Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-04-19T15:38:52Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese Sérgio Rocha para Defesa OK.pdf: 3444360 bytes, checksum: da9ca3f2c9d898e60430ef1b21bd681a (MD5) / Made available in DSpace on 2016-04-19T15:38:52Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese Sérgio Rocha para Defesa OK.pdf: 3444360 bytes, checksum: da9ca3f2c9d898e60430ef1b21bd681a (MD5) Previous issue date: 2015-02-25 / O infarto agudo do miocárdio (IAM) representa hoje um dos maiores problemas de saúde mundial prevalecendo sobre doenças como câncer, AIDS e doenças respiratórias. Em virtude da relevância, métodos cada vez mais eficientes para auxilio no diagnóstico do IAM vem sendo desenvolvidos. Um destes métodos, os aptassensores, chegam como ferramenta analítica alternativa para detecção de marcadores de necrose miocárdica. Neste trabalho um aptassensor simples e livre de marcação foi desenvolvido para detecção de troponina T cardíaca (cTnT), para isto, nanopartículas de prata foram sintetizadas eletroquimicamente sobre eletrodos impressos de tinta de carbono. Em seguida, 5 μL de cisteína foi adicionada à superfície sensora com intuito de servir de braço químico e possibilitar a imobilização do aptâmero. O aptâmero usado consiste em DNA fita simples modificado com grupos amino (NH2-ssDNA) e específico para o analito em questão. As condições ideais para imobilização do aptâmero e reconhecimento da molécula alvo, assim como a caracterização eletroquímica do aptassensor, foram investigados através das técnicas de voltametria cíclica (CV) e voltametria de pulso diferencial (DPV). A especificidade do aptassensor foi investigada utilizando para isso moléculas alvo específicas e inespecíficas. O reconhecimento do alvo apresentou alta sensibilidade com limite de detecção em 0,1 ng mL−1 de cTnT e uma boa reprodutibilidade (CV = 4%). O sensor também foi testado com amostras de soro humano, apresentando ótima concordância (95% de nível de confiança) com o padrão ouro, o método ECLIA. Neste trabalho pôde-se constatar que as nanopartículas de prata incorporadas a superfície eletródica melhoraram a reprodutibilidade, a condutividade e, consequentemente a resposta sensora, enquanto os aptâmeros asseguraram a sensibilidade e especificidade do aptasensor, apresentando, este modelo, grande potencial para uso no monitoramento dos níveis séricos de troponina cardíaca. / Acute myocardial infarction (AMI) it is one of the most serious diseases in the world responsible for approximately 17 million of deaths in 2012. Therefore, early diagnosis and prompt medical response are of paramount importance for patient survival. Aptasensors can be an alternative, which in combination with electrochemical techniques can provide the simplicity and speed required. A simple and sensitive label-free aptasensor for cardiac troponin T (cTnT) detection was successfully developed. For this purpose, it was chosen a DNA aptamers modified with amino group (NH2-ssDNA) specific to bind cTnT with a high specificity and stability. Herein, silver nanoparticles electrochemically synthesized and cysteine were used to modify the electrode, providing binding sites for aptamer immobilization. The optimum conditions for immobilization of the aptamer and target recognition were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) technique. The aptasensor achieved a low limit of detection (0.3 ng mL−1) and a linear range between 0.1 and 10 ng mL−1 cTnT, significant for acute myocardial infarction diagnosis. Good reproducibility was obtained by the proposed aptasensor supported by a coefficient of variation of 4%. The silver nanoparticles incorporated to the electrode surface improved the reproducibility, while the aptamer secured the sensitivity of the biosensor. The sensor was also tested for human serum samples presenting a good agreement with the ECLIA methods at 95% confident level. This point-of-care approach presents a great potential for use in several situations releasing the aptasensor for use in the cardiac troponin detection.

Orientador: Marcelo Bispo De Jesus / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-27T02:58:56Z (GMT). No. of bitstreams: 1 Ferreira_LuizAlbertoBandeira_M.pdf: 6087254 bytes, checksum: 800e7d6dd948a9f1da84d37dbff2a96d (MD5) Previous issue date: 2015 / Resumo: A nanomedicina se tornou uma promessa de profundos impactos para a saúde humana através da utilização de nanopartículas, nanorobôs e outros nanomateriais para prevenir, diagnosticar ou curar doenças. Um dos exemplos de nanomateriais empregados na medicina são as nanopartículas de prata, que podem ser adquiridas por métodos químicos ou biossintéticos. As nanopartículas de prata apresentam alta atividade antimicrobiana, propriedade essa de grande interesse científico-industrial. Em vista disso, cresce também a preocupação em relação ao uso, manipulação e eliminação desse nanomaterial, visando uma aplicação mais segura. Diante dessas informações, o presente trabalho teve como objetivo investigar mecanismos moleculares envolvidos na citotoxicidade e processamento das nanopartículas biossintéticas de prata em macrófagos peritoneais obtidos de camundongos C57BL/6. Inicialmemte, demonstrando que as nanopartículas atingiram o IC50 de 25 µM em 6h de tratamento por redução do MTT. A análise de microscopia de fluorescência revelou alterações na integridade de membrana a partir de 3 h, que foram agravadas após 6 h de tratamento. Esse mesmo perfil foi observado por microscopia eletrônica de varredura, no qual revelou que após 3 h de tratamento as células já apresentavam perda de projeções celulares, e após 6 h início de fragmentação celular. Além disso, as nanopartículas causaram aumento dos níveis de espécies reativas de oxigênio e demonstramos que este é um fator determinante para os efeitos citotóxicos. Com a inibição da fagocitose e endocitose mediada por caveolina evidenciamos a reversão parcial da citotoxicidade das nanopartículas. Por outro lado, o aumento do efeito citotóxico das nanopartículas também foi observado com a inibição da autofagia, o que sugere que esses processos estejam envolvidos no processamento das nanopartículas. Por fim, concluímos que as nanopartículas biossintéticas de prata apresentaram um efeito citotóxico semelhante aqueles descritos em literatura pelas nanopartículas de síntese química / Abstract: Nanomedicine became a promise of profound impacts on human health through the use of nanoparticles, nanorobots and other nanomaterials to prevent, diagnose or cure diseases. One example of nanomaterials used in medicine is silver nanoparticles, which can be produced by chemical or biosynthetic methods. Silver nanoparticles have high antimicrobial activity; this property is of great scientific and industrial interest. Consequently, there is growing concern about the use, handling and disposal of nanomaterials, aiming more secure application. Hence, the present study aimed to investigate the molecular mechanisms involved in cytotoxicity and intracellular processing of biogenic silver nanoparticles in peritoneal macrophages from C57BL/6 mice. We began showing that the nanoparticles have reached the IC50 of 25 µM after 6 hours of treatment determined by MTT reduction. Fluorescence microscopy analysis showed changes in membrane integrity after 3 h, which has been intensified after 6 h of treatment. A similar profile was observed by scanning electron microscopy, which showed loss of cellular projections after 3 h of treatment and after 6 h was observed cellular fragmentation. In addition, the nanoparticles treatment increased levels of reactive oxygen species and this response seems to be determining for the cytotoxic effects. The inhibition of phagocytosis and caveolin-mediated endocytosis led to a reduction in cytotoxicity of nanoparticles. On the other hand, an increase in the cytotoxic effect was observed upon inhibition of autophagy, suggesting that this response is part of the intracellular processing of the nanoparticles in peritoneal macrophage. Finally, we concluded that the biogenic of silver nanoparticles exhibited cytotoxic effects similar to that described for silver nanoparticles chemically synthesized / Mestrado / Fármacos, Medicamentos e Insumos para Saúde / Mestre em Ciências

Orientadores: Francisco das Chagas Marques, Carlos Lenz César / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-29T22:06:44Z (GMT). No. of bitstreams: 1 VillegasBorrero_NelsonFabian_M.pdf: 7427305 bytes, checksum: 95d120bd4cca81a54f7e8af57dfd2ab5 (MD5) Previous issue date: 2015 / Resumo: Neste trabalho foram fabricadas nanopartículas metálicas de prata (NPsM de Ag) em soluções coloidais usando a técnica de ablação à laser. Parâmetros como o comprimento de onda do laser, energia do pulso e a taxa de repetição afetam a distribuição de tamanho das NPsM. Assim, neste trabalho estudamos a influência destes parâmetros sobre o tamanho das NPsM de Ag. Para isto foi feita uma montagem experimantal na qual um alvo de prata é imerso em um líquido e irradiado por um pulso de laser de Nd:YAG para criar soluções coloidais. Foi encontrada uma variação dos picos de absorção entre = 394nm e = 405nm. Segundo a previsão da teoria de Gustav Mie, as variações nos picos tem a ver com a variação na distribuição de tamanhos. Para comprovar estes resultados foi feita uma estimativa do tamanho médio das NPsM de Ag usando a análise de imagens tomadas com o Microscópio Eletrônico de Varredura (MEV) e a técnica de Espalhamento Dinâmico da Luz (DLS). O espectro experimental e a teoria de Gustav Mie (simulação feita usando o software mathematica) encontram-se em concordância. As NPsM produzidas foram usadas para medir o efeito de aumento no sinal Raman em superfícies (SERS) encontrando-se que o sinal do espalhamento Raman de corantes usados em diferentes pesquisas (Rodâmina B e N719) aumenta com o uso das NPsM / Abstract: In this work we fabricated silver nanoparticles (Ag NPs) in colloidal solutions with specific sizes. Parameters like laser wavelength, pulse energy and pulse repetition rate affect the distribution of NPs size. In this work we studied the influence of these parameters on the size of Ag NPs. For that purpose we mount a set-up in which a silver target was immersed in liquid and irradiated by Nd:YAG pulsed laser to create different colloids. We found that the absorption peak of these colloids lays between 394nm and 405nm. We estimated a mean size of Ag NPs from images taken by Scanning Electron Microscope (SEM) and Dynamic Ligth Scattering (DLS). The calculated absorption spectra and simulation through Gustav Mie theory (Simulated in Matthemathica software) were in good agreement. The produced NPs were used in Enhacement Raman Spectroscopy (SERS) measurements, finding that the signal of Rhodamina B and N719 Dyes increases using these NPsM / Mestrado / Física / Mestre em Física / 1247650/2013 / CAPES

Orientador: César Renato Foschini / Resumo: O óxido de zinco (ZnO) apresenta uma grande versatilidade física, elétrica, mecânica e propriedades químicas que podem ser exploradas em uma variedade de aplicações, tais como fotocatálise, nanoadsorventes e sensoriamento de gases. Os materiais nanoestruturados têm atraído a atenção da ciência e tecnologia nos últimos anos porque podem melhorar suas propriedades em nanoescala. A prata em escala nanométrica tem gerado interesse de pesquisadores de diferentes áreas, pois a prata é moldável e maleável, possui elevada condutividade térmica e elétrica, além de ser um forte oxidante. Neste trabalho, foram desenvolvidos filmes de óxido de zinco puro e dopados com nanopartículas de prata, visando aplicação em sensores de gás. Os filmes de óxido de zinco foram fabricados pelo método dos precursores poliméricos e utilizados como matriz devido a sua interatividade com os gases. As nanopartículas de prata foram produzidas por meio de reação em emulsão, explorando sua alta condutividade elétrica. Dessa forma, por meio das propriedades de ambos os materiais, desenvolveu-se um sensor de gás composto de óxido de zinco na forma de filmes em substratos de Al2O3, com diferentes camadas dopadas e não dopadas com nanopartículas de prata. Notou-se que o desenvolvimento de um material compósito do tipo filme de ZnO dopado com as nanopartículas de prata, apresentou propriedades melhoradas, como por exemplo, a resposta elétrica do material quando comparada com o filme contendo apenas o filme de ZnO p... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Zinc oxide (ZnO) presents a great physical, electrical, mechanical and chemical versatility that can be exploited in a variety of applications, such as photocatalysis, nanoadsorbents and gas sensing. Nanostructured materials have attracted the attention of science and technology in recent years because they can improve their nanoscale properties. The silver in nanoscale has generated interest of researchers of different areas, because the silver is moldable and malleable, has high thermal and electrical conductivity, besides being a strong oxidant. And this project was developed based on the production of silver nanoparticles and zinc oxide films for the application in gas sensors. The zinc oxide films were manufactured by the method of the polymeric precursors and used as matrix due to its interactivity with the gases. The silver nanoparticles were produced by means of emulsion reaction, exploring their high electrical conductivity. Thus, through the properties of both materials, a gas sensor composed of zinc oxide in the form of films on substrates of Al2O3, with different layers doped and not doped with silver nanoparticles was developed. It was noted that the development of a ZnO film-like composite material doped with the silver nanoparticles exhibited improved properties, such as the electrical response of the material as compared to the film containing only the pure ZnO film. / Mestre

MESHWR / Department of Hydrology and Water Resources / Water borne diseases due to inadequate and unsafe drinking water is a global challenge that has led to a significant number of deaths and illnesses reported annually. These diseases are prevalent in less-developed countries, especially in rural areas where there is shortage of basic infrastructure and inadequate funds for piped water systems in individual households. Community members are forced to resort to collecting water from communal water points and later storing the water in containers for daily use. Recontamination of microbiologically safe drinking water during and after collection from the water source has been recognised as a problem; hence treating water at household level is one way to provide potable water for affected communities. The microbiological quality of household water may be improved by using point-of-use treatment technologies such as chemical disinfection, solar disinfection and ceramic water filters. Some of these technologies are expensive, less effective and difficult to implement in rural communities. This research thus focused on ceramic water filters and finding an appropriate method for silver application so as to produce filters that are effective in both the provision of clean drinking water and the release of silver levels that are safe for human consumption. An assessment of the efficiency of ceramic water filters made with silver nitrate as point-of -use water treatment device in Dertig Village, North West Province, South Africa was carried out. During production of filters made with silver nitrate, the filters undergo firing in an electric kiln and ionic silver is reduced to metallic nanopatches dispersed throughout the porous ceramic media. Both filters made with silver nitrate and conventional silver nanoparticles impregnated ceramic water filters were manufactured at the PureMadi Dertig Ceramic Filter Facility, South Africa. Resulting filters were evaluated and quantified for total coliform and E. coli removal as well as silver concentration in the effluent. Ceramic water filters made with silver nitrate had a high removal efficiency for total coliforms (94.7%) and E. coli (99.3%). A comparison of the performance of filters made with silver nitrate and silver nanoparticles in the provision of potable water was carried out and results showed that the different filters had similar levels of total coliform and E. coli removal, although the silver nitrate filters produced the highest average removal of 97.23% while silver nanoparticles filters produced the lowest average removal of 85.43%. Reasonable silver levels were obtained in effluent from all filters. Average effluent silver levels were 0.07±0.04mg/L, 0.6±1.10 mg/L and 0.8±1.0mg/L for 1 g, 2 g and silver nanoparticle filters, respectively (below the EPA and WHO standard of 100 mg/L). Because silver nitrate filters resulted in the lowest effluent silver concentrations, this could potentially increase the effective life span of the filter. A cost analysis of the process proved that it was cheaper to produce ceramic water filters using silver nitrate as the chemical can be purchased locally and also eliminates labour related costs. Thus, filters made using silver nitrate could potentially improve performance, reduce production costs, and increase safety of production for workers. The results obtained from this study will be applied to improve the ceramic filtration technology as point-of-use water treatment device in an effort to reduce health problems associated with microbial contamination of water stored at household level. / NRF

Des nanocomposites polyuréthane-argent (PU-Ag) ont été élaborés à l'aide de deux procédés respectueux de l'environnement et du manipulateur, dans le but de prévenir la colonisation microbienne de ces matériaux. Le premier consiste à incorporer une dispersion aqueuse de nanoparticules d'argent, réalisée ex situ, au cours du procédé de synthèse d'un PU en dispersion aqueuse. Une dispersion de nanoparticules d'argent obtenue par réduction chimique, sous micro-ondes, d'ions d'argent en présence de polyéthylèneglycol a été développée dans l'objectif d'intégrer chimiquement le PEG dans les chaînes de PU. Le second procédé réside dans la réduction photochimique, in situ, d'ions argent dans une matrice PU, en l'absence de tout autre composé chimique.La caractérisation des matériaux obtenus montre une dispersion homogène des nanoparticules d'argent avec des tailles de particules faibles (5 à 50 nm] et une activité biocide des surfaces vis-à-vis de deux souches bactériennes (Pseudomonas aeruginosa et Enterococcus faecalis) sans modification notable des propriétés physicochimiques intrinsèques du PU. / Two environment and human-friendly processes were developed to synthesize polyurethane-silver (PU-Ag) nanocomposites having biocide surfaces able preventing the microbial colonization.The first one, called ex-situ process, consists in incorporating a silver nanoparticles aqueous dispersion during the synthesis process of polyurethane, which is itself carried out in aqueous dispersion. In this case, the chemical reduction of silver ions under microwaves and in the presence of polyethyleneglycol was particularly developed with the aim to chemically incorporate the PEG in the PUchains. For the second process, silver ions dispersed inside a PU matrix were photochemically reduced in situ.The obtained materials exhibit a homogeneous dispersion of silver nanoparticles with small diameter (from 5 to 50 nm) without marked modification of the intrisic physomchemical properties of the PU. Lastly, the antibacterial properties of the surfaces aginst Pseudomonas aeruginosa and Enterococcus faecalis were confirmed.

Gels are a special class of materials which are composed of 3D networks of crosslinked polymer chains that encapsulate liquid/air in the matrix. They can be classified into organogels or hydrogels (organic solvent for organogel and water for hydrogel). For hydrogels that contain metallic elements in the form of ions, the term of metallo-supramolecular polymer hydrogel (MSPHG) is often used. The aim of this project is to develop a kind of new MSPHG and investigate its properties and possible applications. The commercial polymeric anhydride poly(methyl vinyl ether-alt-maleic anhydride) (PVM/MA) is converted by reaction with NaOH to give poly(methyl vinyl ether-alt-monosodium maleate) (PVM/Na-MA). By addition of AgNO3-solution, the formation of the silver(I) supramolecular polymer hydrogel poly[methyl vinyl ether-alt-mono-sodium maleate]∙AgNO3 is obtained. Freeze-dried samples of the hydrogel show a mesoporous network of polycarboxylate ligands that are crosslinked by silver(I) cations. The supercritical CO2 dried silver(I) hydrogel was characterized by FT-IR, SEM-EDAX, TEM, TGA and Physical adsorption (BET) measurements. The intact silver(I) hydrogel was characterized by cryo-SEM. In the intact hydrogel, ion-exchange studies are reported and it is shown that Ag+ ions can be exchanged by copper(II) cations without disintegration of the hydrogel. The silver(I) hydrogel shows effective antibacterial activity and potential application as burn wound dressing.

Dans le cadre du Traité d’Interdiction Complète des Essais nucléaires, le Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA) développe des systèmes de détection des essais nucléaires en se basant sur la mesure des isotopes radioactifs du xénon, tels que le Système de Prélèvement d’Air en Ligne avec l’Analyse des radioXénons. L’adsorption est un procédé adapté pour ce type d’applications mais nécessite l’utilisation de matériaux adsorbants très performants pour piéger et séparer les gaz rares d’intérêt présents dans l’air à l’état de traces. Ce travail doctoral a tout d’abord permis de poser un cadre méthodologique permettant de comparer les matériaux adsorbants disponibles pour séparer le xénon aux faibles pressions partielles et de sélectionner la zéolithe Ag@ZSM-5. De nombreuses techniques ont été employées dont la microscopie électronique à transmission et la simulation ab initio afin d’étudier le vieillissement de ce matériau en conditions procédés, lié aux étapes d’élution en température et aux conditions environnementales, et d’approfondir la connaissance de cet adsorbant. L’influence du support zéolithique sur la formation et la stabilité des particules métalliques, ainsi que l’interaction entre les nanoparticules et le xénon ont en effet été investigués. Finalement la zéolithe Ag@ZSM-5 a été mise en application dans un pilote de laboratoire automatisé. Ce procédé compact de séparation des gaz rares basé uniquement sur des étapes d’adsorption présente des performances encourageantes et permet d’envisager l’utilisation de ce matériau dans des applications variées, de la dépollution de l’air en radon jusqu’à la production industrielle de xénon / In the context of the Comprehensive Nuclear Test Ban Treaty, the Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA) is developing systems to detect nuclear tests based on the xenon radioactive isotopes measurement, such as the Système de Prélèvement d’Air en Ligne avec l’Analyse des radioXénons. Adsorption is a suitable process for this type of application but requires the use of high performance adsorbent materials to trap and separate the rare gases of interest present in the air in trace amounts.In the first instance, this PhD thesis has set a methodological framework to compare the adsorbent materials available to separate xenon at low partial pressures and to select the Ag@ZSM-5 zeolite. Numerous techniques ranging from transmission electron microscopy to ab initio calculation have been employed to study the aging of this material under process conditions, related to the thermal elution steps and environmental conditions. The knowledge of the material has been deepened by studying the influence of zeolite support on the formation and stability of metal particles, as well as the interaction between nanoparticles and xenon. Finally, the Ag@ZSM-5 zeolite was applied in an automated pilot. This compact process for the separation of noble gases based only on adsorption steps shows encouraging performances and allow considering the use of this material in various applications, ranging from decontamination of air polluted by radon to the industrial production of xenon

Silver nanoparticles (AgNPs) are the most common nanomaterials incorporated in commercial products due to their antimicrobial activity. Recently, AgNPs were detected in surface waters suggesting the potential for bioavailability in the aquatic receptor organisms. This dissertation research attempts to understand the potential toxicity of AgNPs on water quality indicators, focusing on the microbial community and amphipods. This study evaluated whether: (1) the antimicrobial properties of AgNPs pose potential risks to microbial communities in pathogen impaired streams; (2) AgNPs can cause a shift in functional diversity and metabolic fingerprinting of microbial communities; (3) survival and growth of Hyalella azteca (amphipods) could be affected by AgNPs; and (4) surface coating agents influence AgNP toxicity in H. azteca. Microbial community responses to AgNPs were assessed using standard plate count, microbial enzyme assays, and carbon substrate utilization with Biolog EcoPlates™. Ten-day and 28-d toxicity tests were conducted in a static system to assess AgNP effects on H. azteca. AgNPs caused a 69% decrease in microbial concentration and a 77% decrease in β-glucosidase activity at 0.32 mg Ag kg-1 dry sediment. The substrate utilization pattern of the microbial community was altered by AgNPs at 0.33 mg Ag kg-1 dry sediment. Ten-day LC50s for the survival of H. azteca were 3.3, 9.2, and 230.0 µg Ag L-1 for AgNO3, citrate-AgNP, and PVP-AgNP, respectively, whereas the 28-d LC50s were 3.0, 3.5, and 66.0 µg Ag L-1 for AgNO3, citrate-AgNP, and PVP-AgNP, respectively. The EC20s for growth (calculated as biomass) for the 10-d test were 1.6, 4.7, and 188.1 µg Ag L-1 for AgNO3, citrate-AgNP, and PVP-AgNPs; while the 28-d EC20s for AgNO3, citrate-AgNP and PVP-AgNP were 3.2, 0.5, and < 50 µg Ag L-1. The NOECS for dry weight were 4 and 1, and 100 µg Ag L-1, while those for biomass were 2, 0.5, and < 50 µg Ag L-1 for AgNO3, citrate-AgNP, and PVP-AgNP, respectively. The overall toxicity followed the trend: AgNO3 > citrate-AgNP > PVP-AgNP. The studies suggest that AgNPs pose potential risks to microbial communities and epibenthic macroinvertebrates used as bioindicators of water quality to protect public health and ecosystem health.

No description available.