Ces travaux de thèse portent sur les phénomènes d’amplification du signal de diffusion Raman par effet de surface et par effet de pointe. Des réseaux de motifs métalliques de taille nanométrique arrangés spatialement ont été fabriqués par la méthode de transfert Langmuir-Blodgett et par lithographie à faisceau d’électrons. De telles structures de géométries contrôlées déposées à la surface de lamelles de microscope ont été développées afin d’amplifier le signal Raman de molécules adsorbées par effet SERS (Surface Enhanced Raman Spectroscopy). Ces nanostructures triangulaires en or de taille proche de la longueur d’onde ont des bandes de résonance plasmon dans le domaine spectral visible. En utilisant une source de laser appropriée dans ce domaine spectral, les facteurs d’amplification Raman d’une couche mono-moléculaire d’un dérivé azobenzène sont de plusieurs ordres de grandeur, et ce pour les deux techniques de nano-lithographie employées. Afin de compléter ces premiers résultats, des réseaux de fils d’or avec de grands facteurs de forme ont été fabriqués. Ces derniers montrent des résonances plasmons multipolaires et des facteurs d’amplification de l’ordre de 105. Les techniques de microscopie en champ proche ont également été développées afin de localiser précisément l’exaltation Raman et d’accroitre la résolution spatiale de mesures Raman. Des pointes métalliques en or de taille nanométrique ont ainsi permis d’amplifier localement le signal de diffusion de molécules placées à leur proximité par effet TERS (Tip Enhanced Raman Spectroscopy). Les développements logiciels et mécaniques entre un microscope confocal Raman et un microscope à force atomique ont été implémentés afin de contrôler simultanément les deux instruments. Ce montage expérimental a été appliqué à l’étude de nanofils semi-conducteurs de nitrure de gallium permettant de suivre leur signal vibrationnel avec une résolution spatiale inférieure à 200 nm. / This thesis work focuses on Raman scattering enhancements by metallic nanostructures. In the first part of this work, arrays of metallic patterns with nanometer dimensions were fabricated by the Langmuir-Blodgett deposition technique and electron-beam lithography. Such structures made of gold were fabricated onto microscope slides with the goal to enhance the Raman signal through SERS effect (Surface Enhanced Raman Spectroscopy). These patterns formed by an assembly of triangular nanostructures with sizes of hundreds of nanometers, exhibit plasmon resonance bands in the visible spectral region. By using an appropriate excitation laser source with respect to the plasmon frequency, Raman enhancement factors of a monolayer were found to be of several order of magnitude for both Langmuir-Blodgett and electron-beam lithography platforms. To further complement these results, gold wires arrays with large aspect ratio made by electron-beam lithography showed multipolar plasmon resonances with enhancement factors up to 105. In the second part of this thesis, near-field Raman microscopy has been developed with the aim to localize precisely the Raman enhancement and improve spatial resolution of Raman measurements. Atomic force microscopy gold tips have been used to locally enhance scattering signal of molecules in close proximity to the tip opening new opportunities. This approach known as TERS (Tip Enhanced Raman Spectroscopy) is of significant interest to probe nanomaterials, nanostructures or monolayers. Software and mechanical developments have been made between a confocal Raman microscope and an atomic force microscope to control simultaneously both instruments. This experimental setup was used to characterize gallium nitride semi-conductors nanowires with spatial resolution better than 200 nm.

A investigação dos mecanismos de interação dos vírus com as células do hospedeiro trazem informações relevantes para a identificação de alvos no desenvolvimento de drogas para impedir a penetração e/ou desenvolvimento dos vírus. Peptídeos desenhados a partir de proteínas virais foram desenvolvidos e testados quanto as suas capacidades de inibir o processo de fusão do vírus com a célula do hospedeiro. Alguns se encontram em fase de avaliação clínica. Anticorpos contra a proteína p24 do HIV-1 foram detectados no soro de pacientes HIV-positivos, e estes reconhecem pequenas seqüências peptídicas desta proteína. Neste trabalho foi analisada a interação entre uma seqüência peptídica correspondente aos aminoácidos 196-224 (AAMQMLKETINEEAAEWDRVHPVHAGPIA) da proteína p24, denominado p24- 1, com sistemas biomiméticos. Os sistemas utilizados foram filmes de Langmuir (monocamadas) de dipalmitoil fosfatidil colina (DPPC) e dipalmitoil fosfatidil glicerol (DPPG) e vesículas multilamelares (MLVs) de DPPC. O p24-1 encontra-se desorganizado em solução aquosa, mas com a interação com as MLVs de DPPC teve induzido uma conformação hélice ?, de acordo com o espectro de dicroísmo circular (CD). Esta característica foi confirmada pela predição de hélice a seguida por uma estrutura não ordenada contendo 11 resíduos do p24-1. As isotermas de pressão e potencial de superfície das monocamadas de DPPC foram afetadas com a presença de 0,05% mo1 de p24-1, com uma expansão de aproximadamente 5%. Para concentrações acima de 0,5% mo1 de p24-1 a expansão foi de 20%, com saturação do efeito da concentração. O efeito de expansão foi acompanhado por uma alteração na morfologia das monocamadas, estudados com microscopia no ângulo de Brewster (BAM). A incorporação do p24-1 impede a formação de grandes domínios de DPPC. O efeito cooperativo causado na monocamada de fosfolipídios pelo p24-1 sugere que esse tem um potencial na atividade antiviral por participar da expansão da membrana da célula hospedeira. / The investigation of the interaction mechanisms between the viruses and the host cells brings relevant information for the identification of targets on the development of drugs to prevent the penetration and/or development of the viruses. Peptides designed from viral proteins have been developed and tested on its capacities of inhibiting the merging process of the virus with the host cell. Some of them are in clinical evaluation. Antibodies against the protein p24 of the HIV-1 have been detected in the serum of HIV-positive patients, and they are able to recognize short peptide sequences of this protein. In this work, it was analyzed the interaction between a peptide sequence corresponding to amino acids 196-224 (AAMQMLKETINEEAAEWDRVHPVHAGPIA) of the protein p24, called p24- 1, and biomimetic systems. The systems used were Langmuir films (monolayers) of dipalmitoyl phosphatidyl choline (DPPC) and dipalmitoyl phosphatidyl glycerol (DPPG) and multilamelar vesicles (MLVs) of DPPC. p24-1 is found disorganized in watery solution, but with the interaction with the MLVs of DPPC it had induced a conformation ?-helix, according to the circular dichoism spectra (CD). This characteristic was confirmed by the prediction of ?-helix followed by an unordered structure with 11 residues of p24-1. The isotherms of pressure and potential of surface of the DPPC monolayers were affected by the presence of 0,05% mo1 of p24-1, with an expansion of approximately 5%. For concentrations above 0,5% mol of p24-1 the expansion was 20%, with saturation of the concentration effect. The expansion effect was followed by a morphologic alteration of the monolayers, studied with microscopy of the Brewster angle (BAM). The incorporation of p24-1 prevents the formation of large domains of DPPC. The cooperative effect caused in the phospholipid monolayer by p24-1 suggests that this peptide has a potential in the antiviral activity, once its participates on the expansion of the host cell membrane.

Made available in DSpace on 2017-07-10T19:24:24Z (GMT). No. of bitstreams: 1 Mariana_ sbizzaro.pdf: 1501907 bytes, checksum: 5610159e30f98d52848320f90146f751 (MD5) Previous issue date: 2016-02-12 / The agricultural sector has great influence in Brazilian economy. Furthermore, agricultural yield has been associated with pesticides application during crop cycle, which atrazine is applied for example, since it can cause environmental contamination when it does not reach its target. Thus, there are some essential and imperative options that can minimize contamination and negative impacts during agricultural practices. So, present study aimed at evaluating the ability of three biochars in atrazine adsorption. Therefore, three biochars produced from bamboo culm were used, whose species is Phyllostachys aurea, and temperature ranged at 350 ºC, 450 ºC and 550 ºC. The three studied biochars were named as BE350, BE450 and BE550. They were characterized based on their physical and chemical properties by elemental analysis, characterization of functional groups (Infrared Spectroscopy Fourier Transform - FTIR), surfaces morphology evaluation (Scanning Electron Microscopy - SEM) as well as specific surface area (ASEBET) and porosity. A kinetic study was carried out to determine the equilibrium period of adsorption process and the kinetic mechanism that controls such process. Langmuir and Freundlich isotherms were also modeled during this trial. Atrazine determination, after the adsorption test, was carried out by High Performance Liquid Chromatography (HPLC). The obtained analyses showed that the adsorption capacity of biochars decreased in the following order: BE 450> BE 350 > BE 550, and such capacity has been associated with the physical and chemical characteristics of biochars. The three studied biochars are well represented by the kinetic model of pseudo-second order. At last, all biochars have shown high affinity to adsorb atrazine; however, the biochar that was produced at 450 ºC has shown the highest adsorption capacity. / O setor agrícola possui grande destaque na economia brasileira, a produção agrícola está associada ao uso de pesticidas durante o ciclo das culturas, como é o caso da atrazina, que pode causar a contaminação do ambiente, quando não atinge seu alvo. Sendo assim, alternativas que minimizem as contaminações e impactos negativos da prática agrícola são essenciais e urgentes. Desta forma, o presente estudo teve por objetivo avaliar a capacidade de três biocarvões, em adsorver o herbicida atrazina. Para tanto, foram utilizados três biocarvões, produzidos a partir do colmo de bambu, da espécie Phyllostachys aurea à 350ºC, 450ºC e 550ºC, nomeados BE350, BE450 e BE550. Os biocarvões foram caracterizados quanto as propriedades físicas e químicas, por meio de análise elementar, caracterização de grupos funcionais (Espectroscopia de Infravermelho com Transformada de Fourier - FTIR), avaliação da morfologia das superfícies (Microscopia Eletrônica de Varredura - MEV), bem como, área superficial específica (ASEBET) e porosidade. Estudo cinético foi realizado, visando determinar o tempo de equilíbrio do processo de adsorção, bem como, o mecanismo cinético que controla o processo. Também foram modeladas isotermas de Langmuir e Freundlich. A determinação da atrazina, após os ensaios de adsorção, foi realizada por Cromatografia Líquida de Alta Performance (CLAE). As análises realizadas apontaram que a capacidade de adsorção dos biocarvões diminuiu na ordem de BE 450 > BE 350 > BE 550, e tal capacidade está associada às características físicas e químicas dos biocarvões. Os três biocarvões são bem representados pelo modelo cinético de pseudo-segunda ordem. Todos biocarvões exibiram elevada afinidade para a adsorção do herbicida atrazina, contudo, o biocarvão produzido à 450 ºC demonstra maior capacidade de adsorção

Made available in DSpace on 2017-05-12T14:47:40Z (GMT). No. of bitstreams: 1 Mariana_ sbizzaro.pdf: 1501907 bytes, checksum: 5610159e30f98d52848320f90146f751 (MD5) Previous issue date: 2016-02-12 / The agricultural sector has great influence in Brazilian economy. Furthermore, agricultural yield has been associated with pesticides application during crop cycle, which atrazine is applied for example, since it can cause environmental contamination when it does not reach its target. Thus, there are some essential and imperative options that can minimize contamination and negative impacts during agricultural practices. So, present study aimed at evaluating the ability of three biochars in atrazine adsorption. Therefore, three biochars produced from bamboo culm were used, whose species is Phyllostachys aurea, and temperature ranged at 350 ºC, 450 ºC and 550 ºC. The three studied biochars were named as BE350, BE450 and BE550. They were characterized based on their physical and chemical properties by elemental analysis, characterization of functional groups (Infrared Spectroscopy Fourier Transform - FTIR), surfaces morphology evaluation (Scanning Electron Microscopy - SEM) as well as specific surface area (ASEBET) and porosity. A kinetic study was carried out to determine the equilibrium period of adsorption process and the kinetic mechanism that controls such process. Langmuir and Freundlich isotherms were also modeled during this trial. Atrazine determination, after the adsorption test, was carried out by High Performance Liquid Chromatography (HPLC). The obtained analyses showed that the adsorption capacity of biochars decreased in the following order: BE 450> BE 350 > BE 550, and such capacity has been associated with the physical and chemical characteristics of biochars. The three studied biochars are well represented by the kinetic model of pseudo-second order. At last, all biochars have shown high affinity to adsorb atrazine; however, the biochar that was produced at 450 ºC has shown the highest adsorption capacity. / O setor agrícola possui grande destaque na economia brasileira, a produção agrícola está associada ao uso de pesticidas durante o ciclo das culturas, como é o caso da atrazina, que pode causar a contaminação do ambiente, quando não atinge seu alvo. Sendo assim, alternativas que minimizem as contaminações e impactos negativos da prática agrícola são essenciais e urgentes. Desta forma, o presente estudo teve por objetivo avaliar a capacidade de três biocarvões, em adsorver o herbicida atrazina. Para tanto, foram utilizados três biocarvões, produzidos a partir do colmo de bambu, da espécie Phyllostachys aurea à 350ºC, 450ºC e 550ºC, nomeados BE350, BE450 e BE550. Os biocarvões foram caracterizados quanto as propriedades físicas e químicas, por meio de análise elementar, caracterização de grupos funcionais (Espectroscopia de Infravermelho com Transformada de Fourier - FTIR), avaliação da morfologia das superfícies (Microscopia Eletrônica de Varredura - MEV), bem como, área superficial específica (ASEBET) e porosidade. Estudo cinético foi realizado, visando determinar o tempo de equilíbrio do processo de adsorção, bem como, o mecanismo cinético que controla o processo. Também foram modeladas isotermas de Langmuir e Freundlich. A determinação da atrazina, após os ensaios de adsorção, foi realizada por Cromatografia Líquida de Alta Performance (CLAE). As análises realizadas apontaram que a capacidade de adsorção dos biocarvões diminuiu na ordem de BE 450 > BE 350 > BE 550, e tal capacidade está associada às características físicas e químicas dos biocarvões. Os três biocarvões são bem representados pelo modelo cinético de pseudo-segunda ordem. Todos biocarvões exibiram elevada afinidade para a adsorção do herbicida atrazina, contudo, o biocarvão produzido à 450 ºC demonstra maior capacidade de adsorção

Une nouvelle méthode de détection sans marquage des interactions biomoléculaires a été développée. Elle est basée sur la conception d’une couche sensible supportée innovante réalisée par la technique de Langmuir‐Blodgett. Cette couche est composée d'un lipide à tête polaire immobilisant un cation métallique divalent capable (i) de chélater une molécule possédant une affinité pour ce type de cation et (ii) de catalyser la réaction de chimiluminescence du luminol. L'intensité du signal chimiluminescent est modulée par la présence de biomolécules fixées en surface de la couche sensible, qui modifient l'environnement immédiat du cation métallique. La variation du signal chimiluminescent (issu de la catalyse par le cation immobilisé) a pu être quantifiée et corrélée à une gamme de concentration d’histamine et d’anticorps. Les potentialités de cette approche ont finalement été exploitées pour développer une puce de PMMA de type macropuce immobilisant la monocouche de lipides. / A new label‐free detection method for biomolecular interactions was developed. It is based on the development of an original sensitive layer performed with the Langmuir‐ Blodgett technique. This layer is composed of a lipid which immobilized a bivalent metallic cation on his polar head, able (i) to chelate a molecule which has an affinity for this cation and (ii) to catalyze the luminol chemiluminescent reaction. The chemiluminescent signal intensity is modulated by the presence of immobilized biomolecules on the sensitive layer surface, which modifies the immediate environmentof the metallic cation. The chemiluminescent signal variation (from catalysis by the metallic cation) has been quantified and correlated to a histamine and antibody concentration range. The potentialities of this approach have finally been employed to achieve a PMMA chip (macroarray type), immobilizing the lipid monolayer.

Gegenstand der vorliegenden Arbeit ist die Entwicklung, Synthese und Charakterisierung neuartiger oligofunktionalisierter Amphiphile mit potentiellen Sammler- und LB-Filmbildungseigenschaften. Basierend auf dem entwickelten Konzept der supramolekularen Strukturbildung zum Aufbau präorganisierter und gebündelter Sammleraggregate wurden zwei Typen neuartiger oligofunktioneller Tenside synthetisiert, die sich insbesondere in ihrer konformativen Flexibilität und Hydrophilie-Lipophilie-Balance unterscheiden. Ausgeprägte oberflächenaktive Eigenschaften wurden bei den bi-, tri- und tetrafunktionellen Aminosäure-analogen Zielverbindungen (Typ II) mit linearer, trigonaler und tetragonaler Molekülstruktur gefunden. Diese Verbindungen bilden auch stabile monomolekulare Filme geringer Heterogenität aus. Im mineralischen Flotationsprozess ergeben diese präorganisierten Tenside mit geometrisch kontrollierter Positionierung der lateralen Funktionseinheiten im Vergleich zu konventionellen Sammlern bei spezifischem Verhalten eine bemerkenswerte Steigerung der flotativen Effizienz.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

El virus C (GBV-C) o virus de la hepatitis G (HGV) está relacionado con el virus de la hepatitis C (HCV) ya que tiene una organización genómica y una homología en la secuencia muy próxima pero, sin embargo, no parece causar hepatitis ni ningún otro tipo de patología. En los últimos años, se han publicado numerosos trabajos en los que se asocia la co-infección del GBV-C/HGV y el virus de la inmunodeficiencia humana (VIH) con una menor progresión de la enfermedad causada por el virus VIH así como con una mayor supervivencia de los pacientes una vez que el SIDA se ha desarrollado. Basándonos en un modelo de co-infección, existen diversas teorías de cómo el virus de la hepatitis G puede influir en la enfermedad del VIH, se cree que puede inducir las quemoquinas, regular negativamente los co-receptores del VIH, así como provocar otros efectos indefinidos en los linfocitos huésped. Pero el mecanismo responsable del efecto beneficioso que el GBV-C/HGV tiene sobre el curso de la infección causada por VIH no está todavía definido. Teniendo en cuenta el posible uso de los péptidos sintéticos, el objetivo de la actual tesis doctoral es llevar a cabo la selección de péptidos de la proteína de envoltura E1 del GBV-C/HGV con potencial capacidad de inhibición del péptido de fusión del VIH-1, mediante la síntesis múltiple en paralelo de secuencias peptídicas lineales que cubren la totalidad de la estructura primaria de esta proteína y su posterior evaluación mediante ensayos biofísicos. Con ello se pretende plantear la utilización de péptidos sintéticos del GBV-C/HGV en el diseño de inhibidores de la entrada del VIH en la célula huésped. Se pretende así tratar de comprender mejor el efecto de la presencia de anticuerpos anti-GBV-C/HGV en la progresión de la enfermedad causada por la infección del VIH y de profundizar en el conocimiento actual acerca de la interacción entre estos dos virus. Se realiza la síntesis en fase sólida de 58 péptidos correspondientes a la proteína de envoltura E1 del GBV-C/HGV y mediante el ensayo de liberación de contenidos vesiculares se seleccionan 5 péptidos capaces de inhibir la capacidad del péptido de fusión (PF) del VIH-1 de formar poros en las membranas. Se realizan estudios detallados de los péptidos y de la inhibición del proceso de fusión, inducido por el péptido de fusión del VIH-1, por parte de secuencias del GBV-C/HGV. Para ello se realizan estudios de citotoxicidad, ensayos de hemólisis, estudio de la estructura mediante dicroísmo circular, ensayos de agregación de liposomas inducida por los péptidos y ensayos de transferencia de energía por resonancia. Por otra parte se realizan ensayos utilizando monocapas de extensión como modelos de membrana mediante la técnica de Langmuir-Blodgett, y se calculan las concentraciones superficial de exceso y las de saturación, información que servirá para conocer la capacidad de los péptidos para formar monocapas estables en la interfase aire/agua. Los diferentes ensayos muestran una interacción de los péptidos de la proteína E1 con el péptido de fusión del VIH-1, dando lugar a una inhibición de la actividad que el péptido de fusión del VIH-1 tiene sobre las membranas lipídicas. Esto sugiere que estos péptidos pueden ser candidatos para ser utilizados en futuras terapias antivirales. / "BIOPHYSICAL STUDIES OF SYNTHETIC PEPTIDES OF THE ENVELOPE PROTEIN E1 OF GBV-C/HGV AND ITS RELATIONSHIP WITH HIV" The virus C (GBV-C) or hepatitis G virus (HGV) is related to hepatitis C virus (HCV) because it has similar genome organization and sequence homology; however, it does not seem to cause hepatitis or any other pathology. In recent years, there have been several studies in which the GBV-C/HGV and human immunodeficiency virus (HIV) co-infection is associated with less progression of the disease caused by HIV as well as improved survival of patients after AIDS has developed. Based on a model of co-infection, there are several theories of how the hepatitis G virus can affect HIV disease: it could induce chemokines, negatively regulate the HIV co-receptors and cause other undefined effects in the host cell. But the mechanism responsible for the beneficial effect that GBV-C/HGV has over the course of infection by HIV is not yet defined. Taking into account the possible use of synthetic peptides, the aim of the present thesis is to carry out the selection of peptides from the envelope protein E1 of GBV-C/HGV with potential ability to inhibit the HIV-1fusion peptide. The aim is to better understand the effect of the presence of antibodies anti-GBV-C/HGV in the progression of AIDS and to study the interaction between these two viruses. The solid phase synthesis of 58 peptides corresponding to the envelope protein E1 of GBV-C/HGV was made and 5 peptides capable of inhibiting the ability of the fusion peptide (FP) of HIV-1 to form pores in membranes were selected by means of the leakage of vesicular contents assay. Detailed studies of the E1 peptides and their ability to inhibit the fusion process induced by the fusion peptide of HIV-1 were done. Monolayers and liposomes were used as model membranes. The different tests show an interaction of the E1 peptides with the HIV-1fusion peptide, resulting in an inhibition of the activity that the fusion peptide has on lipid membranes. This suggests that these peptides could be good candidates for future antiviral therapies.

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No. of bitstreams: 1 maximino_md_me_prud.pdf: 5933036 bytes, checksum: 96040f746ca01578e5036f01f3d89e6e (MD5) Previous issue date: 2018-02-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O presente trabalho trata do estudo da interação entre os poluentes emergentes amoxicilina (AMX) e azul de metileno (AM) com modelos-simples de membrana biológica compostas de fosfolipídios zwiteriônicos (DPPC e DOPC), através de filmes de Langmuir e vesículas unilamelares gigantes (GUVs). As membranas foram expostas aos poluentes de forma individual e também misturados (MIX) para que se aproximasse de uma situação real, neste caso, o chamado efeito coquetel, no qual os poluentes são encontrados misturados no ambiente. O objetivo principal foi investigar as possíveis interações entre os poluentes e os fosfolipídios e os consequentes efeitos nas membranas. Nos filmes de Langmuir, as isotermas π-A (pressão superficial por área molecular média) de DPPC revelaram que a AMX e o AM são expulsos da interface ar-água conforme a fase condensada é atingida. O DOPC demonstrou ser menos afetado pela AMX, uma vez que a isoterma não apresentou deslocamento. Contudo, o DOPC se mostrou mais susceptível a interagir com o AM, visto que um deslocamento significativo foi observado. Para ambos os lipídios a MIX causou maiores efeitos, evidenciados por deslocamentos maiores nas isotermas. Análises de módulo compressional mostraram um pequeno aumento na fluidez do filme de DPPC, não observado para o DOPC. As medidas de microscopia de ângulo de Brewster (BAM) na presença dos poluentes revelaram mudanças na morfologia dos filmes, afetando a formação dos domínios de DPPC e impedindo a formação dos mesmos nas monocamadas de DOPC. Os espectros de PMIRRAS para o DPPC indicaram possíveis interações eletrostáticas dos poluentes com a cabeça polar do lipídio, assim como uma desordem na região da sua cauda apolar. A monocamada de DOPC foi bastante afetada pois ocorreram mudanças nas vibrações de quase todos os grupos químicos do lipídio, apresentando inclusive mudanças na região da cauda do lipídio. Os espectros de emissão da sonda LAURDAN nas LUVs revelaram um aumento da rigidez para ambos os lipídios, diferentemente do observado pelas análises de elasticidade da monocamada de Langmuir. As GUVs para ambos os fosfolipídios, ao contrário das monocamadas, apresentaram maior efeito sobre os poluentes aplicados de forma individual, visto que para os poluentes avaliados individualmente foram observados a perda de contraste de fase para os lipídios na presença do AM, assim como mudanças na estabilidade para as GUVs de DOPC em AMX. Tais efeitos não foram observados para a MIX, devido as diferenças estruturais dos modelos de membrana. / The present work is about the interaction between the emerging pollutants amoxicillin (AMX) and methylene blue (MB), with biological membrane models of zwitterionic phospholipids (DPPC and DOPC), through Langmuir films and giant unilamellar vesicles (GUVs). The membrane was exposed to the presence of the pollutants individually, still being performed the analysis with the mixture (MIX) of both in order to get closer to a real situation, in which the pollutants are found mixed in the environment. The main goal was to investigate the possible interactions between the pollutants and phospholipids. The π-A (surface pressure by mean molecular area) isotherms of DPPC reveal that in the condensed phase the lipid expelled the AMX and MB of the air-water interface. The DOPC showed to be less affected by the AMX, once the isotherm did not present a displacement. However, the DOPC showed to be more susceptible to interact with the MB, since significant displacements were observed. In both lipids, the MIX showed to be more effective, causing bigger displacements. The analysis of compressional modulus showed a small increase of the fluidity of the DPPC film, which was not observed to the DOPC. The Brewster Angle Microscopy (BAM) measurements in the presence of the pollutants revealed changes in the morphology, affecting the domains formation of DPPC and inhibiting the formation of the same in monolayers. The PM-IRRAS specters to the DPPC indicated possible electrostatic interactions with the head, as well as a disorder in the tail. The DOPC monolayer was quite affected because there have been changes in almost all chemical groups of lipid, including changes in the tail region of the lipid. The emission spectrum from the dye LAURDAN in the LUVs revealed an increase in the rigidity for both lipids, different from the observed in the analysis of elasticity in the Langmuir monolayers. The GUVs for both phospholipids, unlike the monolayers, showed a major effect on the pollutants applied individually since that were observed losses of phase contrast for the lipids in the presence of MB, such as changes in the stability of the DOPC GUVs in AMX. Such effects were not observed in the MIX, due to the structural differences in the membrane models.

Made available in DSpace on 2014-12-17T15:01:28Z (GMT). No. of bitstreams: 1 RicardoPFM_DISSERT.pdf: 809568 bytes, checksum: 0179539902298813dbee39bd2859650c (MD5) Previous issue date: 2012-07-20 / The generation of effluent from the finishing process in textile industry is a serious environmental problem and turned into an object of study in several scientific papers. Contamination with dyes and the presences of substances that are toxic to the environment characterize this difficult treatment effluent. Several processes have already been evaluated to remove and even degrade such pollutants are examples: coagulation-flocculation, biological treatment and advanced oxidative processes, but not yet sufficient to enable the recovery of dye or at least of the recovery agent. An alternative to this problem is the cloud point extraction that involves the application of nonionic surfactants at temperatures above the cloud point, making the water a weak solvent to the surfactant, providing the agglomeration of those molecules around the dyes molecules by affinity with the organic phase. After that, the formation of two phases occurred: the diluted one, poor in dye and surfactant, and the other one, coacervate, with higher concentrations of dye and surfactants than the other one. The later use of the coacervate as a dye and surfactant recycle shows the technical and economic viability of this process. In this paper, the cloud point extraction is used to remove the dye Reactive Blue from the water, using nonionic surfactant nonyl phenol with 9,5 etoxilations. The aim is to solubilize the dye molecules in surfactant, varying the concentration and temperature to study its effects. Evaluating the dye concentration in dilute phase after extraction, it is possible to analyze thermodynamic variables, build Langmuir isotherms, determine the behavior of the coacervate volume for a surfactant concentration and temperature, the distribution coefficient and the dye removal efficiency. The concentration of surfactant proved itself to be crucial to the success of the treatment. The results of removal efficiency reached values of 91,38%, 90,69%, 89,58%, 87,22% and 84,18% to temperatures of 65,0, 67,5, 70,0, 72,5 and 75,0?C, respectively, showing that the cloud point extraction is an efficient alternative for the treatment of wastewater containing Reactive Blue / A gera??o de efluente proveniente do processo de acabamento na industria t?xtil ? um grave problema ambiental e se transformou em objeto de estudo em diversos trabalhos cient?ficos. A contamina??o por corantes e a presen?a de subst?ncias que s?o t?xicas ao meio ambiente caracterizam este efluente de dif?cil tratamento. V?rios processos j? foram avaliados para remover e at? degradar tais poluentes s?o exemplos: a coagula??o-flocula??o, tratamento biol?gico e processos oxidativos avan?ados, mas ainda n?o foram suficientes para possibilitar a recupera??o do corante ou pelo menos do agente separador. Uma alternativa para este problema ? a extra??o por ponto nuvem que envolve a aplica??o de tensoativos n?o i?nicos a temperaturas acima do ponto de nuvem, tornando a ?gua um solvente fraco para o tensoativo, proporcionando a aglomera??o destas mol?culas ao redor do corante por afinidade a fase org?nica. Depois disso ocorre a forma??o de duas fases: uma chamada de dilu?da pobre em corante e tensoativo e a coacervato com concentra??o de corante e tensoativo bem maior que a outra fase. A utiliza??o posterior do coacervato como reciclo de corante e tensoativo mostra a viabilidade t?cnica e econ?mica do processo. Neste trabalho a extra??o por ponto nuvem ? utilizada para remover o corante Reactive Blue da ?gua utilizando tensoativo n?o-i?nico nonil fenol com 9,5 etoxila??es. O objetivo ? solubilizar as mol?culas de corante no tensoativo, variando-se a concentra??o deste e a temperatura para estudar seus efeitos. Avaliando a concentra??o de corante na fase dilu?da ap?s a extra??o ? poss?vel analisar vari?veis termodin?micas, construir isotermas de Langmuir, determinar o comportamento do volume de coacervato para uma concentra??o de tensoativo e temperatura, o coeficiente de distribui??o e a efici?ncia de remo??o de corante. A concentra??o de tensoativo mostrou-se fundamental para o sucesso do tratamento. Os resultados de efici?ncia de remo??o alcan?aram valores de 91,38%, 90,69%, 89,58%, 87,22% e 84,18% para temperaturas de 65,0, 67,5, 70,0, 72,5 e 75,0?C, respectivamente, mostrando que a extra??o por ponto nuvem ? uma alternativa eficiente para o tratamento de efluentes contendo Reactive Blue