Das dopaminerge und das serotonerge Transmissionssystem sind zwei wichtige Transmissionssysteme, die in eine Vielzahl von Krankheiten des ZNS involviert sind. Es ist gut bekannt, daß eine enge Interaktion zwischen beiden Systemen stattfindet. Krankheiten des ZNS, die sich auf umschriebene Veränderungen zurückführen lassen, haben durch die Interaktionen von Transmissionssystemem weitreichende Folgen auf verschiedene Bereiche des Gehirns. Neuere Therapien machen sich diese Interaktionen zunutze, um in das Krankheitsgeschehen einzugreifen. In der vorliegenden Arbeit wurde die Reaktion des dopaminergen Systems auf eine genetische Veränderung im serotonergen System untersucht. Die untersuchten transgenen Tiere besaßen ein Gensequenz, die für eine Antisense-m-RNA gegen die m-RNA der TPH kodierte. Die TPH katalysiert den geschwindigkeitsbestimmenden Schritt der Serotoninbiosynthese. Zur Charakterisierung des dopaminergen Systems wurden die Freisetzung und die hochaffine Wiederaufnahme durch den DAT als Parameter ausgewählt. Die Freisetzung aus Synaptosomenpräparationen war bei den transgenen Tieren signifikant gegenüber den nicht-transgenen Tieren erniedrigt. Bei der hochaffinen Wiederaufnahme ließen sich keine Unterschiede zwischen transgenen und nicht-transgenen Tieren feststellen. Die beobachtete Erniedrigung der Freisetzung bestätigt die Erkenntnisse einer Vielzahl von Studien, die einen stimulatorischen Einfluss von Serotonin auf das dopaminerge System beschreiben. / The dopaminergic and the serotonergic transmission systems are two important systems that are involved in a great number of central nervous system (CNS) diseases. It has long been known that a close interaction exists between them. Due to the interactions of transmission systems diseases of the CNS located on a identifiable spot have far-reaching consequences on other systems. Newer therapies take advantage of these interactions in order to interfere with the pathologic process. This study was performed to investigate how the dopaminergic system reacts to a alteration in the serotonergic system. The observed transgenic animals carried the gene for an antisense-construct against the m-RNA of tryptophahydroxylase (TPH). TPH catalyzes the rate limiting step in serotonin biosynthesis. In order to characterize the dopaminergic system 2 parameters were chosen: dopamine release and dopamine high affinity reuptake. The following results were obtained: Release of dopamine from synaptosomal preparations was decreased significantly in comparison to non-transgenic control animals. No difference concerning high affinity dopamine reuptake measured by continuous potential amperometry was noted. The findings concerning release of dopamine are in line with studies describing a facilitatory effect of serotonin on the dopaminergic system.

<p>The main hypothesis in this study is the development of a nanocomposite mediated amperometric biosensor for detection of hydrogen peroxide. The aim is to combine the electrochemical properties of both polyaniline and ferrocenium hexafluorophosphate into highly conductive nano composites capable of exhibiting electrochemistry in non acidic media / shuttling electrons between HRP and GCE for biosensor applications.</p>

The main objective of this work was to develop simple and sensitive electrochemical sensors for the detection of bisphenol A. To investigate the electrochemical behavior of BPA on a bare glassy carbon electrode. To apply the developed biosensor for the determination BPA by differential pulse voltammetry, electrochemical impedance spectrometry, square wave voltammetry and steady-state amperometry. To characterize the synthesized PDMA-PSS by cyclic voltammetry (CV), UV-Vis spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM).

<p>The main hypothesis in this study is the development of a nanocomposite mediated amperometric biosensor for detection of hydrogen peroxide. The aim is to combine the electrochemical properties of both polyaniline and ferrocenium hexafluorophosphate into highly conductive nano composites capable of exhibiting electrochemistry in non acidic media / shuttling electrons between HRP and GCE for biosensor applications.</p>

The main objective of this work was to develop simple and sensitive electrochemical sensors for the detection of bisphenol A. To investigate the electrochemical behavior of BPA on a bare glassy carbon electrode. To apply the developed biosensor for the determination BPA by differential pulse voltammetry, electrochemical impedance spectrometry, square wave voltammetry and steady-state amperometry. To characterize the synthesized PDMA-PSS by cyclic voltammetry (CV), UV-Vis spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM).

Magister Scientiae - MSc / The main objective of this work was to develop simple and sensitive electrochemical sensors for the detection of bisphenol A. To investigate the electrochemical behavior of BPA on a bare glassy carbon electrode. To apply the developed biosensor for the determination BPA by differential pulse voltammetry, electrochemical impedance spectrometry, square wave voltammetry and steady-state amperometry. To characterize the synthesized PDMA-PSS by cyclic voltammetry (CV), UV-Vis spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM). / South Africa

Data de aprova??o ausente. / Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-03-24T17:42:56Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) amanda_barbosa_lima.pdf: 1709527 bytes, checksum: 4fddb4fdbd889c4c7f3a82be7a0edabe (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-04-20T19:16:33Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) amanda_barbosa_lima.pdf: 1709527 bytes, checksum: 4fddb4fdbd889c4c7f3a82be7a0edabe (MD5) / Made available in DSpace on 2017-04-20T19:16:33Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) amanda_barbosa_lima.pdf: 1709527 bytes, checksum: 4fddb4fdbd889c4c7f3a82be7a0edabe (MD5) Previous issue date: 2016 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Verapamil (VP) e Oxcarbazepina (OX) s?o f?rmacos de baixo ?ndice terap?utico que necessitam de rigoroso controle de qualidade em formula??es farmac?uticas, bem como de an?lises em fluidos biol?gicos para estudos farmacol?gicos de elimina??o dessas drogas. Neste sentido, o desenvolvimento de m?todos simples, r?pidos e de baixo custo ? de extrema import?ncia para quantifica??o desses f?rmacos nessas amostras. Deste modo, o presente trabalho apresenta um m?todo eletroanal?tico em fluxo para determinar VP e OX tanto em formula??es farmac?uticas, quanto em amostras de urina. A t?cnica eletroqu?mica utilizada para quantifica??o foi a Amperometria de M?ltiplos Pulsos (MPA) acoplada a um sistema de an?lise por inje??o em fluxo (FIA), utilizando o diamante dopado com boro (BDD). Foram aplicados tr?s pulsos de potencial pela MPA para determina??o do VP em meio de ?cido sulf?rico 0,1 mol L-1, sendo +1,6 V para a oxida??o e, posteriormente, +0,2 V para redu??o do produto gerado do VP e +0,1 V para a limpeza do eletrodo de BDD. Para a determina??o de OX, tamb?m foram otimizados tr?s pulsos de potencial em meio de tamp?o acetato 0,1 mol L-1 (pH 4,0), sendo + 1,7 V para a oxida??o da OX e gera??o do produto que foi reduzido em -1,1 V e -1,3 V para a limpeza do eletrodo de BDD. Em ambos os casos, apenas o sinal obtido nos pulsos de potencial de redu??o foram utilizados para quantifica??o dos f?rmacos. As faixas lineares de trabalho obtidas para quantifica??o do VP e da OX foram de 0,8 a 40,0 ?mol L-1 (R= 0,9976) e 2,0 a 80,0 ?mol L-1 (R= 0,9989), respectivamente. Os limites de detec??o foram calculados em 0,16 ?mol L-1 para VP e 0,42 ?mol L-1 para OX. Uma boa repetibilidade foi obtida para 10 an?lises consecutivas desses f?rmacos, com desvio padr?o relativo de 2,2% para VP e 0,94 % para OX. Os estudos de adi??o e recupera??o do VP e OX em amostras farmac?uticas e urina apresentaram resultados pr?ximos a 100% e o doseamento do VP foi validado pela metodologia oficial. Altas frequ?ncias anal?ticas foram alcan?adas pelo sistema FIA com 45 e 65 determina??es por hora de VP e OX, respectivamente, usando al?as de amostragem inferiores a 200 ?L e vaz?es de 3,5 mLmin-1. An?lises desses f?rmacos em amostras de urina mostraram que ? poss?vel determin?-los mesmo na presen?a de altas concentra??es de ?cido asc?rbico e ?cido ?rico. Portanto, o m?todo proposto mostrou-se como alternativa simples e r?pida para quantifica??o desses f?rmacos em formula??es farmac?uticas e urina. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Qu?mica, Universidade Federal dos Vales do Jequitinhonha e Mucuri, [2016]. / Verapamil (VP) and Oxcarbazepine (OX) are drugs of narrow therapeutic index that require strict quality control in pharmaceutical formulations and analysis in biological fluids for pharmacological studies of elimination of these drugs. In this sense, the development of simple, fast and low-cost methods is very important to quantify these drugs in pharmaceutical samples. Therefore, this work presents a electroanalytical method in flow for determining VP and OX in pharmaceutical formulations and human urine samples. The electrochemical technique used for quantification was performed by multiple pulses amperometry (MPA) coupled to a flow injection analysis system (FIA), using boron-doped diamond (BDD) as working electrode. Were applied three potential pulses by MPA for the determination of VP in sulfuric acid 0.1 mol L-1: (1) +1.6 V for oxidation of VP, (2) +0.2 V for reduction of the generated product of VP in the fisrt potential pulse, (3) +0.1 V for cleaning of the BDD electrode surface. The determination of OX also was performed by MPA in three potential pulses in 0.1 mol L-1 acetate buffer (pH 4.0): (1) +1.7 V for oxidation of OX and generation of the product that it was reduced at (2) -1.1 V, and (3) -1.3 V for cleaning of the BDD electrode surface. In both cases, only the signal obtained in the reduction potential pulses were used for quantification of drugs. The linear ranges of work obtained for quantitation of VP and OX were 0.8 to 40.0 ?mol L-1 (R = 0.9976) and 2.0 to 80.0 ?mol L-1 (R = 0, 9989), respectively. The detection limits were calculated to be 0.16 ?mol L-1 for VP and 0.42 ?mol L-1 for OX. Good repeatabilities were obtained for 10 consecutives injections of these drugs, with relative standard deviation of 2.2% for VP and 0.94% for OX. The addition and recovery studies for VP and OX in pharmaceutical and urine samples were close to 100% and determination of VP was validated by the official methodology. High analytical frequencies were achieved by FIA system of 45 and 65 determinations per hour for VP and OX, respectively, using sampling handles less than 200 ?L and flow rate of 3.5 mLmin-1. The analysis of these drugs in urine showed that it is possible to determine this sample even in the presence of high concentrations of ascorbic acid and uric acid. Therefore, the present method by MPA-FIA proved to be a quick and easy alternative to quantify VP and OX in pharmaceutical formulations and urine.

A imobilização de moléculas de interesse biológico em superfícies sólidas é essencial para uma série de aplicações biotecnológicas. Dentre as técnicas de imobilização, a automontagem camada por camada por adsorção física possui inúmeras vantagens, incluindo condições brandas e fisiológicas de preparação, capacidade de incorporar diferentes biomoléculas, e controle molecular. Nesta tese foram explorados filmes nanoestruturados de materiais de interesse biológico, bem como modelos de membranas, em que foram empregadas a técnica de automontagem e a preparação de lipossomos. Os lipossomos, que serviram como modelos de membrana, foram imobilizados em filmes automontados e sua integridade estrutural foi mantida. Também foram utilizados para incorporar e estabilizar melanina, e então imobilizados em filmes automontados, com preservação da propriedade fluorescente da melanina. A automontagem também foi utilizada para imobilização das enzimas uricase, fitase e colesterol oxidase, alternadas com camadas de polieletrólitos. Estes filmes mostraram bom desempenho como biossensores amperométricos para uricase e fitase, e como biossensores usando espectroscopia de impedância para a fitase e colesterol oxidase. Tais biossensores foram usados para detectar baixas quantidades de ácido úrico, ácido fítico e colesterol, respectivamente. Não houve efeitos de interferentes nos sensores amperométricos devido à utilização de eletrodos previamente modificados com azul da Prússia, que funcionou como mediador redox. A alta sensibilidade e seletividade dos biossensores foram atribuídas à natureza do filme ultrafino e à capacidade de reconhecimento das biomoléculas, respectivamente. Esta abordagem abre caminho para novas tecnologias de dispositivos para diagnósticos clínicos e análises de alimentos, bem como para entender mecanismos de interação da biomolécula com a membrana celular para o desenvolvimento de agentes terapêuticos. / The immobilization of molecules of biological interest on solid surfaces is essential for a number of biotechnological applications. Among the techniques for immobilization the layer-by-layer (LbL) method based on physical adsorption exhibits several advantages, including mild, physiological conditions for film preparation, ability to incorporate different biomolecules and molecular control. In this thesis, nanostructured films made with materials of biological interest were exploited as model membranes, where use was made of the LbL technique and liposomes. The latter, which served as membrane models, were immobilized in LbL films and had their structural integrity preserved. Liposomes were also used to incorporate and stabilize melanin, which were then deposited on LbL films with the fluorescence of melanin being preserved. The LbL method was also used to immobilize the enzymes uricase, phytase and cholesterol oxidase, alternated with layers of polyelectrolytes. These LbL films were employed in amperometric biosensors with uricase and phytase, and in biosensors based on impedance spectroscopy for phytase and cholesterol oxidase. Low amounts of uric acid, phytic acid and cholesterol were detected, respectively. There was no effect from interferents in the amperometric biosensors because the electrodes were previously modified with a layer of Prussian Blue, which acted as a redox mediator. The high sensitivity and selectivity were attributed to the ultrathin nature of the films and the ability of molecular recognition of the biomolecules, respectively. The approaches used here open the way for novel devices for clinical diagnostics and food quality control, in addition to understanding the interaction mechanisms between the biomolecules and the cell membranes, which is important for developing therapeutic agents.

Este trabalho descreve a preparação e caracterização de eletrodos modificados com azul da Prússia e materiais relacionados e a sua aplicação na construção de biossensores enzimáticos amperométricos para a detecção de oxalato e de glicose. Os materiais utilizados na modificação dos eletrodos foram azul da Prússia e compostos híbridos formados por hexacianoferrato de níquel e polipirrol ou hexacianoferrato de cobre e polipirrol. Os materiais lubridos mostraram-se capazes de mediar na eletroredução de peróxido de hidrogênio, mesmo em eletrólitos contendo Na+, apresentando melhor desempenho analítico quando comparados aos respectivos hexacianoferratos sem a presença do polímero condutor. Estes materiais foram utilizados com êxito na construção de biossensores para oxalato e para glicose, imobilizando as enzimas Oxalato Oxidase e Glicose Oxidase, respectivamente. Também foi estudada a preparação de um biossensor para a detecção de glicose utilizando a técnica de automontagem eletrostática camada por camada. Esta técnica permite otimizar o processo de immobilização da enzima, obtendo excelente desempenho analítico com pouca quantidade de enzima. Finalmente, são apresentadas a síntese, caracterização e aplicação de nanopartículas de azul da Prússia na determinação de peróxido de hidrogênio. Foi possível preparar nanopartículas com um diâmetro médio de 5 nm, as quais foram imobilizadas em eletrodos mediante a técnica de automontagem eletrostática camada por camada, a fim de estudar seu comportamento eletroquímico. / This work describes the preparation and characterization of modified electrodes with Prussian blue and some analogues and their application in the development of amperometric enzymatic biosensors for the detection of glucose and oxalate. The materials used in electrode modification were Prussian blue and hybrid compounds, formed by nickel hexacyanoferrate and polypyrrole or copper hexacyanoferrate and polypyrrole. These materials were able to mediate the hydrogen peroxide electroreduction even in electrolytes containing Na+, showing better analytical performance than the hexacyanyoferrates without polypyrrole. These materials were successfully used to build up oxalate and glucose biosensors. We also have studied the preparation of glucose biosensors using the layer by layer self assemble technique (LBL), which has optimized the enzyme immobilization process, obtaining good analytical performances even loading small amounts of enzyme. FinaIly, we have described the synthesis and characterization of Prussian blue nanoparticles by a sonochemical method. It was possible to synthesize nanoparticles with a diameter around 5 nrn, which were immobilized by the LBL technique, in order to study their electrochemical behavior.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-05-09T15:10:00Z No. of bitstreams: 1 fernandadasilvanogueira.pdf: 2728835 bytes, checksum: 4d0c08d9506f20bb35bc5239101ac904 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-17T14:15:15Z (GMT) No. of bitstreams: 1 fernandadasilvanogueira.pdf: 2728835 bytes, checksum: 4d0c08d9506f20bb35bc5239101ac904 (MD5) / Made available in DSpace on 2017-05-17T14:15:15Z (GMT). No. of bitstreams: 1 fernandadasilvanogueira.pdf: 2728835 bytes, checksum: 4d0c08d9506f20bb35bc5239101ac904 (MD5) Previous issue date: 2016-09-08 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As estrobilurinas sintéticas são fungicidas produzidos e comercializados no mundo todo, estando entre os mais vendidos por sua eficiência contra diferentes fungos. Por razões de segurança de saúde pública, a ANVISA (Agência Nacional de Vigilância Sanitária) classifica as estrobilurinas sintéticas como produtos altamente ou medianamente tóxicos. Por isso, a legislação tem sido cada vez mais restritiva com relação aos agrotóxicos de modo geral, incluindo as estrobilurinas. O presente trabalho teve como objetivo o desenvolvimento de um método analítico para determinação de sete estrobilurinas por HPLC com detecção simultânea ultravioleta (UV) e eletroquímica/amperométrica (DE), além da sua aplicação na análise de amostras de feijão. O detector eletroquímico foi acoplado de modo “homemade” ao HPLC. O método de separação para as sete estrobilurinas por HPLC empregando coluna de fase reversa C 18 foi otimizado a partir do estudo de parâmetros como a composição da fase móvel e modo de eluição, avaliando-se, entre outros, a resolução e simetria dos picos. Para a detecção UV foi selecionado adequadamente o comprimento de onda, enquanto na detecção amperométrica o potencial de eletrólise, utilizando um eletrodo de diamante dopado com boro (DDB) como eletrodo de trabalho. A detecção UV foi realizada em 200 nm e a amperométrica aplicando-se um potencial de 1,9 V. Foi otimizado um método de extração para as estrobilurinas, o qual foi adequado, seletivo e eficiente na remoção de interferentes. Na avaliação da exatidão do método obteve-se valores de recuperações para as estrobilurinas entre 61,6 % a 98,8 % com desvios padrões menores que 10,0 %. Os limites de detecção do método foram 0,02 mg kg-1 para todas as estrobilurinas, e os limites de quantificação variaram de 0,06 a 0,07 mg kg1, obtidos por detecção UV e DE. Os métodos de detecção UV e DE também foram comparados estatisticamente, o que mostrou não haver diferenças significativas entre os resultados reportados por estes em um nível de 95 % de confiança. Foram analisadas sete amostras de feijão de diferentes tipos e procedência, todavia não foram detectadas nenhuma das estrobilurinas estudadas neste trabalho. / Synthetic strobilurins fungicides are produced and marketed all over the world, being among the best selling ones due to their efficiency against several fungi. For public health security reasons, ANVISA (National Health Surveillance Agency) classifies synthetic strobilurins as highly or moderately toxic. Therefore, legislation has been increasingly stricter regarding pesticides in general, including strobilurins. This study aimed to develop an analytical method for the determination of seven strobilurins using HPLC with simultaneous ultraviolet (UV) and electrochemical/amperometric (DE) detections, in addition to its application for the analysis of bean samples. The electrochemical detector was coupled to the HPLC in a homemade way. The separation method for the seven strobilurins by HPLC employing C18 reversed phase column was optimized from the study of such parameters as the composition of the mobile phase and the elution mode, evaluating, among others, peak resolution and symmetry. For UV detection the wavelength was suitably selected, while for the amperometric detection the potential electrolysis was chosen, using a boron-doped diamond electrode (DDB) as the working electrode. UV detection was performed at 200 nm and amperometric detection at 1.9 V. An extraction method was optimized for the strobilurins, which was adequate, selective and efficient in removing interfering substances. In the accuracy evaluation of the method, the recovery values obtained for strobilurins were between 61.6% and 98.8%, with standard deviations lower than 10.0%. The detection limits of the method were 0.02 mg kg -1 for all the strobilurins, and the quantification limits ranged from 0.06 to 0.07 mg kg-1, obtained by UV and DE detection. UV and DE detection methods were statistically compared, which showed no significant differences between the results reported by them at a 95% confidence level. Seven samples of bean of different types and origins were analyzed, but none of the strobilurins studied in this work were detected.