Os desafios atuais no desenvolvimento de biossensores abrangem diversos aspectos, tais como a necessidade de se aperfeiçoar a interface de contato entre o substrato e o material biológico, a eficiência de transdução do sinal químico em um sinal mensurável, o tempo de resposta, a compatibilidade dos biossensores com matrizes biológicas e a integração de diferentes elementos de reconhecimento biológico em um único dispositivo, visando a detecção de distintos analitos. Nesse contexto, o desenvolvimento da nanociência tem criado recursos bastante atraentes para otimizar os aspectos descritos acima. O presente trabalho apresenta, portanto, estudos realizados para a construção de mediadores nanoestruturados que possam operar de maneira mais eficiente que os correspondentes materiais maciços (sistemas não-nanoestruturados). Em uma das abordagens utilizadas, um mediador híbrido de hexacianoferrato de cobre/polipirrol (CuHCNFe/Ppy) teve suas propriedades eletroquímicas aliadas às propriedades morfológicas e eletrônicas de um feltro revestido com nanotubos de carbono do tipo \"cup-stacked\" (feltro/NTCCS) para o desenvolvimento de um sensor de H2O2. O feltro/NTCCS é uma malha hidrofílica condutora que permite uma dispersão bastante uniforme do mediador híbrido. Essa característica, aliada ao aumento da área eletroativa e à interação eletrônica existente entre o CuHCNFe/PPy e os nanotubos de carbono criaram uma plataforma favorável para a construção de um biossensor de glicose. Em uma segunda estratégia, esferas de poliestireno com diâmetros de 300, 460, 600 e 800 nm foram utilizadas como molde para a formação de filmes de CuHCNFe/PPy macroporosos. Os distintos mediadores foram aplicados na detecção de H2O2 com o intuito de se correlacionar a importância do tamanho do poro com o desempenho analítico obtido. Diferentemente do esperado, os mediadores maciços e porosos apresentaram desempenhos analíticos bastante similares, o que levou a uma consideração das propriedades termodinâmicas de superfícies curvas, da molhabilidade de materiais porosos e da influência da cinética eletroquímica na utilização de sistemas porosos. Tais plataformas também foram aplicadas com sucesso na construção de biossensores de glicose e de colina. Por fim, foi possível sintetizar mediadores nanoestruturados através da imobilização de camadas de azul da Prússia e de CuHCNFe dentro das cavidades de filmes de TiO2 mesoporosos (13, 20 e 40 nm de diâmetro). Os resultados obtidos demonstraram a possibilidade de se modular o desempenho dos sensores de H2O2 em função do diâmetro dos poros e da quantidade de mediador imobilizado. A união dos resultados analíticos obtidos com os dados de microscopia eletrônica de varredura possibilitou observar a importância do efeito de confinamento no desempenho dos mediadores. Além disso, dados espectroscópicos na região do visível foram fundamentais para relacionar a presença de defeitos estruturais com a reatividade do material. No fim, tais plataformas foram utilizadas para a formulação de biossensores de colina. / Nowadays, the challenges in the development of biosensors cover various aspects such as the need to improve the interface between the substrate and the biological material, the efficiency of the chemical signal transduction in a measurable one, the response time, the compatibility with biological matrices and the integration of different biological recognition elements in a single device, in order to perform detections of different analytes. In this context, the development of nanoscience has created very attractive features to optimize the aspects described above. Consequently, the present work studies the build up of nanostructured transducers that can operate more efficiently than the corresponding bulk materials (systems non-nanostructured). In one of the approaches used, a hybrid transducer consisting of copper hexacyanoferrate/polypyrrole (CuHCNFe/Ppy) had its electrochemical properties combined with the morphological and electronic properties of a felt decorated with cup-stacked type carbon nanotubes (felt/CSCNT) for development of a H2O2 sensor. Felt/CSCNT is a hydrophilic conductive mesh that allows a uniform dispersion of the hybrid transducer. This feature, coupled with the improvement of electroactive surface and with the electronic interaction among the CuHCNFe/Ppy and carbon nanotubes have created a favorable platform for the construction of a glucose biosensor. In a second strategy, polystyrene spheres with diameters of 300, 460, 600 and 800 nm were used as templates for the formation of macroporous CuHCNFe/Ppy films. The transducers were used to detect H2O2 in order to correlate the importance of pore size with the obtained analytical performance. Unlike expected, porous and bulk transducers presented very similar analytical performances, which led to a consideration of the thermodynamic properties of curved surfaces, the wettability of porous materials and the influence of electrochemical kinetics during the use of porous systems. Such platforms have also been successfully applied in the preparation of glucose and choline biosensors. Finally, it was possible to synthesize nanostructured transducers through the immobilization of Prussian blue layers and CuHCNFe inside the cavities of mesoporous TiO2 films (pore diameters of 13, 20 and 40 nm). The obtained results demonstrated the possibility of modulating the performance of H2O2 sensors according to the pore diameter and the amount of immobilized transducer. The union of the obtained analytical results with scanning electron microscopy data showed the importance of confinement effect on the transducers performances. In addition, spectroscopic data in the visible region were essential to correlate the presence of structural defects with the material reactivity. In the end, these platforms were used for the formulation of choline biosensors.

Cette thèse porte sur le développement d'un traducteur ultrasonore multi-élément capacitif à couplage air (MEACUT) et son utilisation dans le domaine du contrôle non destructif (CND) de matériaux. Un modèle est employé pour simuler numériquement ce traducteur, et pour optimiser sa conception. Un prototype est ensuite fabriqué, puis caractérisé expérimentalement pour quantifier ses performances. Son originalité réside dans le fait qu'il possède une large bande passante en fréquence, tout en offrant la possibilité d'une focalisation variable. Ce prototype est alors employé pour la détection d'un endommagement causé par impact, dans une plaque composite. Il est clairement constaté que la résolution spatiale du procédé d'inspection employé (C-scan) est fortement améliorée grâce aux performances techniques du MEACUT. Enfin, un modèle hybride 3D est développé pour simuler, rapidement et intégralement, ce procédé de CND. Le très bon accord obtenu entre prédictions numériques et mesures expérimentales laisse présager que cet outil de simulation pourra servir à mettre au point d'autres expérimentations de CND, qui pourront à leur tour exploiter les performances du MEACUT. / This thesis focuses on the development of a Multi-Element Air-coupled Capacitive Ultrasonic Transducer (MEACUT) and its use in the field of non-destructive testing (NDT) of materials. A numerical model is used to simulate the translator, and to optimize its design. A prototype is then built and experimentally characterized to quantify its performance. Its originality lies in the fact that it has a broad frequency bandwidth while offering the possibility of a dynamic focusing. This prototype is then used for the detection of damage caused by impact, in a composite plate. It is clearly found that the spatial resolution of the inspection process employed (C-scan) is greatly improved thanks to the technical performance MEACUT. Finally, a 3D hybrid model is developed to simulate quickly and fully, the process of NDT. The good agreement obtained between numerical predictions and experimental measurements suggests that this simulation tool can be used to develop other NDT experiments, which may in turn exploit the performance of MEACUT.

De nouvelles applications émergent avec le développement de l’électronique souple comme des panneaux tactiles pliables, ou des capteurs de mouvement humain portables (wearable). Les technologies bien maîtrisées des jauges silicium sont mal adaptées à ces usages (faible élongation maximale, hautes températures de fabrication). Dans ce contexte, il est nécessaire de développer de nouveaux types de jauges. De nombreuses alternatives sont étudiées, qu’on peut diviser en deux catégories principales : les transducteurs nanoscopiques et les transducteurs composites. Dans ce travail, on étudie la possibilité d’utiliser une jonction tunnel MIM (Métal Isolant Métal) comme jauge de contrainte. Ce genre de dispositif est très peu étudié dans la littérature et la structure utilisée est généralement de type MIS (Métal Isolant Semi-conducteur). À chaque fois, la sensibilité du dispositif est expliquée par les propriétés du semi-conducteur (silicium). Les objectifs de cette thèse sont donc la compréhension des propriétés piézorésistives des jonctions MIM, l’optimisation de leur sensibilité et la fabrication d’un démonstrateur exploitant les technologies de la plastronique. Des jonctions de différentes natures (électrodes de différents métaux) sont fabriquées par évaporation et par ALD (Atomic Layer Deposition). La variation du courant en fonction de la contrainte est mesurée grâce à un banc de flexion. Le facteur de jauge associé est indépendant de la nature des électrodes mais varie fortement (de 40 à 75) en fonction du sens de polarisation de la jonction. Le facteur de jauge associé à la variation sous contrainte des paramètres géométriques (épaisseur et surface) est calculé mais reste inférieur à 13. Les phénomènes géométriques ne peuvent donc pas expliquer la sensibilité observée. L’étude de l’équation du courant Fowler Nordheim (identifié comme courant dominant dans nos jonctions) montre que cette sensibilité doit être associée à la variation sous contrainte de la hauteur de barrière aux interfaces métal/isolant, et/ou de la masse effective des électrons dans l’alumine. Des mesures de photoémission sont réalisées pour mesurer la hauteur de barrière des jonctions. À terme, cette méthode pourrait permettre de mesurer la variation sous contrainte, et donc de comprendre pleinement l’origine de la sensibilité des jonctions MIM. Pour finir, un démonstrateur intégrant des jauges MIM à effet tunnel (capteur de pression) est réalisé avec un substrat souple en polyimide rigidifié par une structure imprimée en 3D. Ce dispositif démontre la compatibilité des méthodes de fabrication des MIM avec les technologies souples et plastiques. / New applications are emerging with de development of flexible electronic like flexible touch panels and wearable movement sensors. The well mastered silicon technologies are ill adapted to these uses (low maximal elongation, high fabrication temperatures). In this context, it is necessary to develop new types of strain gauges. Numerous possibilities have been studied that can be divided in two main categories: nanosomic transducers and composite transducers. In this work, we study the possibility to use a MIM (Metal Insulator Metal) tunnel junction as strain gauge. This kind of structure is very unusual in the literature were the only similar article are based on MIS (Metal Insulator Semiconductor) junctions. The objectives of this thesis are thus the understanding of the piezorisistive properties of MIM structures, the optimisation of their sensitivity, and the realisation of a sensor prototype exploiting plastonic technologies.

Doctor of Philosophy (PhD) / With improvements in actuation technology and sensory systems, it is becoming increasingly feasible to create powered exoskeletal garments that can assist with the movement of human limbs. This class of robotics referred to as human-machine interfaces will one day be used for the rehabilitation of paralysed, damaged or weak upper and lower extremities. The focus of this project was the development of an exoskeletal interface for the rehabilitation of the hands. A novel sensor was designed for use in such a device. The sensor uses simple optical mechanisms centred on a spring to measure force and position simultaneously. In addition, the sensor introduces an elastic element between the actuator and its corresponding hand joint. This will allow series elastic actuation (SEA) to improve control and safely of the system. The Hand Rehabilitation Device requires multiple actuators. To stay within volume and weight constraints, it is therefore imperative to reduce the size, mass and efficiency of each actuator without losing power. A method was devised that allows small efficient actuating subunits to work together and produce a combined collective output. This work summation method was successfully implemented with Shape Memory Alloy (SMA) based actuators. The actuation, sensory, control system and human-machine interface concepts proposed were evaluated together using a single-joint electromechanical harness. This experimental setup was used with volunteer subjects to assess the potentials of a full-hand device to be used for therapy, assessment and function of the hand. The Rehabilitation Glove aims to bring significant new benefits for improving hand function, an important aspect of human independence. Furthermore, the developments in this project may one day be used for other parts of the body helping bring human-machine interface technology into the fields of rehabilitation and therapy.

Non-destructive testing (NDT) techniques are critical to ensure integrity and safety of engineered structures. Structural health monitoring (SHM) is considered as the next step in the field enabling continuous monitoring of structures. The first part of the thesis concerns NDT and SHM using guided waves in plates, or Lamb waves, to perform imaging of plate structures. The imaging is performed using a fixed active array setup covering a larger area of a plate. Current methods are based on conventional beamforming techniques that do not efficiently exploit the available data from the small arrays used for the purpose. In this thesis an adaptive signal processing approach based on the minimum variance distortionless response (MVDR) method is proposed to mitigate issues related to guided waves, such as dispersion and the presence of multiple propagating modes. Other benefits of the method include a significant increase in resolution. Simulation and experimental results show that the method outperforms current standard processing techniques. The second part of the thesis addresses transducer design issues for resonant ultrasound inspections. Resonant ultrasound methods utilize the shape and frequency of the object's natural modes of vibration to detect anomalies. The method considered in the thesis uses transducers that are acoustically coupled to the inspected structures. Changes in the transducer's electrical impedance are used to detect defects. The sensitivity that can be expected from such a setup is shown to highly depend on the transducer resonance frequency, as well as the working frequency of the instrument. Through simulations and a theoretical argumentation, optimal conditions to achieve high sensitivity are given.

Automatic translation has seen tremendous progress in recent years, mainly thanks to statistical methods applied to large parallel corpora. Transductions represent a principled approach to modeling translation, but existing transduction classes are either not expressive enough to capture structural regularities between natural languages or too complex to support efficient statistical induction on a large scale. A common approach is to severely prune search over a relatively unrestricted space of transduction grammars. These restrictions are often applied at different stages in a pipeline, with the obvious drawback of committing to irrevocable decisions that should not have been made. In this thesis we will instead restrict the space of transduction grammars to a space that is less expressive, but can be efficiently searched. First, the class of linear transductions is defined and characterized. They are generated by linear transduction grammars, which represent the natural bilingual case of linear grammars, as well as the natural linear case of inversion transduction grammars (and higher order syntax-directed transduction grammars). They are recognized by zipper finite-state transducers, which are equivalent to finite-state automata with four tapes. By allowing this extra dimensionality, linear transductions can represent alignments that finite-state transductions cannot, and by keeping the mechanism free of auxiliary storage, they become much more efficient than inversion transductions. Secondly, we present an algorithm for parsing with linear transduction grammars that allows pruning. The pruning scheme imposes no restrictions a priori, but guides the search to potentially interesting parts of the search space in an informed and dynamic way. Being able to parse efficiently allows learning of stochastic linear transduction grammars through expectation maximization. All the above work would be for naught if linear transductions were too poor a reflection of the actual transduction between natural languages. We test this empirically by building systems based on the alignments imposed by the learned grammars. The conclusion is that stochastic linear inversion transduction grammars learned from observed data stand up well to the state of the art.

Doctor of Philosophy (PhD) / With improvements in actuation technology and sensory systems, it is becoming increasingly feasible to create powered exoskeletal garments that can assist with the movement of human limbs. This class of robotics referred to as human-machine interfaces will one day be used for the rehabilitation of paralysed, damaged or weak upper and lower extremities. The focus of this project was the development of an exoskeletal interface for the rehabilitation of the hands. A novel sensor was designed for use in such a device. The sensor uses simple optical mechanisms centred on a spring to measure force and position simultaneously. In addition, the sensor introduces an elastic element between the actuator and its corresponding hand joint. This will allow series elastic actuation (SEA) to improve control and safely of the system. The Hand Rehabilitation Device requires multiple actuators. To stay within volume and weight constraints, it is therefore imperative to reduce the size, mass and efficiency of each actuator without losing power. A method was devised that allows small efficient actuating subunits to work together and produce a combined collective output. This work summation method was successfully implemented with Shape Memory Alloy (SMA) based actuators. The actuation, sensory, control system and human-machine interface concepts proposed were evaluated together using a single-joint electromechanical harness. This experimental setup was used with volunteer subjects to assess the potentials of a full-hand device to be used for therapy, assessment and function of the hand. The Rehabilitation Glove aims to bring significant new benefits for improving hand function, an important aspect of human independence. Furthermore, the developments in this project may one day be used for other parts of the body helping bring human-machine interface technology into the fields of rehabilitation and therapy.

Receiver systems utilising planar technologies are prevalent in telescopes observing at radio to sub-millimetre wavelengths. Receiver components using planar technologies are generally smaller, have reduced mass and are cheaper to manufacture than waveguide-based alternatives. Given that modern-day detectors are capable of reaching the fundamental photon noise limit, increases in the sensitivity of telescopes are frequently attained by increasing the total number of detectors in the receivers. The development of components utilising planar technologies facilitates the demand for large numbers of detectors, whilst minimising the size, mass and manufacturing cost of the receiver. After a review and study of existing concepts in radio to sub-mm telescopes and their receivers, this thesis develops planar components that couple the radiation from the telescope's optics onto the focal plane. Two components are developed; a W- band (75-110 GHz) planar antenna-coupled flat mesh lens designed for the receiver of a Cosmic Microwave Background (CMB) B-mode experiment, and an L-band (1- 2 GHz) horn-coupled planar orthomode transducer designed for the receiver of the FAST telescope. The first developments of a planar antenna-coupled flat mesh lens are presented. The design is driven by the requirement to mitigate beam systematics to prevent pollution of the CMB B-mode signal. In the first instance, a waveguide-coupled mesh lens is characterised. The radiation patterns of the waveguide-coupled mesh lens have -3 dB beam widths between 26 and 19 degrees, beam ellipticity <10%, and cross-polarisation.

Made available in DSpace on 2014-07-29T15:07:55Z (GMT). No. of bitstreams: 1 Dissertacao_Marlon.pdf: 1426156 bytes, checksum: 17813879cecb040cf30a2594c81b2185 (MD5) Previous issue date: 2009-11-16 / The monitoring and well care during the pregnancy is related to health born products. Considering that in canine reproduction the mate day is not a confident mark for fecundation because the sperm can be available during the estrus and the bitch can ovulate for seven to ten days and this can substimate the parturition day and the fetal growth. The knowledge of canine physiology and embryology during pregnancy and the pos partum associated of the correct application of diagnostic techniques help veterinarian to request for the best way to diagnose and chase the pregnancy. Physics examination, laboratory survey and imaging diagnostic are the principal tools for diagnose and prognoses of pregnancy. The image diagnostic is the most excellent technique to evaluate canine pregnancy. Radiographs and ultrasounds are accessible and can provide vital informations of the mother health and fetal development. This study s aim is to evaluate the morphological development of the bitch and fetus during pregnancy using high frequency transducer (12 MHz) and also compare the ability of the frequencies 7.5 MHz, 10 MHz and 12 MHz in measurements of fetal and extra fetal structures. To achieve this objectives it was scanned 25 bitch, two French bulldogs, one English bulldog, one American cocker spaniel, one lhasa-apso, two German sptiz, one Maltese, one pug, one schnauzer, two sheltland shepherd, ten shi-tzu and two Yorkshire terriers, weighting between three and 19 kilograms and age among two to six years from a commercial kennel, the animals were scanned by a unique examinator every seven days, the date day was used for mark the beginning of reproduction time, and the most near day of the date was the Zero week of scanning. The animals was follows by serial scanning and the events of the mother and the puppies were registered. The purpose of this study was to chase the pregnancy using high frequency transducer of 12MHz to determinate the period of appearance of fetal and extra fetal structures, which provides data s for parturition time and fetal maturity. The high frequency shows to be efficient for early diagnose of pregnancy, since was possible to identified the ovary and uterus with 2,7±2,1 days, gestational sac in 9,7±2,2 days of gestation, the embryos and heart beating were noticed with 16,7±2,2 days, the members arrows and bipolar shape appears in 23,7±2,2 days of pregnancy, fetal movement and de identification of the stomach were possible with 30,7±2,2 days, the bladder, skeleton, lungs and liver were visualized with 37,7±2,2 days, the kidney appears with 44,7±2,2 and pos partum uterus was identified with 65,7± 2,3days .Additionally contributing for seeking the fetal and extra fetal structures that provides security for estimation of parturiation date. Also was to propose a protocol of scanning to follow the preganancy period and pursue gestational diagnoses, fetal development and disorder during pregnancy comparing the ability of transducer of 7.5 MHz, 10 MHz and 12 MHz in the measurements and acoustic resolution. The gestation time was better avaluated in the second, fourth and seventh week, which shows the best protocol for track the pregnancy in the canine, additionally the high frequency demonstrate to improve the resolution and accuracy of measurements of fetal and extra fetal paramanters, but it not shows to be different from low frequency. / O acompanhamento da gestação e os cuidados pré-natais estão intimamente relacionados com o nascimento de filhotes sadios. Na espécie canina a data em que ocorre a fecundação é muito imprecisa, tendo em vista que as fêmeas podem ovular durante sete a dez dias e o espermatozóide pode permanecer viável e armazenado por todo o estro, com isso a cópula não representa o melhor indicador do dia da fecundação. O conhecimento detalhado dos eventos que ocorrem durante a fecundação, desenvolvimento e maturação fetal, bem como aqueles que permitem que o clínico veterinário possa indicar o meio de diagnóstico mais adequado, seguro e preciso sobre a evolução da gestação. O exame clínico, os exames laboratoriais e de imagem constituem-se em métodos auxiliares fundamentais para o diagnóstico e prognóstico da prenhez. Os meios de diagnóstico por imagem são excelências para avaliação da gestação na espécie canina, principalmente os exames radiográficos e ultrassonográficos, pois são acessíveis e fornecem informações importantes sobre a fêmea e sobre o desenvolvimento fetal. Com o objetivo de acompanhar, por meio de ultrassonografia, a gestação em cadelas de pequeno porte, utilizando transdutor de 12MHz este estudo teve como propósito determinar o período de surgimento das estruturas fetais e extra-fetais visando fornecer dados que contribuam para a estimativa da idade gestacional. O experimento foi realizado em um canil comercial, em 25 cadelas; dois bullldogs franceses, um bulldog inglês, um cocker spaniel americano, um lhasa apso, dois lulus da pomerânia, um maltês, um pug, um poodle, um schnauzer, dois pastores de sheltland, dez shi-tzu e dois yorkshire terrier, com peso corporal variando entre três e 19 quilogramas, e idade entre dois a seis anos. Todas as fêmeas eram pluríparas e a fecundação foi alcançada por meio de monta natural ou inseminação artificial A cada sete dias um único examinador procedeu os ultrassonogramas, sendo considerada como semana zero a semana do cruzamento natural ou inseminação até a décima semana . Os exames foram realizados nas freqüências 7,5 MHz, 10 MHz e 12 MHz para avaliar acurácia das medidas e a resolução acústica das imagens. A utilização da freqüência de 12 MHz permitiu a visibilização dos ovários e do útero pré- gestacional com 2,7±2,1 dias, vesículas gestacionais aos 9,7±2,2 dias, embrião e batimento cardíaco aos 16,7±2,2 dias, forma bipolar e o aparecimento da placenta e dos brotos dos membros aos 23,7±2,2 dias, movimento fetal e a visibilização do estomago dos fetos foi possível aos 30,7±2,2 dias, a bexiga urinaria, o esqueleto, os pulmões e o fígado foram visibilizados aos 37,7±2,2 dias, o rim aos 44,8±2,2 dias e o útero pós gestacional aos 65,7±2,3 dias, contribuindo para o diagnóstico precoce da prenhez, adicionalmente demonstrou ser eficaz na identificação das estruturas fetais e extra-fetais permitindo a estimativa do dia do parto. Durante as dez semanas de exames foram diagnosticadas duas piometras (entre a segunda e a sétima semanas), três cadelas não foram fecundadas (entre a segunda e quarta semanas) e duas cadelas onde constatou-se absorção de fetos (entre a terceira e quarta semanas) os resultados obtidos neste estudo permitem concluir que: o diagnóstico gestacional não deve ser feito em apenas um momento, sendo necessário uma seqüência de exames de acompanhamento gestacional; a segunda, quarta e sétima semanas são os melhores momentos para o pré-natal na espécie canina pois permitem avaliar os eventos de desenvolvimento e maturação fetal durante a gestação. O aumento da freqüência, quando comparada a frequências menores, imprime precocidade no diagnóstico e melhora a resolução da imagem, mas não o suficiente para promover diferenças no estabelecimento do diagnóstico da gestaçao e na acúracia das medidas de parâmetros extra-fetais e fetais.

Os desafios atuais no desenvolvimento de biossensores abrangem diversos aspectos, tais como a necessidade de se aperfeiçoar a interface de contato entre o substrato e o material biológico, a eficiência de transdução do sinal químico em um sinal mensurável, o tempo de resposta, a compatibilidade dos biossensores com matrizes biológicas e a integração de diferentes elementos de reconhecimento biológico em um único dispositivo, visando a detecção de distintos analitos. Nesse contexto, o desenvolvimento da nanociência tem criado recursos bastante atraentes para otimizar os aspectos descritos acima. O presente trabalho apresenta, portanto, estudos realizados para a construção de mediadores nanoestruturados que possam operar de maneira mais eficiente que os correspondentes materiais maciços (sistemas não-nanoestruturados). Em uma das abordagens utilizadas, um mediador híbrido de hexacianoferrato de cobre/polipirrol (CuHCNFe/Ppy) teve suas propriedades eletroquímicas aliadas às propriedades morfológicas e eletrônicas de um feltro revestido com nanotubos de carbono do tipo \"cup-stacked\" (feltro/NTCCS) para o desenvolvimento de um sensor de H2O2. O feltro/NTCCS é uma malha hidrofílica condutora que permite uma dispersão bastante uniforme do mediador híbrido. Essa característica, aliada ao aumento da área eletroativa e à interação eletrônica existente entre o CuHCNFe/PPy e os nanotubos de carbono criaram uma plataforma favorável para a construção de um biossensor de glicose. Em uma segunda estratégia, esferas de poliestireno com diâmetros de 300, 460, 600 e 800 nm foram utilizadas como molde para a formação de filmes de CuHCNFe/PPy macroporosos. Os distintos mediadores foram aplicados na detecção de H2O2 com o intuito de se correlacionar a importância do tamanho do poro com o desempenho analítico obtido. Diferentemente do esperado, os mediadores maciços e porosos apresentaram desempenhos analíticos bastante similares, o que levou a uma consideração das propriedades termodinâmicas de superfícies curvas, da molhabilidade de materiais porosos e da influência da cinética eletroquímica na utilização de sistemas porosos. Tais plataformas também foram aplicadas com sucesso na construção de biossensores de glicose e de colina. Por fim, foi possível sintetizar mediadores nanoestruturados através da imobilização de camadas de azul da Prússia e de CuHCNFe dentro das cavidades de filmes de TiO2 mesoporosos (13, 20 e 40 nm de diâmetro). Os resultados obtidos demonstraram a possibilidade de se modular o desempenho dos sensores de H2O2 em função do diâmetro dos poros e da quantidade de mediador imobilizado. A união dos resultados analíticos obtidos com os dados de microscopia eletrônica de varredura possibilitou observar a importância do efeito de confinamento no desempenho dos mediadores. Além disso, dados espectroscópicos na região do visível foram fundamentais para relacionar a presença de defeitos estruturais com a reatividade do material. No fim, tais plataformas foram utilizadas para a formulação de biossensores de colina. / Nowadays, the challenges in the development of biosensors cover various aspects such as the need to improve the interface between the substrate and the biological material, the efficiency of the chemical signal transduction in a measurable one, the response time, the compatibility with biological matrices and the integration of different biological recognition elements in a single device, in order to perform detections of different analytes. In this context, the development of nanoscience has created very attractive features to optimize the aspects described above. Consequently, the present work studies the build up of nanostructured transducers that can operate more efficiently than the corresponding bulk materials (systems non-nanostructured). In one of the approaches used, a hybrid transducer consisting of copper hexacyanoferrate/polypyrrole (CuHCNFe/Ppy) had its electrochemical properties combined with the morphological and electronic properties of a felt decorated with cup-stacked type carbon nanotubes (felt/CSCNT) for development of a H2O2 sensor. Felt/CSCNT is a hydrophilic conductive mesh that allows a uniform dispersion of the hybrid transducer. This feature, coupled with the improvement of electroactive surface and with the electronic interaction among the CuHCNFe/Ppy and carbon nanotubes have created a favorable platform for the construction of a glucose biosensor. In a second strategy, polystyrene spheres with diameters of 300, 460, 600 and 800 nm were used as templates for the formation of macroporous CuHCNFe/Ppy films. The transducers were used to detect H2O2 in order to correlate the importance of pore size with the obtained analytical performance. Unlike expected, porous and bulk transducers presented very similar analytical performances, which led to a consideration of the thermodynamic properties of curved surfaces, the wettability of porous materials and the influence of electrochemical kinetics during the use of porous systems. Such platforms have also been successfully applied in the preparation of glucose and choline biosensors. Finally, it was possible to synthesize nanostructured transducers through the immobilization of Prussian blue layers and CuHCNFe inside the cavities of mesoporous TiO2 films (pore diameters of 13, 20 and 40 nm). The obtained results demonstrated the possibility of modulating the performance of H2O2 sensors according to the pore diameter and the amount of immobilized transducer. The union of the obtained analytical results with scanning electron microscopy data showed the importance of confinement effect on the transducers performances. In addition, spectroscopic data in the visible region were essential to correlate the presence of structural defects with the material reactivity. In the end, these platforms were used for the formulation of choline biosensors.