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Thesis (Ph. D.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains xii, 243 p. : ill. Vita. Includes abstract. Includes bibliographical references (p. 213-240).

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / BactÃrias do gÃnero Burkholderia possuem a capacidade de biodegradar inÃmeros compostos considerados poluentes. Mediante o exposto, este trabalho visou a identificaÃÃo molecular do isolado SMF042 oriundo de uma coleÃÃo de espÃcies de Burkholderia, verificar sua capacidade biodegradar o herbicida Ãcido 2,4-diclorofenoxiacÃtico (2,4-D), identificar as enzimas envolvidas neste processo por eletroforese bidimensional (2D) e a analisar a expressÃo dos genes tfdA e tfdB da via TFD de biodegradaÃÃo do 2,4-D. A fim de fazer a extraÃÃo de RNA e proteÃnas foi realizado o crescimento bacteriano em dois meios de cultivo BH (meio mineral), um controle, suplementado com glicose (600 mg/L), e outro suplementado com 2,4-D (600 mg/L). A extraÃÃo de RNA foi realizada na fase logarÃtmica enquanto a extraÃÃo de proteÃnas foi feita no inicio da fase estacionÃria de crescimento bacteriano. A partir das proteÃnas extraÃdas foi determinado o mapa bidimensional de referÃncia para cada condiÃÃo. O ajuste das imagens dos gÃis bidimensionais, a detecÃÃo de spots protÃico e a avaliaÃÃo dos dados para determinar variaÃÃes quantitativas e qualitativas, massa molecular (MW) e ponto isoelÃtrico (pI) dos spots foi feito pelo programa ImageMaster e a anÃlise da expressÃo dos genes, foi realizado por qRT-PCR empregando o mÃtodo da expressÃo relativa 2-ΔΔCT. Por meio da anÃlise do gene 16S rRNA o isolado SMF042 foi identificado como Burkholderia phymatum. No tocante a abordagem proteÃmica, o nÃmero mÃdio de spots das rÃplicas dos gÃis foi de 535 (controle) e 705 (tratado). A maior abundÃncia de proteÃnas foi observado nos gÃis na faixa de MW 20 e 40 KDa e pH 5-6. Enzimas envolvidas na biodegradaÃÃo do 2,4-D foram identificadas utilizando os valores de pI e MW do spot em comparaÃÃo com o banco de dados de proteÃnas no ExPASy, foram elas: 2,4-D alfa KG-dependente dioxigenase (tfdA) e clorocatecol 1,2-dioxigenase (tfdC) pertencentes a via TFD e 2,4-D oxigenase da via cadRABK, ambas de biodegradaÃÃo do 2,4-D. ProteÃnas envolvidas na resistÃncia ao estresse quÃmico, tambÃm foram identificadas, sendo elas: proteÃna GrpE e chaperona DnaK. O nÃvel de expressÃo do gene tfdA aumentou cerca de 23 vezes em relaÃÃo ao controle. Pelo exposto, o isolado SMF042 foi capaz de crescer em um meio contendo 2,4-D como Ãnica fonte de carbono, expressou proteÃnas de vias de biodegradaÃÃo do 2,4-D, resistÃncia ao estresse quÃmico e aumentou a expressÃo gÃnico de tfdA, o que indica a importÃncia desta bactÃria na biodegradaÃÃo deste poluente. / Burkholderia bacteria it has ability to biodegrade pollutants considered numerous compounds. By the above, this study aimed to identify molecular SMF042 come from an isolated collection of Burkholderia species, verify their ability to biodegrade the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), to identify the enzymes involved in this process by electrophoresis two-dimensional (2D) and to analyze the expression of genes and TFDA tfdB track TFD biodegradation of 2,4-D. In order to make the extraction of RNA and protein bacterial growth was performed in two culture media BH (mineral medium), a control supplemented with glucose (600 mg / L) and another supplemented with 2,4-D (600 mg / L). RNA extraction was performed in the logarithmic phase while protein extraction was done at the beginning of the stationary phase of bacterial growth. The extracted proteins from two-dimensional map was determined for each reference condition. The adjustment of images of two-dimensional gels, the protein spot detection and evaluation of data to determine quantitative and qualitative changes, molecular weight (MW) and isoelectric point (pI) of the spots was made by the ImageMaster software and analysis of gene expression was qRT-PCR performed by using the method of relative expression 2-ΔΔCT. Through the analysis of the 16S rRNA isolate SMF042 was identified as Burkholderia phymatum. Regarding proteomics approach, the average number of spots of the replicas of the gels was 535 (control) and 705 (treated). The most abundant protein in the gels was observed in the range of 20 and 40 MW kDa and pH 5 and 6. Enzymes involved in the biodegradation of 2,4-D were identified using the values of pI and MW of spot against a database of proteins at ExPASy, they were: 2,4-D alpha KG-dependent dioxygenase (TFDA) and chlorocatechol 1 ,2-dioxygenase (tfdC) belonging saw PDT and 2,4-D oxygenase pathway cadRABK, both biodegradation of 2,4-D. Proteins involved in resistance to chemical stress, have also been identified, which are: protein chaperone DnaK and GrpE. The level of gene expression TFDA increased about 23 times compared to control. As shown, the isolated SMF042 was able to grow on a medium containing 2,4-D as sole carbon source expressed protein degradation pathways of 2,4-D, resistance to chemical stress and increased expression of gene TFDA, which indicates the importance of this bacterium in this pollutant biodegradation.

The potential human health issues resulting from the continuous consumption of drinking water containing low concentration levels of persistent emerging pollutants has raised some concerns. The presence of emerging pollutants in surface water bodies and ground-water in Canada together with absence of proper drinking water treatment processes in remote places has created the need for an effective and simple process for removal of emerging pollutants from drinking water. Low seasonal temperatures in regions such as Saskatchewan demand a removal process that is effective at temperatures lower than room temperature. Adsorption with granular activated carbon is a well-established and effective method for removal of organic compounds from drinking water. There are a large number of reports on removal of organic compounds by activated carbon in literature however, the effectiveness of adsorption of emerging pollutants with granular activated carbon is not clear. Effectiveness of ozone treatment for oxidation of emerging pollutants is reported in literature however, effectiveness of regeneration of adsorbents saturated with emerging pollutants with ozone has not been investigated extensively. In the present work, effectiveness of adsorption with granular activated carbon for removal of emerging pollutants is investigated. Three model compounds of Ibuprofen, 2,4-dichlorophenoxyacetic acid, and Bisphenol A reported at considerable concentration levels in Saskatchewan water bodies were selected as model compounds. Bituminous coal based and coconut shell based granular activated carbons with basic point of zero charge were selected as adsorbents. Isotherm adsorption of model compounds on adsorbents was conducted at 280, 288, and 296 K. The Gibbs free energy, enthalpy, and entropy of adsorption were calculated using isotherm model parameters. Nitric acid pre-treatment was applied to reduce the point of zero charge of adsorbents. Adsorption isotherms were conducted with the acid treated adsorbents. Adsorption removal of model compounds in tap water was studied. Effectiveness of regeneration of saturated adsorbents with ozone was investigated. In terms of quality of fit to the isotherm adsorption data, Langmuir model was better than Freundlich model indicating monolayer adsorption of model compounds in all experiments. Higher Langmuir monolayer adsorption capacity (Qmax) of bituminous coal based adsorbent than coconut shell adsorbent for adsorption of model compounds was attributed to the higher porosity of bituminous coal based adsorbent. Adsorption of model compounds (i.e. IBP and BPA) present in molecular form in the pH condition of the experiments were more dependent on adsorbent surface functional groups e.g. carboxyl and carbonyl groups. The Qmax of adsorption of 2,4-D present in anionic form was proportional with the specific surface area of adsorbent. Adsorption at temperatures lower than room temperature was effective. Adsorbent with acidic point of zero charge was more effective in removal of model compounds than adsorbent with basic point of zero charge. Adsorption of BPA was higher in tap water in comparison to Millipore water due to the more neutral surface of adsorbent in tap water. Higher pH of tap water than Millipore water and the ionic interaction between the adsorbent and dissolved solids present in tap water caused the more neutral surface of adsorbent. Regeneration of adsorbents with ozone failed in restoration of adsorption capacity of adsorbents and excessive ozonation destroyed the pore structure of adsorbents.

Orientador: Rodnei Bertazzoli / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-07T06:34:47Z (GMT). No. of bitstreams: 1 Badellino_Carla_M.pdf: 4439168 bytes, checksum: 0e434b627394c712d54234bcc01ad717 (MD5) Previous issue date: 2006 / Resumo: Nest trabalho foi investigada a desempenho do peróxido de hidrogênio eletrogerado a partir de redução do oxigênio na superfície de um catodo de carbono vítreo reticulado para a oxidação do herbicida ácido 2,4-diclorofenoxiacético. Inicialmente, foram feitas voltametrias cíclicas para verificar se o 2,4-D para verificar a existência de pares redox. O eletrólito suporte usado foi o K2SO4 0,3 mol L-1, pH 10, em meio saturado de N2. Após a verificação da ausência de reação redox para o 2,4-D, fez-se a otimização da eletrogeração de peróxido de hidrogênio. Usando como catodo um eletrodo rotatório cilíndrico de carbono vítreo reticulado de 60 ppi e um anodo de platina, em meio de K2SO4 0,3 mol L-1, pH 10, saturado com O2 e 900 rpm, determinou-se que o melhor potencial para eletrogeração de H2O2 foi de ¿ 1,6 V vs. ECS a uma temperatura de 8 0C. Em etapa subseqüente, verificou-se a degradação do herbicida 2,4-D em solução, na concentração de 100 mg L-1 por diferentes três processos: H2O2 eletrogerado, UV/H2O2, e fotoeletro-Fenton, este último realizado em pH 2,5. Para tanto foram feitas injeções no Cromatógrafo Líquido de Alta Eficiência, além de análise de Carbono Orgânico Total e Demanda Química de Oxigênio. Dos processos estudados, o mais vantajoso foi o catalisado com radiação UV e sais de Fe2+ (Reagente de Fenton), com uma redução do COT de 69 % do valor inicial. Dando continuidade os estudos, foi construído um reator em escala piloto do tipo filtro prensa com fluxo transversal para eletrogeração de peróxido de hidrogênio. Composto por dois compartimentos anódicos e um catódico, separado por membranas catiônicas Nafion ®N242, o reator foi otimizado em três diferentes parâmetros: o potencial de trabalho, a velocidade de vazão do fluido e a vazão de oxigênio. Os valores ótimos encontrados para eletrogeração de H2O2 em eletrólito suporte de K2SO4 0,3 mol L-1 foram: potencial de -1,6 V vs. Pt, velocidade do fluido de 500 L h-1 e vazão de oxigênio de 6 L s-1. Com o reator otimizado e acumulando cerca de 1100 mg L-1 de H2O2 em 5 horas de processo, foram feitos ensaios de degradação do 2,4-D em seis deferentes métodos: dois ensaios em meio básico com e sem incidência de radiação ultravioleta, e em seguida, mais quatro ensaios em meio ácido, também com e sem a incidência de radiação ultravioleta, na presença do reagente de Fenton, e por fim, um ensaio catalisado com radiação ultravioleta e na presença do reagente de Fenton. Os ensaios em meio ácido e catalisado, mais uma vez se mostraram mais eficientes e a remoção do COT seguiu uma cinética de pseudo-primeira ordem. Mesmo não havendo muita variação no tempo de degradação o gráfico de ln[C(t)/C(0)] vs. tempo, mostra que o processo mais vantajoso é aquele catalisado com UV/Fenton, com uma constante de redução do COT uma ordem de grandeza maior do que para o processo apenas com incidência de radiação UV. Os valores foram, respectivamente, 9,4x10-5 s-1 e 1,75x10-4 s / Abstract: In this work, the performance of the H2O2 electrogeneration process from O2 reduction on a reticulated vitreous carbon cathode was investigated. The process was also use for the oxidation of the herbicide 2,4-dichlorophenoxyacetic acid. Firstly, cyclic voltammetries were used for the identification of possible reduction reactions of the herbicide. The supporting electrolyte used was a 0,3 mol L-1 K2SO4, pH 10, nitrogen saturated solution. Then, the optimization of hydrogen peroxide electrogeneration it was carried out. As a cathode, a reticulated vitreous carbon-rotating cylinder, shaped from a 60 ppi RCV plate was used. A platinum foil was used as anode and a saturated calomel electrode was used as reference. Supporting electrolyte was always K2SO4 0,3 mol L-1, in an O2 saturated solution. The experiments were run in a 150 mL electrode cell, with a water jacket to keeping temperature in the range from 8 0C. The best potential to produce hydrogen peroxide in these conditions was -1,6 V vs. SCE. In following stage, the degradation of 2,4-D was investigated by tree different process: H2O2 electrogenerated, H2O2/UV and photo electro-Fenton being the last at pH 2,5. The degradation of 2,4-D was followed by HPLC, moreover TOC and COD analyses. The most efficient process was the catalyzed UV/Fe2+ process that presented a TOC reduction of 69 %. In a sequence, a pilot scale reactor was mounted for hydrogen peroxide electrogeneration. The reactor is formed by two anolytes and one catholyte compartments, separated by a N424 Nafion® membrane. The reactor was optimized considering three different parameters: the applied potential, oxygen flow and the electrolyte flow. Best operational parameters electrogeneration rate of hydrogen peroxide in a K2SO4 0,3 mol L-1 electrolyte support were: -1,6 V vs. Pt, 500 L h-1 of electrolyte flow and 6 L s-1 of oxygen flow. Considering these results, the experiments for the degradation of 2,4-D were conducted with the optimized reactor. In this new series of experiments, six different processes were tested. In alkaline medium, the degradation occurred only with H2O2 and H2O2, catalyzed by UV radiation. Four processes were used in acidic medium: H2O2, H2O2 catalyzed by UV radiation, Fe2+ (electro Fenton process) and H2O2 with Fe2+ catalyzed by UV radiation (photo-electro Fenton process). In catalyzed experiments in acidic medium, degradation rates were higher TOC decay presented a pseudo-first order kinetic. The differences between electro Fenton and photo-electro Fenton processes appeared only when TOC reduction was considered. A greater degree of organics combustion was observed for the last process, with 95 % of TOC was eliminated. / Mestrado / Engenharia de Materiais / Mestre em Engenharia Mecânica

Made available in DSpace on 2017-07-21T20:43:46Z (GMT). No. of bitstreams: 1 Sabrina Marinho Kaplun.pdf: 2639962 bytes, checksum: a9f7e8225e77abb24e8a18b7dd472300 (MD5) Previous issue date: 2015-04-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The purpose of this study was to obtain, characterize and evaluate the photocatalytic activity of the surface modified titanium dioxide in relation to the unmodified titanium dioxide. Titanium dioxide (TiO2) anatase (commercial) was introduced into an oven made, with the function of modifying the external surface of the oxide by the effect of pressure, temperature and time. The modified titanium (TM) oxides and unmodified (TN) were characterized by the techniques of X-ray diffraction (XRD)and refinement by the Rietveld method, transmission electron microscopy (TEM) and determination of specific surface area. In heterogeneous photodegradation tests, degradation of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) was accompanied by UV/vis, high performance liquid chromatography efficiency (HPLC) and determination of total organic carbon (TOC). The influence of pressure on the surface of titanium dioxide resulted in a change in the external surface of titanium dioxide, surface irregularities increases, without changes in unit cell parameters and increases the surface area. The photocatalytic activity of the modified titanium dioxide (TM) was higher to the unmodified titanium dioxide (TN).The modified titanium dioxide had a higher percentage of degradation of the herbicide 2,4-dichlorophenoxyacetic acid and a higher mineralization making it more efficient. / A proposta desse trabalho consistiu em obter, caracterizar e avaliar a atividade fotocatalítica do dióxido de titânio modificado superficialmente em relação ao dióxido de titânio não modificado. O dióxido de titânio (TiO2) anatase (comercial) foi introduzido em um forno confeccionado, com a finalidade de modificar a superfície externa do óxido de titânio pelo efeito da pressão, temperatura e tempo. Os óxidos de titânio modificados (TM) e não modificados (TN) foram caracterizados pelas técnicas de difração de raios X (DRX) e refinamento pelo método de Rietveld, microscopia eletrônica de transmissão (MET) e determinação da área superficial específica. Nos ensaios de fotodegradação heterogênea, a degradação do herbicida 2,4-diclorofenoxiacético (2,4-D) foi acompanhada pelas técnicas de UV/vis, cromatografia líquida de alta eficiência (HPLC) e determinação de carbono orgânico total (COT). A influência da pressão na superfície do dióxido de titânio resultou em uma modificação na superfície externa do dióxido de titânio aumentando irregularidades na superfície, sem alterações nos parâmetros da célula unitária e com elevação da área superficial. A atividade fotocatalítica do dióxido de titânio modificado (TM) foi superior ao dióxido de titânio não modificado (TN). O dióxido de titânio modificado apresentou maior porcentagem de degradação do herbicida 2,4-diclorofenoxacético e uma maior mineralização o que o torna mais eficiente.

Inspired by natural catalytic systems, metalloporphyrins and Salen complexes have been used as catalysts for the oxidation of xenobiotics in the presence of several oxygen donors, both in homogeneous and heterogeneous catalysis. These catalysts have been highly efficient and selective in the reactions of different substrates, such as pharmaceuticals and pesticides. In this context, the work developed in this dissertation presents the oxidation studies of 2,4-dichlorophenoxyacetic acid herbicide using ferroporphyrins and Jacobsen catalyst as catalysts of these reactions with several oxygen donors. The results shows that the metalloporphyrin and the complex employed in this study are efficient catalysts for oxidation of 2,4-D in the presence of oxygen donors iodosilbenzene (PhIO), metachloroperbenzoic acid (m-CPBA) and hydrogen peroxide (H2O2) both in homogeneous and heterogeneous. The reactions with the unsupported catalysts achieved higher yields than those obtained with the supported catalysts, which is possibly related to the difficulties of access to the catalytic center imposed by the support. The conversion of 2,4-D reached more than 50% in some systems, and, in general, oxidation reactions with the three oxygen donors were selective promoting the formation of hydroquinone (reactions with PhIO and H2O2) and 3,5- dichlorocatechol (reactions with m-CPBA). One of the products identified in the reactions is a metabolite of 2,4-D produced in vivo systems, indicating that the catalysts used in this study can be considered good models of cytochrome P450 in the oxidation of 2,4-D. / Inspirados em sistemas catalíticos naturais, metaloporfirinas e complexos salen têm sido utilizados como catalisadores para a oxidação de xenobióticos na presença de diversos doadores de oxigênio, tanto em catálise homogênea quanto heterogênea. Esses catalisadores têm se mostrado altamente eficientes e seletivos nas reações de diferentes substratos, tais como fármacos e pesticidas. Dentro desse contexto, o trabalho desenvolvido nessa dissertação apresenta os estudos da oxidação do herbicida ácido 2,4-diclorofenoxiacético (2,4-D) utilizando ferroporfirinas e catalisador de Jacobsen como catalisadores dessas reações com diversos doadores de oxigênio. Os resultados mostram que a metaloporfirina e o complexo salen empregados nesse estudo são eficientes catalisadores para a oxidação do 2,4-D na presença dos doadores de oxigênio iodosilbenzeno (PhIO), ácido metacloroperbenzóico (m-CPBA) e peróxido de hidrogênio (H2O2), tanto em meio homogêneo como heterogêneo. As reações com os catalisadores não suportados alcançaram rendimentos mais altos do que os obtidos com os catalisadores suportados, o que está possivelmente relacionado as dificuldades de acesso ao centro catalítico imposta pelo suporte. A conversão de 2,4-D atingiu mais de 50% em alguns sistemas, e, em geral, as reações de oxidação com os três doadores de oxigênio foram seletivas promovendo a formação de hidroquinona (reações com PhIO e H2O2) e 3,5-diclorocatecol (reações com m-CPBA). Um dos produtos identificados nas reações é um metabólito do 2,4-D produzido sistemas in vivo, indicando que os catalisadores utilizados nesse estudo podem ser considerados bons modelos do citocromo P450 na oxidação do 2,4-D.

Aujourd'hui, avec l'augmentation de la population, la consommation de médicaments et de produits phytosanitaires dans l'agriculture a considérablement augmenté. Cela devient inquiétant car une grande partie de ces molécules, rejetée dans l'environnement, ne sont pas bien éliminées par les stations d'épuration (lorsqu'elles existent). En trop grande quantité, ces produits deviennent des poisons pour tous les organismes vivants, y compris l’Homme.Des méthodes analytiques classiques pour la mesure de ces produits chimiques existent déjà (méthodes séparatives classiques telles que la chromatographie en phase gazeuse, la chromatographie liquide à haute performance, éventuellement couplée à la spectrométrie de masse, etc.). Cependant, même si elles sont extrêmement précises et fiables, ces techniques sont difficiles à appliquer pour la surveillance sur site et sont généralement coûteuses. Pour cette raison, ma thèse se concentre sur de nouvelles approches analytiques pour détecter de petites molécules en milieu aqueux, telles que ces polluants. Dans une première partie de mon travail, j’ai développé un immunocapteur basé sur une complexation compétitive originale et sur une transduction électrochimique (ampérométrique), pour la détection du diclofénac, un anti - inflammatoire non stéroïdien généralement utilisé pour réduire l’inflammation et soulager la douleur. L'électrode de travail a été fonctionnalisée par deux sels de diazonium, l'un utilisé comme sonde moléculaire (un dérivé du diclofénac couplé à une arylamine) et l'autre comme sonde redox (une quinone) également couplée à une arylamine, capable de transduire l'association haptène-anticorps par une variation de son électroactivité ; en particulier, la transduction a été conçue pour délivrer une augmentation de courant lors de la détection du diclofénac (soit une détection « signal-on »). J’ai montré une limite de détection d’environ 20 fM dans l'eau du robinet, ce qui rend ce type de capteur très compétitif. Dans la suite de mon travail, j'ai conservé la même approche de transduction originale (immunoreconnaissance compétitive) mais appliquée à un transistor à effet de champ organique à grille électrolytique (EGOFET) dont le semiconducteur est le poly (N-alkyldiketopyrrolo-pyrrole dithiénylthiéno [3,2-b ] thiophène) (DPP-DTT) et dont l'électrode de grille a été fonctionnalisée par électrogreffage d'un sel de diazonium fonctionnel capable de lier un anticorps spécifique de l'acide 2,4-dichlorophénoxyacétique (2,4-D), un herbicide courant. Le design de la sonde moléculaire a été rationalisée par modélisation moléculaire afin d’optimiser la capture de l’anticorps en surface de grille. Dans la dernière partie de mon travail, je propose une approche qui met à profit à la fois le couplage capacitif de l'EGOFET mais aussi sa sensibilité aux charges électrostatiques accumulées en surface de grille. J'ai immobilisé en surface de grille un peptide court (Gly-Gly-His) connu pur avoir une forte affinité envers les ions cuivre Cu2+. Le peptide a été immobilisé par électro-oxydation directe de l'amine primaire du premier fragment glycine. J’ai démontré que les dispositifs EGOFET, modifiés par GGH, peuvent transduire la complexation de Cu2+ par des variations significatives de leurs caractéristiques de sortie et de transfert, en particulier par un décalage de la tension de seuil (VTh). / Today, with the increase of population, the consumption of drugs and of chemicals in agriculture has dramatically increased. It becomes a worrisome issue because a large amount of these molecules, excreted to the environment, are not well eliminated by water-treatment plants (when they exist) and are therefore released without control into the ecosystem. In too large quantities, these drugs are poisons for living organisms, including humans. Classical analytical methods for the measurement of these chemicals already exist (classical separative methods such as gas chromatography, high-performance liquid chromatography, possibly coupled with mass spectrometry, etc). However, even if extremely precise and reliable, these techniques are difficult to apply for on-site monitoring and are usually costly. For this reason, my thesis focuses on novel analytical approaches to detect small organic molecules such as these pollutants. In a first part of my work, I developped an original immunosensor based on a competitive complexation and on an electrochemical (amperometric) transduction, for detection of diclofenac, which is a non – steroidal anti – inflammatory drug generally employed to protect patients from inflammation and relieve pain. The working electrode was electrografted with two functional diazonium salts, one as molecular probe (a diclofenac derivative coupled with an arylamine) and the other as redox probe (a quinone) also coupled with an arylamine, able to transduce the hapten-antibody association into a change in electroactivity. The transduction was designed to deliver a current increase upon detection of diclofenac (“signal-on” detection). The detection limit is ca. 20 fM in tap water, which is competitive compared to other label-free immunosensors. In the following part of my thesis, I kept the same original transduction approach (competitive immunoassay) but applied to an Electrolyte-Gated Organic Field-Effect Transistor (EGOFET) based on poly(N-alkyldiketopyrrolo-pyrrole dithienylthieno[3,2-b]thiophene) as organic semiconductor whose gate electrode was functionalized by electrografting a functional diazonium salt capable to bind an antibody specific to 2,4-dichlorophenoxyacetic acid (2,4-D), an herbicide well-known to be a soil and water pollutant. Molecular docking computations were performed to design the functional diazonium salt to rationalize the antibody capture on the gate surface. In the last part of my work, I propose an approach which takes profit not only of the capacitive coupling of the EGOFET but also on its sensitivity to electrostatic charges accumulated on the gate surface. To illustrate this in the field of sensors, I used a short peptide (Gly-Gly-His), known to selectively bind copper ions Cu2+. The peptide was immobilized by direct electrooxidation of the primary amine of the first glycine moiety. I demonstrated that GGH-modified EGOFETs can transduce Cu2+ complexation through significant changes of their output and transfer characteristics, in particular their threshold voltage (VTh).