43622.
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This thesis studies the formation of mobile and surface-bound electric charges in nonpolar liquids. Unlike aqueous media with their natural abundance of charged species, liquids of low dielectric constant do not readily accommodate charges, but can do so in the presence of certain surfactant additives. Surfactant-mediated charging in nonpolar oils has long been exploited industrially, but the underlying charging mechanisms are far from understood. The present work seeks clarification by comparing the effect of ionic and nonionic surfactants on the conductivity of nonpolar solutions and the electrophoretically observable surface charge of suspended polymer particles. Both types of surfactant are found to generate mobile ions in solution as well as particle charge; and in the more surprising case of nonionic surfactants, the occurrence of particle charge and screening ions is confirmed independently by measurements of the electrostatic particle interaction energy. A systematic variation of the particle material and functionalization, the residual water content, and the surfactant concentration above and below the critical micelle concentration provides insights about the possible charging pathways.
Reverse surfactant micelles are explored not only as charging agents, but also as reactors and templates for the synthesis of novel nanogels with promise for drug delivery. Synthesis via copper-free Click chemistry is shown to allow for better control of the particle size than a more conventional polymerization scheme, while avoiding metal catalysts and free radicals that are considered hazardous for most biomedical applications.
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Zahouani, Sarah. "Development of new types of mechanocatalytic systems." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAE037/document.
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Le fascinant processus par lequel les signaux mécaniques sont transformés en réactions biochimiques dans la nature est appelé mécano-transduction. Le but de ma thèse a été de mimer la Nature en élaborant de nouveaux systèmes enzymatiques mécano-transductifs, i.e des matériaux capables de moduler une catalyse enzymatique lorsqu’ils sont sollicités mécaniquement. Nous avons d’abord étudié l’effet de l’étirement sur les chaînes constitutives de films multicouches de polyélectrolytes, matrices souvent utilisées pour le développement de biomatériaux intelligents. Dans le cadre d’une nouvelle stratégie axée sur la modulation mécanique de la conformation, nous avons ensuite élaboré des matrices étirables à base de poly(éthylène glycol)s. Nous avons en particulier développé de tout nouveaux revêtements covalents appelés nanogels qui se sont avérés être déposables sur le silicone étirable et fonctionnalisables avec différentes biomacromolécules, ouvrant ainsi de nouvelles routes biomimétiques<br>The fascinating process by which mechanical signals are transformed into biochemical reactions in Nature is called mechanotransduction. The goal of my PhD was to mimic Nature by elaborating new types of mechanocatalytic materials, i.e materials able to modulate a catalytic activity when mechanically stimulated. We first aimed at understanding the impact of stretching on the structural properties of polyelectrolyte multilayers films, polymeric matrices often used for the design of smart biomaterials. Within the framework of a new strategy essentially relying on mechanically induced conformational changes, we then developed stretchable polymeric matrices based on poly(ethylene glycol)s. We more particularly designed new types of covalent coatings, called nanogels. We showed that these architectures were buildable on stretchable silicone and that they could be functionalized with different types of biomacromolecules; thus opening new biomimetic routes