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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Integration of functional components into microfluidic chemical systems: bioimmobilization and electrochemiluminescent detection on-chip

Zhan, Wei 29 August 2005 (has links)
We have investigated and implemented several general strategies in the development of microfluidics-based chemical/biochemical sensing systems. The research in this dissertation covers the immobilization of biological reagents inside microfluidic channels using polystyrene (PS) microbeads and photopolymerizable hydrogel, electrochemical sensing via electrochemiluminescence (ECL) reporting with bipolar and two-electrode configurations, and integration of these general functions to realize multiplexing and networking on-chip. Photopolymerizable hydrogel based on Poly(ethylene glycol) (PEG) and streptavidin-coated polystyrene (PS) microbeads were employed as building blocks as well as functional components in microfluidic system. PEG hydrogels can be used to define local microenvironments at different locations in the same microchannel, which enables the introduction of multiple sensing events on the same device. Monitoring of DNA hybridization and enzyme/substrate interaction were realized thereafter by using either fluorescence or electrochemistry as the detection method. Electrogenerated chemiluminescence based on Ru(bpy)32+ (bpy = 2,2??-bipyridine) and tripropylamine (TPA) was used to photonically report various redox events in microfluidic systems. By using microfluidic electrochemical cells based on either two-electrode or bipolar electrode (one-electrode), electroactive species that undergo reduction can be electrically linked to this anodic ECL process and thus be reported by the latter. This ECL sensing scheme essentially broadens the spectrum of redox compounds that can be detected by ECL since the analytes are not required to directly participate into the light-generating processes. Microfluidics offers some unique technical advantages of performing electrochemistry over conventional methods. In particular, laminar flow allows multiple analyte streams to be brought together in parallel with little mixing. Moreover, electrochemical signals can be generally utilized as a convenient means to link individual microchannels together hence to realize microfluidic networking and cross-communication. Electrochemical microfluidic devices can be used to mimic general functions of microelectronic devices such as diodes, transistors, and logic gates. These novel functions rendered by electrochemistry are believed to bring us closer to the final goals of micro total analysis systems and lab-on-a-chip.
2

Integration of functional components into microfluidic chemical systems: bioimmobilization and electrochemiluminescent detection on-chip

Zhan, Wei 29 August 2005 (has links)
We have investigated and implemented several general strategies in the development of microfluidics-based chemical/biochemical sensing systems. The research in this dissertation covers the immobilization of biological reagents inside microfluidic channels using polystyrene (PS) microbeads and photopolymerizable hydrogel, electrochemical sensing via electrochemiluminescence (ECL) reporting with bipolar and two-electrode configurations, and integration of these general functions to realize multiplexing and networking on-chip. Photopolymerizable hydrogel based on Poly(ethylene glycol) (PEG) and streptavidin-coated polystyrene (PS) microbeads were employed as building blocks as well as functional components in microfluidic system. PEG hydrogels can be used to define local microenvironments at different locations in the same microchannel, which enables the introduction of multiple sensing events on the same device. Monitoring of DNA hybridization and enzyme/substrate interaction were realized thereafter by using either fluorescence or electrochemistry as the detection method. Electrogenerated chemiluminescence based on Ru(bpy)32+ (bpy = 2,2??-bipyridine) and tripropylamine (TPA) was used to photonically report various redox events in microfluidic systems. By using microfluidic electrochemical cells based on either two-electrode or bipolar electrode (one-electrode), electroactive species that undergo reduction can be electrically linked to this anodic ECL process and thus be reported by the latter. This ECL sensing scheme essentially broadens the spectrum of redox compounds that can be detected by ECL since the analytes are not required to directly participate into the light-generating processes. Microfluidics offers some unique technical advantages of performing electrochemistry over conventional methods. In particular, laminar flow allows multiple analyte streams to be brought together in parallel with little mixing. Moreover, electrochemical signals can be generally utilized as a convenient means to link individual microchannels together hence to realize microfluidic networking and cross-communication. Electrochemical microfluidic devices can be used to mimic general functions of microelectronic devices such as diodes, transistors, and logic gates. These novel functions rendered by electrochemistry are believed to bring us closer to the final goals of micro total analysis systems and lab-on-a-chip.
3

Miniaturisation et intégration optofluidique : vers une nouvelle source électrochimiluminescente autonome / Optofluidic miniaturisation and integration : toward a new electrochemiluminescence light source

Méance, Sébastien 16 September 2011 (has links)
Depuis que l’optofluidique a été introduite au début des années 2000, beaucoup de dispositifs combinant à la fois l’optique et la microfluidique ont été développés. Ces travaux ont proposé de nombreuses voies originales pour l’analyse biologique et le diagnostique médical. Parmi ceux-ci, citons par exemple, les guides d’ondes liquide-liquide (également appelés guides d’ondes L2), les lentilles liquides adaptatives, les lasers multicolores à microgouttes, ou encore les microscopes optofluidiques sans lentilles.Ces systèmes offrent de nombreux avantages liés à la microfluidique comme leurs flexibilités et leurs accordabilités. Néanmoins, la plupart de ces systèmes reposent sur l’utilisation d’une source de pompage optique externe devant être couplée aux puces microfluidiques avec le plus grand soin.Le but de ces travaux de thèse est d’augmenter l’autonomie et la portabilité des systèmes optofluidiques en intégrant directement la source lumineuse sur les puces. Nous proposons donc ici d’exploiter la voie électrochimiluminescente comme méthode de pompage électrique. L’annihilation du luminophore 9,10-Diphenylanthracene permet ainsi d’obtenir une faible longueur d’onde d’émission dans le domaine du visible.Ainsi nous montrons dans ces travaux la mise en œuvre d’une nouvelle technologie de fabrication pour réaliser un circuit optofluidique d’une source lumineuse intégrée. La fabrication de cette puce a permis d’obtenir des résultats d’électrochimiluminescence sur puce montrant ainsi la compatibilité de cette approche. Les expériences effectuées pendant ces travaux ouvrent ainsi la voie au pompage électrique sur dispositifs optofluidiques. / Since optofluidics was introduced in the early 2000s, a lot of devices combining microfluidic and optic have been developed such as L2 waveguides, adaptive liquid lenses, microdroplet multicolour dye laser, or lensless optofluidics microscopes.These systems offer many advantages allowed by microfluidic like flexibility and accordability. However most of them generally need an external optical source carefully coupled to the microfluidic device.The purpose of this PhD thesis is to improve autonomy and portability of microfluidics systems integrating light source on the chip. Hence, we suggest here to use the electrochemiluminescence way to reach electrical pumping. 9,10-Diphenylanthracene annihilation allowed us to obtain a low wavelength in the visible domain.Therefore, we show here the implementation of a new fabrication technology to make an integrated on chip optical source. The chip fabrication allowed us to obtain on chip electrochemiluminescence results showing the compatibility of this approach. The experiments realised during these works open the way to electrical pumping way on optofluidic chips.
4

Study of comparative bioavailability among two formulations containing sodic levothyroxine in healthy volunteers. / Estudo de bio disponibilidade comparativa entre duas formulaÃÃes contendo levotiroxina sÃdica em voluntÃrios sÃdios.

PacÃfica Pinheiro Cavalcanti 21 August 2005 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / O tratamento de escolha para o hipotireoidismo à a levotiroxina sÃdica. Estudos de biodisponibilidade com medicamentos com caracterÃsticas hormonais tÃm grande importÃncia na garantia do controle da qualidade dos fÃrmacos disponÃveis à populaÃÃo. Logo, o objetivo deste estudo foi: Determinar a biodisponibilidade de duas formulaÃÃes de 150 &#956;g de levotiroxina sÃdica em indivÃduos sadios; apÃs Ãnica administraÃÃo de 600 &#956;g, por via oral e comparÃ-las .A pesquisa consistiu de um estudo aberto, randomizado, cruzado, com dois tratamentos, dois perÃodos (duas seqÃÃncias), nos quais os 24 voluntÃrios, saudÃveis e de ambos os sexos, receberam, em cada perÃodo distinto, a formulaÃÃo teste do Achà LaboratÃrios FarmacÃuticos S.A. ou a formulaÃÃo referÃncia da Sanofi-Synthelabo Ltda. (Puran ÂT4). Foi utilizado o imunoensaio de eletroquimioluminescÃncia para dosar as concentraÃÃes dos hormÃnios T3 (liotironina) e T4 (levotiroxina) nas amostras de soro dos voluntÃrios e posterior determinaÃÃo dos parÃmetros farmacocinÃticos. Os resultados da anÃlise de variÃncia (ANOVA) da Levotiroxina demonstraram um significante efeito de perÃodo com diminuiÃÃo dos nÃveis sÃricos do T4, no segundo internamento, independente da aleatorizaÃÃo (p<0,05). As razÃes das mÃdias geomÃtricas do Cmax e ASC0-48h das formulaÃÃes teste e referÃncia foram 92,97% e 97,87%, respectivamente. Os intervalos de confianÃa de 90% foram de 88,70â 97,44% e 93,10 - 102,88%, respectivamente. As formulaÃÃes de comprimidos de 150microg de levotiroxina sÃdica estudadas apresentaram biodisponibilidades semelhantes, quando administradas em dose Ãnica de 600microg, por via oral a voluntÃrios sadios; sendo entÃo consideradas bioequivalentes.
5

Electrochemiluminescence and organic electronics of derivatised poly(aniline sulphonic acid) light-emitting diodes

Molapo, Kerileng Mildred January 2011 (has links)
>Magister Scientiae - MSc / Applications of electrochemiluminescent conjugated polymers offer promising solutions in addressing the problem of light emitting devices. However, the challenging problems that hamper their application in light emitting devices are loss of signal due to diffusion of the electrochemiluminescence (ECL) reagent out of the detection zone, limited ability to repeatedly cycle an individual luminophore and high reagent consumption. In this work, the main objective was to produce conducting polymers with enhanced electrochemiluminescence by tuning the properties of the polymer itself. The electrochemical and photophysical properties of films of polyaniline (PANI) and poly(8-anilino-1- naphthalene sulfonic acids) (PANSA) synthesized through electro- and chemical polymerization methods were also investigated. The electrosynthesis of PANSA undoped and doped with anthracene sulfonic acid (ASA), 1,2-naphthaquinone-4-sulfonic acid (NSA) and carbon nanotubes (CNT) in acid medium was investigated and the cyclic voltammograms (CV) showed the growth of the polymer during polymerization. The CV multiscan characterization displayed that the growth of the polymer was dependent of the scan rate and the three redox couples were observed as indicative of the three redox states of typical polyaniline and its derivatives. The results also showed that the peak currents were diffusion controlled and the electron charge transport coefficient (De) of the electrosynthesized polymers was found to range between 10⁻⁸ and 10⁻⁹ cm² s⁻¹ for PANSA, PANSA-ASA, PANSA-NSA and PANSA-CNT. The De value indicates that the movement of electrons along the polymer chain was averagely fast. The transmission electron microscopy (TEM) was used to investigate the electronic morphology of the polymers and the TEM images showed an intertwinement of tubings which aggregate into a ring with a mixture of tubings and plastic sheets. The chemical synthesis of PANI, PANSA and PANI-NSA was carried out by using monomers analine, 8-anilino-1-naphthalene sulfonic acid, and aniline with 1,2- naphthaquinone-4-sulfonic acid, respectively, using oxidants. All chemically synthesized polymers exhibited quinoid and benzoid bands typically see in polyaniline FTIR and Raman spectra confirmed the successfully formation of polymers. The CV characterization of these polymers showed distinctive redox peaks. This proved that the polymers were electroactive, conductive and exhibited reversible electrochemistry. The De of the electrosynthesized polymers was found to be ~10⁻⁵ cm² s⁻¹ for chemically synthesized polymers. The electric conductivity measurement showed to increase from 10⁻⁴ to 10⁻² when aniline was polymerized with NSA dopant, this might be related to the process of electron transfer from dopant to polymer. Scanning electron microscopy for external morphology showed that the polymers were made of different nano- rods polymeric structures. Photophysical properties of electro- and chemically synthesized PANSA and PANI were investigated through UV-vis absorption, fluorescence behaviour, and lifetime. The UV-vis absorption spectra of these polymers showed that they exhibited absorption bands corresponding to the polyemeraldine redox state of typical polyaniline. The effect of dopants resulted in the increase in solubility of the polymers with a small shift of absorption bands due to incorporation of dopants in to the backbone of the polymer. The fluorescence emission spectra of the electrochemically synthesized PANSA with and without dopants were observed to be similar and mirror image of the excitation spectra and corresponding to the electronic band of the benzoid ring in the polyemeraldine form confirming that the fluorescing molecule in these polymers were the benzoid rings. However, the emission spectra of the chemically synthesized PANSA and PANI were different to excitation spectra due to loss of symmetry upon excitation. The effects of chemically synthesized PANI, PANSA and PANI-NSA addition on the photophysical properties of [Ru(bpy)₂(picCOOH)]²⁺.(ClO₄⁻)₂) were investigated in order to understand the interaction of polymer and [Ru(bpy)₂(picCOOH)]²⁺.(ClO₄⁻)₂. The analysis revealed that the presence of polyaniline and its derivatives enhanced the [Ru(bpy)₂(picCOOH)]²⁺.(ClO₄⁻)2 absorption band, photoluminescence and fluorescence lifetime. The enhancement observed from interaction of [Ru(bpy)₂(picCOOH)]²⁺.(ClO₄⁻)₂ with polyaniline and its derivatives might be due to the excited state electron transfer from the PANI and PANSA excited state to the [Ru(bpy)₂(picCOOH)]²⁺.(ClO₄⁻)₂. It was further demonstrated in this work that it is possible to form polyaniline and PANSA doped with [Ru(bpy)₂(picCOOH)]²⁺.(ClO₄⁻)₂ films on ITO electrode using potentiostatic growth method to favour ECL production. The results showed that all films generated ECL in the presence of Tripropylamine (TPA) as a co-reactant and their emission properties depend on time used to prepare the film. The enhancement of ECL signal was due to a positive electron transfer from the conducting polymer (PANI and PANSA) to [Ru(bpy)₂(picCOOH)]²⁺.(ClO₄⁻)₂ complex. The results highlighted the potential of these polymeric luminophores usage in the manufacturing of the ECL devices.
6

Electrochemiluminescence at Bare and DNA-Coated Graphite Electrodes in 3D-Printed Fluidic Devices

Bishop, Gregory W., Satterwhite-Warden, Jennifer E., Bist, Itti, Chen, Eric, Rusling, James F. 26 February 2016 (has links)
Clear plastic fluidic devices with ports for incorporating electrodes to enable electrochemiluminescence (ECL) measurements were prepared using a low-cost, desktop three-dimensional (3D) printer based on stereolithography. Electrodes consisted of 0.5 mm pencil graphite rods and 0.5 mm silver wires inserted into commercially available 1/4 in.-28 threaded fittings. A bioimaging system equipped with a CCD camera was used to measure ECL generated at electrodes and small arrays using 0.2 M phosphate buffer solutions containing tris(2,2′-bipyridyl)dichlororuthenium(II) hexahydrate ([Ru(bpy)3]2+) with 100 mM tri-n-propylamine (TPA) as the coreactant. ECL signals produced at pencil graphite working electrodes were linear with respect to [Ru(bpy)3]2+ concentration for 9-900 μM [Ru(bpy)3]2+. The detection limit was found to be 7 μM using the CCD camera with exposure time set at 10 s. Electrode-to-electrode ECL signals varied by ±7.5%. Device performance was further evaluated using pencil graphite electrodes coated with multilayer poly(diallyldimethylammonium chloride) (PDDA)/DNA films. In these experiments, ECL resulted from the reaction of [Ru(bpy)3]3+ with guanines of DNA. ECL produced at these thin-film electrodes was linear with respect to [Ru(bpy)3]2+ concentration from 180 to 800 μM. These studies provide the first demonstration of ECL measurements obtained using a 3D-printed closed-channel fluidic device platform. The affordable, high-resolution 3D printer used in these studies enables easy, fast, and adaptable prototyping of fluidic devices capable of incorporating electrodes for measuring ECL.
7

Development of a Novel Electrochemiluminescent Reaction Involving Cadmium

Whitchurch, Christian J. 05 April 2002 (has links)
No description available.
8

Investigation of Charge Transfer in Metal-Organic Frameworks for Electrochemical Applications

Cai, Meng 20 March 2020 (has links)
High-performance functional electrode materials are critical for the development of electrochemical energy conversion and storage technologies. Among various advanced materials, three-dimensional (3D) porous structures have attracted extensive interest due to their high surface area and capability for efficient mass transport. Metal-organic frameworks (MOFs) are a novel class of porous coordination polymers constructed with organic linkers connected by inorganic nodes. Their extraordinarily high surface area, permanent pores/channels, good thermal and chemical stabilities have made MOFs one of the most promising materials for various electrochemical applications, including electrocatalysis, supercapacitors, Lithium-ion batteries, chemical sensors, etc. The present dissertation focuses on the investigation of charge transfer mechanism in MOF films so as to establish design rules for future MOF design, and the exploration of MOF-based materials for electrochemical and photoelectrochemical applications. To promote the use of MOF-based materials in electrochemical applications, efficient charge transfer is a necessity. In redox-active MOFs, charge transfer can happen through redox hopping, i.e. site-to-site electron hopping coupled to diffusion of counter ions to balance electroneutrality. While the apparent diffusion coefficient (Dapp) has been employed to describe the overall charge transfer efficiency, independent elucidation of electron and ion diffusion is crucial for providing insights into the mechanism of charge transfer in MOFs. In Chapter 2, we investigated the MOF pore size effect on electron and ion diffusion. Three redox-active ferrocene-doped MOF (Fc-MOF) films with different pore sizes immobilized on conductive substrates were prepared, and electron and ion diffusion coefficients and rate constants were quantified by applying a theoretical model to chronoamperometric responses. Increasing MOF pore size led to an increase in ion diffusion rate constant and a decrease in electron diffusion rate constant. The overall charge transfer rate constant increased when MOF pore size increased, implying the ability of promoting efficient charge transfer through control of MOF pore size. As charge transfer via redox hopping proved to be feasible, Chapter 3 focused on the application of a ruthenium(II)-polypyridyl doped MOF film immobilized on a conductive substrate, UiO-67-Ru@FTO, for solid-state electrochemiluminescence (ECL). In the presence of tripropylamine as a coreactant, UiO-67-Ru@FTO exhibited higher ECL intensity and better reproducibility compared to corresponding solution-based ECL system. Subsequently, UiO-67-Ru@FTO was successfully used for dopamine detection, highlighting the great potential of using MOF-based materials as solid-state ECL detector for practical applications. Covalent-organic frameworks (COFs) are a recently emerging family of crystalline organic polymers constructed with organic building blocks linked by covalent bonds. In addition to advantages including high surface area and high porosity that are similar to MOFs, COFs possess low density due to the constitution of light-weighted elements and excellent stability owing to the robust covalent bonds. Therefore, it is of our interest to investigate the properties and potential applications of COFs. Two-dimensional (2D) COFs are composed of conjugated organic layers stacked via - interactions. Chapter 4 focused on understanding the effects of intraplanar -conjugation and interplanar -stacking on the photophysical properties of a 2D COF, TpBpy. Compared to the two building blocks, TpBpy exhibited a red-shifted emission, due to the - stacking. Density functional theory (DFT) calculations were performed on energies of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). It was found that the extended structure of the framework resulted in a decrease in the HOMO-LUMO gap. The experimental and computational studies reveal the important influence of intraplanar and interplanar interactions on photophysical properties in 2D COFs. In Chapter 5, we modified the COF TpBpy with nickel(II) and investigated its application as an electrocatalyst for 5-hydroxymethylfufural (HMF) oxidation. Unlike TpBpy characterized in Chapter 4, TpBpy thin films were prepared by an interfacial crystallization strategy. The films were transferred to conductive substrates and then post-synthetically modified by nickel acetate. Similar to redox-active MOFs, the resulting TpBpy-Ni COF film exhibited redox conductivity. TpBpy-Ni showed good catalytic activity for HMF oxidation under basic conditions. This study suggests the great potential of functionalized COFs for electrochemical applications. / Doctor of Philosophy / The increasing demand for clean and efficient energy has triggered a great deal of research interest in developing novel energy conversion and storage technologies. In particular, electrochemical (EC) systems including supercapacitors, Lithium-ion batteries, artificial photosynthetic system, fuel cells, etc. have drawn significant attention. The key component in high-performance EC energy conversion and storage devices is the functional electrode materials. Three-dimensional (3D) porous nanostructures have been widely applied as advanced electrode materials due to their high surface area that enables more liquid/solid interfacial interactions, and pores/channels that allows efficient mass diffusion and transport. Metal-organic frameworks (MOFs), made of organic ligands bridged by inorganic nodes, are a novel kind of porous materials with extraordinarily high surface area and permanent porosity. As a result, there is great potential in developing MOF-based electrode materials for EC applications. As the name itself suggests, EC systems rely on electrochemical reactions that involve transfer of charges (i.e. electrons and ions). Therefore, efficient charge transfer is vital for achieving high performance. While MOFs used for gas separation and storage have been reported, their electrochemical applications are still in early stages. The fundamental understanding of charge transfer in MOFs is in its infancy. As a result, there is an urgent demand for understanding the nature of charge transfer in MOFs. In this dissertation, we investigated the mechanism of charge transfer by independent quantification of electron and ion transfer rate constants. With a better understanding in hand, we also explored two electrochemical applications in MOFs, electrocatalysis and electrogenerated chemiluminescence.
9

Estudo de sensores baseados em luminescência eletroquímica (ECL) sem marcadores. / Study of electrochemiluminescence (ECL) based sensors without markers.

Pereira, Rodrigo Solano 12 December 2016 (has links)
Esta pesquisa apresenta o desenvolvimento de um sensor para fenotiazina baseados em luminescência eletroquímica (ECL) com Ru(bpy)3 como elemento ativo. Para desenvolver este sensor, foram utilizados três materiais como eletrodo de trabalho, sendo estes materiais carbono vitreo, ouro e oxido de índio-estanho (ITO). O eletrodo de trabalho é modificado com a deposição de um filme fino de TiO2/nafion. O desempenho de cada material é comparado com os demais e com dados já apresentados na literatura. A novidade apresentada por esta pesquisa é a utilização de ouro e ITO como eletrodos de trabalho para o sistema de ECL Ru(bpy)/fenotiazina. Também, esta pesquisa apresenta um estudo sobre a influência da espessura do filme sobre a intensidade do sinal de ECL. Os estudos apresentados nesta dissertação se referem à otimização do filme de TiO2/nafion e do eletrodo de trabalho utilizado, visando produzir o sensor mais sensível à presença de fenotiazina em uma solução fisiológica. Sensores que utilizam o fenômeno da ECL para detecção de analitos são utilizados com frequência por apresentarem grande sensibilidade e seletividade. Sua principal aplicação se encontra em sistemas onde o analito é uma macromolécula, uma amina, caso comum para soluções fisiológicas. Fenotiazina é uma substância interessante como alvo porque seus derivados são largamente utilizados em drogas para o tratamento de doenças psiquiátricas, como depressão e esquizofrenia. Então, se faz necessário monitorar de maneira segura a ingestão e absorção desses medicamentos pelos pacientes. / This research presents the development of a electrochemioluminescence (ECL) based sensor aimed to detect phenothiazine in physiologic solutions. To develop this sensor, three materials were used, being glass carbon, gold and indium-tin oxide (ITO) for the working electrode of the sensor. The working electrode was modified by the deposition of a composite thin film of TiO2/nafion in its surface. Each material then was compared in terms of the ECL signal intensity between themselves and data from previous researches. The novelty presented in this work is the use of gold and ITO as base materials for the working electrode of the sensor. Also, as a novelty, this research presents a study of the influence of the film thickness over the ECL signal intensity. This thesis presents studies concerning the optimization of the TiO2/nafion film and the influence of the working electrode material, aiming to produce the best possible sensor for phenothiazine in physiological solutions. ECL based sensor are often used today due to their great selectivity and sensibility. They are mainly used for detecting macromolecules, such as DNA and proteins in physiologic solutions. Phenothiazine is an interesting substance because its derivatives are commonly used on pharmaceutical drugs used to treat phycological diseases, such as depression and schizophrenia.
10

Estudo de sensores baseados em luminescência eletroquímica (ECL) sem marcadores. / Study of electrochemiluminescence (ECL) based sensors without markers.

Rodrigo Solano Pereira 12 December 2016 (has links)
Esta pesquisa apresenta o desenvolvimento de um sensor para fenotiazina baseados em luminescência eletroquímica (ECL) com Ru(bpy)3 como elemento ativo. Para desenvolver este sensor, foram utilizados três materiais como eletrodo de trabalho, sendo estes materiais carbono vitreo, ouro e oxido de índio-estanho (ITO). O eletrodo de trabalho é modificado com a deposição de um filme fino de TiO2/nafion. O desempenho de cada material é comparado com os demais e com dados já apresentados na literatura. A novidade apresentada por esta pesquisa é a utilização de ouro e ITO como eletrodos de trabalho para o sistema de ECL Ru(bpy)/fenotiazina. Também, esta pesquisa apresenta um estudo sobre a influência da espessura do filme sobre a intensidade do sinal de ECL. Os estudos apresentados nesta dissertação se referem à otimização do filme de TiO2/nafion e do eletrodo de trabalho utilizado, visando produzir o sensor mais sensível à presença de fenotiazina em uma solução fisiológica. Sensores que utilizam o fenômeno da ECL para detecção de analitos são utilizados com frequência por apresentarem grande sensibilidade e seletividade. Sua principal aplicação se encontra em sistemas onde o analito é uma macromolécula, uma amina, caso comum para soluções fisiológicas. Fenotiazina é uma substância interessante como alvo porque seus derivados são largamente utilizados em drogas para o tratamento de doenças psiquiátricas, como depressão e esquizofrenia. Então, se faz necessário monitorar de maneira segura a ingestão e absorção desses medicamentos pelos pacientes. / This research presents the development of a electrochemioluminescence (ECL) based sensor aimed to detect phenothiazine in physiologic solutions. To develop this sensor, three materials were used, being glass carbon, gold and indium-tin oxide (ITO) for the working electrode of the sensor. The working electrode was modified by the deposition of a composite thin film of TiO2/nafion in its surface. Each material then was compared in terms of the ECL signal intensity between themselves and data from previous researches. The novelty presented in this work is the use of gold and ITO as base materials for the working electrode of the sensor. Also, as a novelty, this research presents a study of the influence of the film thickness over the ECL signal intensity. This thesis presents studies concerning the optimization of the TiO2/nafion film and the influence of the working electrode material, aiming to produce the best possible sensor for phenothiazine in physiological solutions. ECL based sensor are often used today due to their great selectivity and sensibility. They are mainly used for detecting macromolecules, such as DNA and proteins in physiologic solutions. Phenothiazine is an interesting substance because its derivatives are commonly used on pharmaceutical drugs used to treat phycological diseases, such as depression and schizophrenia.

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