Orientador: Julio Roberto Bartoli / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-06T09:00:39Z (GMT). No. of bitstreams: 1 Padilha_GiovanadaSilva_M.pdf: 1555922 bytes, checksum: 035b74427e55cfdd28217830ff384c88 (MD5) Previous issue date: 2005 / Resumo: Dispositivos ópticos poliméricos têm sido promissores para aplicação em comunicações, principalmente na utilização em redes de curta distância devido ao fácil processamento e baixo custo quando comparado aos materiais ópticos fabricados com sílica. Na fabricação de um dispositivo óptico é imprescindível que o índice de refração do núcleo seja maior do que o da casca para que o sinal seja transmitido pelo dispositivo. Algumas técnicas de tratamento superficiais são muito comuns para obter diferentes índices de refração entre os materiais, entre elas a fluoração por plasma, seja por reações de deposição ou substituição, formando-se uma camada de polímero fluorado sobre um substrato polimérico com índice de refração modificado. Neste trabalho, estudou-se a modificação da superfície de filmes de poli (metacrilato de metila) (PMMA), usando a técnica de polimerização por plasma de gás fluorado. Filmes de PMMA com espessura de 1 O _m foram obtidos por Spin-Coating a partir de uma solução de clorofórmio (15,36% em massa de PMMA). Os filmes foram expostos ao plasma de CHF3 seguindo dois planejamentos fatoriais em diferentes níveis de pressão e tempo. A superfície dos filmes ópticos fluorados produzidos foi caracterizada através das técnicas: gravimetria, espectroscopia no infravermelho (FTIR-A TR), ângulo de contato de molhamento, microscopia óptica, microscopia eletrônica de varredura (MEV), microscopia de força atômica (AFM) e perfilometria. A fluoração da superfície dos filmes de PMMA pode ser inferida pelo aumento do ângulo de contato em todas as condições experimentais e confirmadas através das análises de FTIR-A TR. As análises gravimétricas apresentaram aumento da camada fluorada sobre o filme de PMMA em toàas as condições de processo, estimando a maior espessura próxima a 1,55 _m em 0,7 torr e 40 minutos de plasma. A análise estatística mostrou que a pressão e o tempo foram variáveis significativas (95% de confiança) para o crescimento de camada polimérica fluorada. Análises de MEV apresentaram uma camada fluorada bem definida e presença do elemento flúor com a análise de EDS. A rugosidade dos filmes ópticos fluorados foi de 200 Á, bastante satisfatório para cladding com 1,55 _m de espessura / Abstract: Polymeric optical devices have been promising for application in communications, mainly for local networks due to easy processing and low cost compared to the optical materials made silica. In the production of an optical device it is indispensable the difference between the refraction index of the core and the cladding. The refractive index of the core should be larger than the one of the cladding so that the signal is transmitted by the device. Some techniques of surface treatment are very common to obtain different refractive index among the materials, among them plasma fluorination that either allow deposition reaction of a layer of fluorinated polymers the substrate with refractive index modified. In this work, it was studied the modification of the surface of poly (methyl methacrylate) (PMMA) films, with the technique of plasma polymerization. Films of PMMA with thickness of 1 O _m were obtained by Spin-Coating starting from a chloroform solution (15.36% wt% PMMA). The films were exposed to the plasma of CHF3 following two factorial experimental designs at different levels of pressure and time. The surface of the films was characterized through the techniques: gravimetry, infrared spectroscopy (FTIR-ATR), contact angle of wetting, optical microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM) and scan profile. The surface fluorination of PMMA films can be inferred by the increase of the contact angle in all of the experimental conditions and confirmed with the analyses of FTIR-ATR. Gravimetry showed an increase of the layer of fluorinated polymer onto PMMA films, being 1.55 _m the largest thickness at 0.7 torr and 40 minutes of plasma. The factorial analysis showed that pressure and time were significant (95% of confidence) for the growth of the fluorinated polymeric layer. Analyses of SEM showed a layer of fluorinated polymer well defined and presence of the fluorine element by EDS analysis. The roughness of the films fluorinated polymers was around of 200 A, quite satisfactory for cladding of 1.55 micro m of thickness / Mestrado / Ciencia e Tecnologia de Materiais / Mestre em Engenharia Química

The role of a protein-repelling coating is to limit the interaction between a device and its physiological environment. Plasma-polymerized-PEG (pp-PEG) surfaces are of great interest since they are known to avoid protein adsorption. and cell attachment. However, in all the studies previously published in the literature, the PEG coatings have been prepared using low pressure processes. <p>In this thesis, we synthesize biocompatible pp-PEG coatings using atmospheric pressure plasma. Two original methods are developed to obtain these pp-PEG films. 1. Atmospheric pressure plasma liquid deposition (APPLD) consists in the injection of the precursor, tetra(ethylene glycol)dimethylether (tetraglyme), by means of a liquid spray, directly in the post-discharge of an atmospheric argon plasma torch. 2. In atmospheric pressure plasma-enhanced chemical vapor deposition (APPECVD), tetraglyme vapors are brought in the post-discharge trough a heating sprinkler. The chemical composition, as well as the non-fouling properties of the APPLD and APPECVD films, are compared to those of PEG coatings synthesized by conventional low pressure plasma processes.<p>In the first part of the study, the effect of the power on the chemical composition of the films has been investigated by infrared reflection absorption spectroscopy (IRRAS), X-ray photoelectron spectroscopy (XPS) and secondary ions mass spectroscopy (SIMS). <p>The surface analysis reveals that for the APPECVD samples, the fragmentation of the precursor increases as the power of the treatment is increased. In other terms, the lower the plasma power is, the higher the “PEG character” of the resulting films is. Indeed, the C-O component (286.5 eV) of the XPS C 1s peak is decreasing while the hydrocarbon component (285 eV) is increasing as the power of the plasma is increased. The same conclusion can be drawn from the signature ToF-SIMS peaks (m/z = 45 (CH3&61485;O&61485;CH2+ and +CH2CH2&61485;OH), 59 (CH3&61485;O&61485;CH2&61485;CH2+), 103 (CH3&61485;(O&61485;CH2&61485;CH2)2+)) that are decreasing in the case of high power treatments. Accordingly, IRRAS measurements show that the C-O stretching band is decreasing for high power plasma deposition. This is in agreement with the observations made from the analysis of the LP PECVD coatings and from the literature.<p>The films deposited by the APPLD process do not show the same behavior. Indeed, whatever the power injected into the discharge is, we are able to achieve films with a relatively high PEG character (&61566;83 %).<p>The second part of this study is dedicated to the evaluation of the non-fouling properties of the coatings by exposing them to proteins (bovine serum albumin and human fibrinogen) and cells (mouse fibroblasts (L929 and MEF)) and controlling the adsorption with XPS (proteins) and SEM (cells).<p>For the APPECVD samples, a low plasma power (30 W) leads to an important reduction of protein adsorption and cell adhesion (over 85%). However, higher-powered treatments tend to reduce the non-fouling ability of the surfaces (around 50% of reduction for a 80 W deposition). <p>The same order of magnitude (over 90% reduction of the adsorption) is obtained for the APPLD surfaces, whatever is the power of the treatment. <p>Those results show an important difference between the two processes in terms of power of the plasma treatment, and a strong relationship between the surface chemistry and the adsorption behavior: the more the PEG character is preserved, the more protein-repellent and cell-repellent is the surface. / Le rôle d’une couche empêchant l’adsorption de protéines est de limiter les interactions entre un implant et le milieu physiologique auquel il est exposé. Les films de poly(éthylène glycol) polymérisés par plasma (pp-PEG) sont d’intérêt majeur car ils sont connus pour empêcher l’adsorption de protéines ainsi que l’attachement cellulaire. Cependant, dans toutes les études publiées précédemment, les couches de type PEG ont été réalisées sous vide.<p>Dans cette thèse de doctorat, nous synthétisons des couches de type pp-PEG biocompatibles par plasmas à pression atmosphérique. A cette fin, deux méthodes originales ont été développées. 1. La première méthode consiste en l’injection du précurseur, le tetra(éthylène glycol) diméthyl éther (tetraglyme), en phase liquide, en nébulisant ce dernier au moyen d’un spray, directement dans la post-décharge d’une torche à plasma atmosphérique fonctionnant à l’argon. En anglais, nous appelons ce procédé « Atmospheric pressure plasma liquid deposition (APPLD) ». 2. Dans la deuxième méthode, appelée en anglais « Atmospheric pressure plasma-enhanced chemical vapor deposition (APPECVD)», le tetraglyme est amené en phase vapeur dans la post-décharge, au moyen d’un diffuseur chauffant. La composition chimique des dépôts de type APPLD et APPECVD, ainsi que leurs propriétés d’anti-adsorption sont évaluées, et comparées aux dépôts pp-PEG obtenus par les méthodes à basse pression conventionnelles.<p>Dans la première partie de cette étude, nous nous focalisons sur la composition chimique des films déposés, et plus particulièrement sur l’influence de la puissance injectée dans le plasma sur cette composition chimique. A cette fin, nous avons fait appel à des techniques d’analyse telles que la spectroscopie de réflexion-absorption infrarouge (IRRAS), la spectroscopie des photoélectrons X (XPS) et la spectrométrie de masse des ions secondaires (SIMS). <p>Il en ressort que les films de type APPECVD perdent progressivement leur « caractère PEG » à mesure que la puissance de la décharge plasma est élevée. Cela serait dû à une plus grande fragmentation du précurseur dans la post-décharge d’un plasma plus énergétique. Cette tendance est cohérente avec ce que nous avons observé pour les dépôts à basse pression ainsi que dans la littérature.<p>Dans le cas des films de type APPLD, un tel comportement n’a pas été mis en évidence :quelle que soit la puissance dissipée dans le plasma, les films présentent un « caractère PEG » relativement élevé.<p>La deuxième partie de cette thèse est dédiée à l’évaluation des propriétés d’anti-adsorption des films synthétisés, en les exposant à des protéines (albumine de sérum bovin et fibrinogène humain) et des cellules (fibroblastes de souris, L929 et MEF). L’adsorption de protéines est contrôlée par XPS tandis que l’attachement cellulaire est contrôlé par imagerie SEM.<p>Pour les échantillons de type APPECVD, un dépôt à faible puissance (30 W) mène à une importante réduction de l’adsorption de protéines et de cellules (> 85%) tandis qu’à de plus hautes puissances (80 W), l’anti-adsorption est sensiblement diminuée (50% de réduction). Dans le cas des dépôts de type APPLD, quelle que soit la puissance du plasma, une forte diminution de l’adsorption de protéines et de cellules est observée (> 90 %).<p>Ces résultats montrent une différence majeure entre les deux procédés quant à l’influence de la puissance du plasma ainsi qu’une forte relation entre la composition chimique de la surface synthétisée et son pouvoir d’anti-adsorption :plus le « caractère PEG » du dépôt est conservé, plus la surface empêchera l’interaction avec les protéines et les cellules. <p><p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

The diploma thesis deals with the treatment of polycaprolactone (PCL) nanofibers. PCL fibers were subjected to the deposition of plasma amine polymers in a low pressure pulsed radiofrequency capacitively coupled discharge using cyclopropylamine monomer (CPA). Collagen as an extracellular matrix (ECM) protein was immobilized and cell proliferation on the modified nanofiber surface was monitored. Untreated PCL fibers were also subjected to the deposition of an antibacterial copper layer, and the fibers were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and energy dispersive spectroscopy (EDX).

Title: Multicomponent plasma polymers with spatially controlled properties Author: MSc. Pavel Pleskunov Department / Institute: Department of Macromolecular Physics/Charles University Supervisor of the doctoral thesis: Prof. Ing. Andrey Shukurov, PhD, Department of Macromolecular Physics / Charles University Abstract: Mixing of two (or more) polymers often leads to phase separation and to the formation of nanoscale architecture, which can be highly attractive in various applications including controllable drug delivery, fabrication of separation and solid electrolyte membranes, gas storage, etc. Different wet-chemistry techniques already exist to produce nanophase-separated polymers; however, capturing the resultant polymeric structure in a predictable manner remains a challenging task. In this thesis, a low-temperature plasma-based strategy is investigated for the production of multicomponent thin films of plasma polymers with spatially discriminated nanoscale domains. Gas aggregation cluster source is used for the fabrication of nanoparticles of plasma polymerized acrylic acid, whereas Plasma-Assisted Vapor Phase Deposition is used for the deposition of thin films of poly(ethylene oxide) plasma polymer. Embedding of nanoparticles into matrices of thermodynamically incompatible plasma polymer as well as...

La medicina regenerativa és una disciplina que ha guanyat reconeixement en les últimes dècades pel fet que moltes malalties no són tractables amb fàrmacs convencionals. Molts grups de recerca i empreses inverteixen temps i diners en la producció de nous paradigmes per curar malalties com el Parkinson, l'artrosi o la regeneració de medul·la espinal. Aquestes propostes es basen en l'ús de teixits biomimètics per reparar òrgans danyats. En aquesta tesi es presenta un nou model experimental per estudiar la formació d'os i cartílag i eventualment la reparació d'aquests teixits. Hem utilitzat Fibroblasts Embriònics de Ratolí (MEFs) combinats amb diferents materials biomimètics per estudiar os i cartílag in vitro i in vivo. Aquests MEFs es van cultivar in vitro i in vivo en RAD16-I, un pèptid auto-ensamblable amb estructura similar a matrius extracel·lulars genèriques, amb l'objectiu d'estudiar l'evolució dels fibroblasts en aquestes dues condicions. També s'han recobert superficialment micropartícules de hidroxiapatita obtenint càrregues inorgàniques similars a l'os i biològicament actives per a utilitzar-les com a substituts d'os o cartílag. Amb la idea de millorar els recobriments superficials, hem desenvolupat una plataforma que permet dur a terme proves combinatòries amb factors de creixement i altres compostos biològicament actius. Cultius in vitro de MEFs han mostrat que quan fibroblasts embrionaris primaris de ratolí es cultiven en RAD16-I, estableixen una xarxa intercel·lular que causa una contracció cel·lular organitzada, proliferació i migració cel·lulars i culmina amb la formació d'una estructura bilateral i simètrica amb un eix central distingible. Durant aquest procés morfològic, augmenta l'expressió d'un grup de gens mesodèrmics (brachyury, Sox9, Sox5, Sox6, Runx2). L'expressió de brachyury està localitzada primer en l'eix de simetria central i després s'extén als dos costats de l'estructura. Per acabar, la formació espontània d'un teixit similar al del cartílag acompanya l'expressió de Sox9 i Runx2.L'estudi in vivo de MEFs es va fer gràcies a la tècnica de presa d'imatges no invasiva basada en bioluminiscència (BLI) que ha desenvolupat en el grup de recerca del dr. Jerónimo Blanco. Aquests experiments han mostrat que el RAD16-I és una matriu molt permissiva per a la supervivència i proliferació cel·lulars in vivo. A més, sembla que les pobres propietats mecàniques que té el RAD16-I no li suposen cap desavantatge en termes de creixement cel·lular in vivo. Finalment, hem desenvolupat diferents tipus de micropartícules de hidroxiapatita (HA) no recobertes, i recobertes mitjançant polimerització assistida per plasma. Els recobriments permeten afinar les propietats de la HA i produir partícules que satisfacin les necessitats de diferents aplicacions mèdiques en reparació d'os i cartílag. També hem desenvolupat un mètode per produir plataformes basades en plaques de 96 pous que permetin fer proves combinatòries amb compostos biològicament actius per vàries aplicacions en medicina regenerativa. En conclusió, hem aportat noves idees i eines que permetran trobar teixits regeneratius basats en l'ús de fibroblasts i materials biomimètics. / La medicina regenerativa es una disciplina que ha ganado reconocimiento en las últimas décadas porque muchas enfermedades no son tratables con fármacos convencionales. Muchos grupos de investigación y empresas invierten tiempo y dinero en la producción de nuevos paradigmas para curar enfermedades como el Parkinson, la artrosis o la regeneración de médula espinal. Estas propuestas se basan en el uso de tejidos biomiméticos para reparar órganos dañados. En esta tesis se presenta un nuevo modelo experimental para estudiar la formación de hueso y cartílago y tal vez la reparación de estos tejidos. Hemos utilizado Fibroblastos Embrionarios de Ratón (MEFs) combinados con diferentes materiales biomiméticos para estudiar hueso y cartílago in vitro e in vivo. Estos MEFs se cultivaron in vitro e in vivo en RAD16-I, un péptido auto-ensamblable con estructura similar a matrices extracelulares genéricas, con el objetivo de estudiar la evolución de los fibroblastos en estas dos condiciones. También se han recubierto superficialmente micropartículas de hidroxiapatita obteniendo cargas inorgánicas similares al hueso y biológicamente activas para utilizarlas como sustitutos de hueso o cartílago. Con la idea de mejorar los recubrimientos superficiales, hemos desarrollado una plataforma que permite llevar a cabo pruebas combinatorias con factores de crecimiento y otros compuestos biológicamente activos. Cultivos in vitro de MEFs han mostrado que cuando fibroblastos embrionarios primarios de ratón se cultivan en RAD16-I, establecen una red intercelular que causa una contracción celular organizada, proliferación y migración celulares y culmina con la formación de una estructura bilateral y simétrica con un eje central distinguible. Durante este proceso morfológico, aumenta la expresión de un grupo de genes mesodérmicos (brachyury, Sox9, Sox5, Sox6, Runx2). La expresión de brachyury está localizada primero en el eje de simetría central y después se extiende a los dos lados de la estructura. Para terminar, la formación espontánea de un tejido similar al del cartílago acompaña a la expresión de Sox9 y Runx2.El estudio in vivo de MEFs se hizo gracias a la técnica de toma de imágenes no invasiva basada en bioluminiscencia (BLI) que han desarrollado en el grupo de investigación del dr. Jerónimo Blanco. Estos experimentos han mostrado que el RAD16-I es una matriz muy permisiva para a la supervivencia y proliferación celulares in vivo. Además, parece que las pobres propiedades mecánicas que tiene el RAD16-I no le suponen ninguna desventaja en términos de crecimiento celular in vivo. Finalmente, hemos desarrollado diferentes tipos de micropartículas de hidroxiapatita (HA) no recubiertas, y recubiertas mediante polimerización asistida por plasma. Los recubrimientos permiten afinar las propiedades de la HA y producir partículas que satisfagan las necesidades de diferentes aplicaciones médicas en reparación de hueso y cartílago. También hemos desarrollado un método para producir plataformas basadas en placas de 96 pozos que permitan hacer pruebas combinatorias con compuestos biológicamente activos para varias aplicaciones en medicina regenerativa. En conclusión, hemos aportado nuevas ideas y herramientas que permitirán hallar tejidos regenerativos basados en el uso de fibroblastos y materiales biomiméticos. / Regenerative medicine is a discipline that has gained recognition in the last decades because many diseases are not treatable with traditional drugs. Many research groups and companies invest time and money in the production of new paradigms to cure conditions such as Parkinson's, arthrosis or spinal cord injuries. These approaches are based in the use of biomimetic tissues to replace damaged organs. In this work we present a new experimental model to study the formation of bone and cartilage and eventually to repair these tissues. We have used Mouse Embryonic Fibroblasts (MEFs) combined with different biomimetic materials to study bone and cartilage formation in vitro and in vivo. MEFs have been cultured in vitro and in vivo in RAD16-I, a synthetic self-assembling peptide with structure similar to generic extracellular matrix milieu, to study the evolution of these fibroblasts in both conditions. Also, hydroxyapatite microparticles have been surface coated to produce biologically active bone-like inorganic charges for use in cartilage or bone substitutes. In order to improve the particles' coatings, we have developed a platform that allows us to perform combinatorial testing of growth factors and other biologically active compounds. In vitro cultures of MEFs has shown that when primary mouse embryonic fibroblasts are cultured in a soft nanofiber scaffold, they establish a cellular network that causes an organized cell contraction, proliferation, and migration that ends in the formation of a symmetrically bilateral structure with a distinct central axis. A subset of mesodermal genes (brachyury, Sox9, Sox5, Sox6, Runx2) is upregulated during this morphogenetic process. The expression of brachyury was localized first at the central axis, extending then to both sides of the structure. The spontaneous formation of cartilage-like tissue mainly at the paraxial zone followed the expression of Sox9 and Runx2.In vivo study of MEFs was facilitated by a non-invasive bioluminescence imaging (BLI) technique to detect luciferase-expressing cells, developed by Dr. Blanco's research group. These experiments showed that RAD16-I is a very permissive scaffold for cell survival and proliferation in vivo. Furthermore, it seems that the poor mechanical properties of RAD16-I are no disadvantage in terms of cell growth in vivo.Finally, we have developed different types of coated and uncoated hydroxyapatite (HA) microparticles by plasma polymerization. The coatings permit to tune the properties of HA and produce particles that suit the needs of different medical applications in bone and cartilage repair. Moreover, we have developed a method to produce platforms based on 96-well plates that allow the combinatorial testing of biologically active compounds for various applications in regenerative medicine. In conclusion, we have supplied new insights and tools that will enhance the finding of new regenerative tissues based on fibroblasts and biomimetic materials.

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