Orientador: Douglas Soares Galvão / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-31T07:27:10Z (GMT). No. of bitstreams: 1 Moura_FranciscoAlirioAlmeidaGomesDe_D.pdf: 33020380 bytes, checksum: e40379018df214dbad74041d1e5f6b3e (MD5) Previous issue date: 2016 / Resumo: Esse documento apresenta uma coleção de trabalhos realizados dentro do amplo campo de materiais nanoestruturados, focando-se em descrições teóricas analíticas e simulações computacionais de diversos novos materias desse tipo. Uma nova fibra supereslástica e condutora é reportada. Essa fibra altamente esticável (até 1320%) é criada envolvendo-se um núcleo cilíndrico de borracha com uma camada de folha de nanotubos de carbono. O material resultante exibe uma interessante estrutura de enrugamentos hierárquicos na sua superfície, o que lhe garante propriedades elétricas úteis como conservar a sua resistencia constante enquanto esticada. Adicionando-se mais camadas de borracha ou nanotubos podemos obter aplicações como sensores de movimento ou deformação, atuadores/músculos artificiais ativados por corrente ou temperatura e operados reversivelmente por um mecanismo de acoplamento entre tensão e torção. Nós explicamos suas propriedades de condução elétrica e os fenômenos físicos envolvidos em cada uma dessas aplicações. Também desenvolvemos um novo método para o desenho racional de polímeros molecularmente impressos usando dinâmica molecular para simular o processo de impressão molecular e a análise subsequente utilizando experimentos de cromatografia simulada. Obtivemos com sucesso a primeira evidência teórica do mecanismo de impressão exibindo afinidade e seletividade para a substância alvo 17-beta-estradiol. Desenhamos e simulamos uma nova estrutura com formato de piramide em kirigami de grafeno, composta de uma folha de grafeno cortada em um padrão específico a fim de formar uma pirâmide quando sofre tensão na direção normal ao plano. Nós calculamos a resposta dessa estrutura a uma carga estática, quando ela age como uma mola de proporções nanométriacs. Também, utilizando simulações de dinâmica molecular de colisões balísticas, constatamos que a resistência desse material a impactos é ainda maior que de uma folha de grafeno puro, sendo ainda mais leve. Um novo método de reforçar fios de nanotubos de carbono, chamado ITAP, também é reportado. Esse método foi capaz de melhorar a resistencia mecanica do fio em até 1,5 vezes e torná-lo muito mais resistente ao ataque de ácido quando comparado com um fio não tratado. Utilizamos simulações de dinâmica molecular para testar a hipótese de que esse tratamento é suficiente para gerar ligações covalentes entre as paredes externas de nanotubos diferentes, o que seria responsável pelas propriedades do material. Aplicamos um algoritmo genético modificado ao problema do folding de proteínas em um modelo de rede 3D HP. Testamos o algoritmo utilizando um conjunto de sequencias de teste que têm estado em uso pelos últimos 20 anos na literatura. Fomos capazes de melhorar um dos resultados e demonstramos a aplicação e utilidade de operadores não canônicos que evitam a convergência prematura do algoritmo, sendo eles o operador de compartilhamento e efeito maternal / Abstract: This document presents a colection of works done within the broad subject of nano-structured materials, focusing on analytical theoretical descriptions and computational simulations of new kinds of this class of materials. A new superelastic conducting fiber is reported, with improved properties and functionalities. They are highly stretchable (up to 1320%) conducting fibers created by wrapping carbon nanotube sheets on stretched rubber fiber cores. The resulting structure exhibited an interesting hierarchical buckled structure on its surface. By including more rubber and carbon nanotube layers, we created strain sensors, and electrically or thermally powered tensile and torsional muscles/actuators operating reversibly by a coupled tension-to-torsion actuation mechanism. We explain its electronic properties and quantitatively explain the compounded physical effects involved in each of these applications. We also developed a new method for the rational design of molecularly imprinted polymers using molecular dynamics to simulate the imprinting process and subsequent chromatography studies. We successfully obtained the first theoretical evidence of actual imprinting happening under unconstrained simulations showing affinity and selectivity to the target substance 17-beta estradiol. We designed and simulated a new graphene kirigami pyramid structure, composed of a cut graphene sheet in a specific pattern in order to form a pyramid when under stress perpendicular to the plane. We calculated the response to static loading of this structure that acts like a nano-sized spring. Also, with simulated ballistic collisions we obtained increased resistance to impact in comparison with a pure graphene sheet. A new method of strengthening carbon nanotube yarns, called ITAP, consisting of annealing at high temperature in vacuum is reported. This method is shown to increase the mechanical resistance of the wire up to 1.5 times and make it much more resistant to acid corrosion when compared to pristine non-treated wires. We applied a modified genetic algorithm to the protein folding problem using an 3D HP lattice model using known test sequences that have been in use for the last 20 years and obtained an improvement for the best solution found for one of these proteins. Also, the importance of new non-canonical operators that prevent rapid convergence of the algorithm was demonstrated, namely the Sharing and Maternal Effect operators / Doutorado / Física / Doutor em Ciências / 141198/2012-5 / CNPQ

No description available.

Avec une limite de détection ultime pouvant atteindre le yoctogramme (1 yg = 10-24 g), les nanosystèmes électromécaniques (NEMS) employés comme capteurs gravimétriques présentent un fort potentiel pour la détection ultra-sensible et sans marquage de molécules biologiques. A l’heure actuelle, plusieurs défis restent cependant à relever avant de pouvoir envisager de manière réaliste leur utilisation comme outils de biodétection. Ces travaux de thèse adressent en particulier l’intégration du moyen de transduction et le développement de stratégies de biofonctionnalisation. En vue de répondre à la première problématique, l’intégration d’une couche piézoélectrique à base de Titano-Zirconate de Plomb (PZT) selon une approche de fabrication collective de réseaux de NEMS par voie descendante a été développée et caractérisée.Deux approches de biofonctionnalisation adaptées à une organisation de NEMS en réseaux,respectivement basées sur le dépôt localisé de matériel biologique par impression moléculaire et sur la structuration par photolithographie d’une couche bioréceptrice à base de polymères à empreintes moléculaires (MIP), ont ensuite été mises en oeuvre et ont permis de démontrer une première preuve de concept. Ces différentes contributions constituent un premier pas dans le développement des NEMS pour des applications de biodétection. / With an ultimate limit of detection down to the yoctogram regime (1 yg = 10-24 g),nanoelectromechanical systems (NEMS) resonators used as ultra-sensitive and label-free gravimetric sensors have a high potential for biodetection applications. To date, several challenges currently limit their wide spread use as viable biosensing tools. This PhD thesis addresses the issues related to the transducer integration and the biofunctionnalization. A Lead Zirconate Titatane (PZT)-based piezoelectric transducer has been implemented according to a top-down approach compatible with collective fabrication of NEMS arrays. Two biofunctionnalization strategies, suitable for a NEMS array organization and based on the localized deposition of biological material assisted by microcontact printing and the patterning of molecularly imprinted polymers (MIP) by photolithography, have also been investigated and first proof-of-concept biosensors were demonstrated. These various contributions have the potential to drive future advancements in the realm of NEMS as effective biosensing tools.

Ein aktueller Forschungsschwerpunkt in der analytischen Chemie ist die Entwicklung (bio)chemischer Sensoren mit hoher Selektivität, Empfindlichkeit und schnellem Ansprechverhalten für den Nachweis und das Monitoring von besorgniserregenden Analyten in Realproben. Fluoreszierende molekular geprägte Sensormaterialien bieten einen innovativen Ansatz, indem sie die spezifischen Erkennungsfähigkeiten molekular geprägter Polymere (MIPs) mit der hohen Empfindlichkeit der Fluoreszenzdetektion kombinieren. Ziel dieser Arbeit war es, MIPs mit optischen Sensoreigenschaften zu entwickeln, um Umweltschadstoffe schnell und spezifisch nachzuweisen. Zur Konstruktion von MIPs mit außergewöhnlichen optischen Eigenschaften wurden fluoreszierende Sonden-Monomere auf Basis des Bor-Dipyrromethen (BODIPY)-Fluorophors entwickelt, synthetisiert und charakterisiert. Verschiedene Akzeptor-Einheiten wurden in das BODIPY-Gerüsts eingeführt, um das Ansprechverhalten auf Zielanalyten mit Carboxylatfunktionen (z.B. Arzneimittelwirkstoffe, Pestizide, oberflächenaktive Substanzen) zu untersuchen. Diese fluoreszierenden Sonden-Moleküle wurden mit polymerisierbaren Einheiten ausgestattet, um ihre kovalente Einbindung in ein quervernetztes MIP-Netzwerk zu ermöglichen, das als Erkennungselement und Signalübermittler dient. Die Molekülstrukturen wurden durch Röntgenkristallanalyse bestätigt. Mit Hilfe spektroskopischer Methoden wurden die photophysikalischen Eigenschaften der Sonden-Monomere und ihre Bindungsaffinität für die Zielmoleküle untersucht, wobei die Sonden-Monomere eine starke Fluoreszenz im sichtbaren bis nahen Infrarotbereich aufwiesen und bemerkenswerte spektrale Veränderungen bei der Bindung mit den Zielanalyten zeigten. Der Einbau der Sonden in MIP-Schalen auf Siliziumdioxid-Kernpartikeln ermöglichte den selektiven Nachweis eines bestimmten Antibiotikums gegenüber anderen Antibiotika mit ähnlichen funktionellen Gruppen. Weiterhin wurden rot-emittierende BODIPY-Farbstoffe zur Dotierung von Polymerkernen eingesetzt, um ein Sensorsystem mit dualer Emission (d. h., mit Farbstoff dotierter Polymerkern/SiO2-Schale/fluoreszierendes Sonden-Monomer enthaltende MIP-Schale). Diese sensorischen MIPs zeigten eine ratiometrische Fluoreszenzantwort auf ein Antihistaminikum, wobei das eingebaute Referenzsignal im Kern eine Selbstkalibrierung in den Assays ermöglichte. Ein weiteres dual fluoreszierendes MIP-Sensormaterial (d. h. farbstoffdotierter Siliziumdioxidkern/fluoreszierendes Sonden-Monomer enthaltende MIP-Schale) wurde für die direkte Messung von Perfluorcarbonsäuren entwickelt. Die Integration der sensorischen MIPs in einen mikrofluidischen Aufbau führte zu einer mobilen und vielseitigen Sensorplattform, die einfach zu bedienen ist. / One of the current focal points of research in the field of analytical chemistry is the development of (bio)chemical sensors with high selectivity, sensitivity, and rapid response for the detection and monitoring of analytes of high concern in complicated samples. Fluorescent molecularly imprinted sensor materials represent a cutting-edge approach to developing sensors that combine the specific recognition capabilities of molecularly imprinted polymers (MIPs) with the high sensitivity of fluorescence detection. The objective of this thesis was to design, synthesize, and evaluate MIPs with optical sensing properties, focusing mainly on fluorescence, with the aim of rapidly and specifically detecting emerging environmental contaminants. To construct MIPs with exceptional optical characteristics and a well-defined binding mechanism for the recognition of target molecules, a series of tailor-made fluorescent probe monomers based on the boron-dipyrromethene (BODIPY) fluorophore have been designed, synthesized and characterized. Identical acceptor modules were introduced at various positions, or different acceptor modules were introduced at the same position of the BODIPY scaffold, to preliminarily investigate the response behavior of different types of probe monomers for target analytes containing carboxylate functions, ranging from pharmaceuticals to pesticides and surfactants. Additionally, one or two polymerizable units were attached to these fluorescent probe molecules to enable their covalent incorporation into a crosslinked MIP network, serving as recognition element and signal transducers. The molecular structures of these probe monomers were confirmed via X-ray crystal analysis. Spectroscopic approaches were employed to assess the photophysical characteristics of the probe monomers and their binding affinities for the target molecules. These probe monomers exhibited strong fluorescence in the visible-to-near infrared wavelength region, along with remarkable spectral changes upon binding with the target analytes. Incorporation of the fluorescent probes into MIP shells on silica cores achieved selective detection of a targeted antibiotic from other antibiotics with similar carboxylate, amine and aromatic functional groups. In addition, the synthesis of red-emitting BODIPY dyes for doping into polymer cores facilitated the fabrication of a dual-emission sensing system (i.e., dye-doped polymer core/silica shell/MIP shell). The sensory MIPs exhibited a ratiometric fluorescence response to an antihistaminic drug and the presence of a built-in reference signal in the core provided self-calibration for MIP assays. Furthermore, another dual-fluorescent MIP sensor material was engineered (i.e., dye-doped silica core/MIP shell) for the direct monitoring of perfluorocarboxylic acids. The integration of the sensory MIPs into a dedicated microfluidic setup resulted in a portable and easy-to-operate versatile sensing platform.

Measuring urinary tobacco specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronide conjugate may provide the best biomarker of tobacco smoke lung carcinogen metabolism. Existence of differences in the extent of NNAL metabolism rates may be potentially related to an individuals’ lung cancer susceptibility. Low concentrations of NNAL in smokers urine (<1 ng/mL) require sensitive and selective methods for analysis. Traditionally, this involves extensive, time-consuming sample preparation that limits throughput and adds to measurement variability. Molecularly imprinted polymers (MIPs) have been developed for the analysis of urinary NNAL by offline cartridge extraction combined with LC-MS/MS. This method when reproduced demonstrated problems with matrix effects. In the first part of this work, investigation of matrix effects and related problems with sensitivity for the published offline extraction method has been conducted. In order to address the need to improve throughput and other analytical figures of merit for the original method, the second part of this work deals with development of a high-throughput online microfluidic method using capillary-columns packed with MIP beads for the analysis of urinary NNAL. The method was validated as per the FDA guidance, and enabled low volume, rapid analysis of urinary NNAL by direct injection on a microfluidic column packed with NNAL specific MIP beads. The method was used for analysis of urinary NNAL and NNAL-Gluc in smokers. Chemometric methods were used with this data to develop a potential cancer-risk-assessment tool based on pattern recognition in the concentrations of these compounds in urine. In the last part, method comparison approaches for the online and the offline sample extraction techniques were investigated. A ‘fixed’ range acceptance criterion based on combined considerations of method precision and accuracy, and the FDA bioanalytical guidance limits on precision and accuracy was proposed. Data simulations studies to evaluate the probabilities of successful transfers using the proposed criteria were performed. Various experimental designs were evaluated and a design comprised of 3 runs with 3 replicates each with an acceptance range of ±20% was found appropriate. The off-line and the on-line sample extraction methods for NNAL analysis were found comparable using the proposed fixed range acceptance criteria.

L’objectif de cette thèse a consisté en la synthèse d’un polymère à empreinte moléculaire (MIP) permettant l’extraction du phosmet, un pesticide organophosphoré largement utilisé en oléiculture. La recherche du monomère fonctionnel (MF) disposant de la meilleure capacité à interagir de manière non-covalente avec le phosmet en présence du solvant porogène le plus approprié a été réalisée pour la toute première fois au moyen d’un capteur à acétylcholinestérase. Cette stratégie innovante a permis une meilleure compréhension des mécanismes cinétiques à l’œuvre lors de l’interaction MF-molécule cible. De par l’importance de son rôle dans la détermination de la structure d’un MIP, le choix d’un agent réticulant aux caractéristiques physico-chimiques adéquates a permis de sélectionner le meilleur MIP en s’appuyant sur l’étude des isothermes d’adsorption selon les modèles de Freundlich et Langmuir. La procédure d’extraction du phosmet selon la procédure MISPE (Molecularly Imprinted Solid Phase Extraction) a été effectuée par le biais d’une cartouche SPE dont la capacité a été évaluée à partir d’une solution standard. La validation du choix des réactifs de MIP sélectionnés a été confortée par la réalisation d’une expérience de réactivité croisée appliquée à une molécule analogue au phosmet. L’extraction du phosmet de l’huile d’olive a pu être effectuée avec succès selon un protocole d’extraction en flux inverse optimisé. Cette étude ouvre ainsi la voie à la recherche de nouvelles interactions MFs-molécules cibles au moyen de biocapteurs enzymatiques inhibant des composés toxiques tels que les herbicides, fongicides et autres pesticides. / The objective of this thesis has been the synthesis of a molecularly imprinted polymer (MIP) for the extraction of phosmet, an organophosphorus pesticide widely used in olive growing. The search for the functional monomer (FM) having the best ability to interact non-covalently with phosmet in the presence of the most suitable pore-forming solvent was carried out for the first time by means of an acetylcholinesterase sensor. This innovative strategy allowed us to better understand the kinetic mechanisms of FM-template interaction. Because of the importance of its role in determining the structure of a MIP, the selection of a crosslinking agent with adequate physicochemical characteristics made it possible to select the best MIP, whose adsorption isotherms were studied according to Freundlich and Langmuir models. Extraction of phosmet using a Molecularly Imprinted Solid Phase Extraction (MISPE) procedure was carried out via an SPE cartridge, whose capacity was evaluated from a standard solution. The choice of reagents and experimental conditions were validated by carrying out selectivity assays using another organophosphorus insecticide. Extraction of phosmet from olive oil was successfully carried out according to an optimized reverse flow extraction protocol. This work opens new opportunities for studying new FM-template interactions by means of enzymatic biosensors capable of detecting other inhibitors such as herbicides, fungicides and other pesticides.

O preparo da amostra é uma das etapas mais importantes em toda a análise química. O isolamento e a concentração dos componentes da amostra são cruciais e busca-se sempre que essas etapas sejam as mais simples e consumam o mínimo possível de tempo e reagentes. Nos últimos anos, um tipo de material tem se mostrado bastante útil para análises químicas a partir de fluidos biológicos, os polímeros molecularmente impressos (MIPs). Os MIPs são sintetizados por reações de polimerização, na presença de uma molécula molde (template). A molécula molde se liga aos monômeros funcionais do polímero durante a reação de polimerização e permanece ligada à superfície das cadeias poliméricas quando a reação se completa. Terminada a polimerização, realiza-se a completa lavagem das moléculas molde, assim, restam na superfície polimérica cavidades tridimensionais complementares à molécula empregada como molde. Essas cavidades permitem a ligação reversível e preferencial da molécula molde ou outras com estrutura química semelhante. A Cannabis sativa é a droga ilícita mais consumida em todo o mundo e nos últimos anos muita atenção tem se voltado a seus efeitos toxicológicos no corpo humano e a aplicações medicinais. Nesta dissertação, foi sintetizado um MIP com a molécula molde catequina para a extração e posterior análise por LC-MS/MS dos canabinóides &Delta;9-tetrahidrocanabinol (THC), 11-hidroxi-&Delta;9-tetrahidrocannabinol (THC-OH) e 11-nor-&Delta;9-tetrahidrocannabinol-9-ácido carboxílico (THC-COOH) em amostras de urina. O MIP produzido foi empacotado em microdispositivo e empregado no preparo das amostras de urina por microextração por sorvente empacotado (MEPS). O método desenvolvido apresentou boa linearidade (valores de r de 0,977 para o THC e 0,994 para THC-OH e THC-COOH). Os limites de detecção e de quantificação foram respectivamente de 5 ng mL-1 e 20 ng mL-1, para os compostos THC e THC-OH, na faixa linear de 25 a 250 ng mL-1. Para o composto THC-COOH os limites de detecção e quantificação alcançados foram de 1 ng mL-1 e 5 ng mL-1, respectivamente, na faixa linear de 5 a 170 ng mL-1. O método apresentou valores razoáveis de precisão entre 3,2% (THC-COOH) e 25,1% (THC) e de exatidão, que variou entre -18,4 e 17,4 (ambos para o THC). O MIP empregado no preparo da amostra mostrou-se mais seletivo e específico do que materiais normalmente empregados para a extração dos canabinoides das amostras de urina, além de a técnica de extração por MEPS apresentar baixo consumo de solventes e amostra para a extração dos analitos e posterior análise por LC-MS/MS. / The sample preparation is one of the most important steps in every chemical analysis. The isolation and concentration of the sample components are crucial and it is always sought that these steps are simple and consume the lowest amount of time and reagents. In the recent years, a type of material has proved to be very useful for chemical analyzes of biological fluids, the molecularly imprinted polymers (MIPs). MIPs are synthesized by polymerization reactions in the presence of a template molecule. The template molecule binds to the functional monomers of the polymer during the polymerization reaction and remains bonded to the surface of the polymeric chains after the reaction is complete. After the polymerization is finished, the complete washing of the template molecules is carried out, thus, three-dimensional cavities, complementary to the molecule used as a template, remain on the polymer surface. These cavities allow the reversible and preferential bonding of the template molecule or others with similar chemical structure. Cannabis sativa is the most commonly consumed illicit drug in the world and in recent years much attention has focused on its toxicological effects on human body and for medical applications. In this master dissertation, a MIP was synthesized with the catechin molecule as template, for extraction and subsequent analysis by LC-MS/MS of the cannabinoids &Delta;9-tetrahydrocannabinol (THC), 11-hydroxy-&Delta;9-tetrahydrocannabinol (THC-OH), and 11-nor-&Delta;9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in urine samples. The MIP produced was packed in a microdevice and used in the preparation of the urine samples by microextraction by packed sorbent (MEPS). The developed method showed good linearity (r values of 0.977 for THC and 0.994 for THC-OH and THC-COOH). The detection and quantification limits were respectively 5 ng mL-1 and 20 ng mL-1 for THC and THC-OH in the linear range from 25 to 250 ng mL-1. For the compound THC-COOH the limits of detection and quantification achieved were 1 ng mL-1 and 5 ng mL-1, respectively, in the linear range from 5 to 170 ng mL-1. The method presented reasonable values of precision, between 3.2% (for THC-COOH) and 25.1% (for THC) and displayed accuracy ranging from -18.4 to 17.4 (both for THC). The MIP used in the sample preparation was more selective and specific than other materials usually employed for the extraction of the cannabinoids from the urine samples. The MEPS technique also showed low consumption of solvents and sample for sample preparation, extraction of analytes and subsequent analysis by LC-MS/MS.

A venlafaxina (VEN), em razão de sua eficácia e brandos efeitos adversos, tem sido um dos antidepressivos mais prescritos no tratamento da depressão e ansiedade. Neste trabalho, um método analítico empregando as técnicas MISPE miniaturizada e cromatografia líquida acoplada à espectrometria de massas em Tandem, foi utilizado para a determinação de VEN e seus principais metabólitos em amostras de plasma para fins de monitorização terapêutica. A fase MIP foi sintetizada via polimerização radicalar por precipitação, fazendo uso de VEN (molécula molde), ácido metacrílico (monômero funcional), etileno glicol dimetacrilato, (reagente reticulante) e 2,2 azobisisobutironitrila (iniciador radicalar) em tolueno (solvente). Para controle utilizou-se o polímero não impresso (NIP), sintetizado por procedimento análogo ao do MIP, porém sem o uso da molécula molde. A caracterização química e estrutural dos polímeros foi realizada por espectroscopia no infravermelho com transformada de fourier e microscopia eletrônica de varredura. A otimização das variáveis de MISPE miniaturizada favoreceu a detectabilidade analítica e diminuiu o efeito de memória. As extrações realizadas com MIP apresentaram taxa de recuperação de 84% para VEN e de 2-28% para os antidepressivos (clorpromazina, fluoxetina, clomipramina, imipramina e sertralina). O polímero não impresso apresentou baixa recuperação para a VEN (taxa de recuperação: 49%) e para os demais antidepressivos (taxas de recuperação menores que 40%). Estes experimentos comprovam a seletividade da fase MIP desenvolvida. O método padronizado apresentou linearidade na faixa de 3 a 700 ng mL-1 para VEN, 5 a 700 ng mL-1 para O-desmetilvenlafaxina (ODV) e de 3 a 500 ng mL-1 para N-desmetilvenlafaxina (NDV), precisão com coeficientes de variação menores que 15% e exatidão com valores de erro padrão relativo na faixa de -11,8 a 16,01 %. As concentrações correspondentes aos limites inferiores de quantificação para VEN (3 ng mL-1) e ODV ( 5 ng mL-1) foram inferiores aos intervalos terapêuticos preconizados. O método desenvolvido, quando comparado a aos métodos da literatura para determinação de VEN e metabolitos, apresentou maior seletividade, menor consumo de amostra e de solventes orgânicos e permitiu a reutilização da fase extratora. Segundo os parâmetros de validação analítica avaliados e amostras de pacientes em terapia com VEN analisadas, o método proposto é adequado para determinação de VEN, ODV e NDV em amostras de plasma para fins de monitorização terapêutica. / Venlafaxine elicits a small number of adverse effects, so it is one of the most frequently prescribed drugs to treat major depression, generalized anxiety, and social anxiety disorders in adults. In this study, venlafaxine (VEN), O-desmethylvenlafaxine (ODV), and N-desmethylvenlafaxine (NDV) were pre-concentrated with the aid of miniaturized SPE based on MIPs as extraction phase. MIPs are synthetic polymers with cavities specifically designed to hold a target molecule or structurally similar compounds. The molecularly imprinted polymers were prepared by addition of VEN, metacrylic acid (MAA, monomer), ethylene glycol dimethacrylate (EGDMA, cross-linker), and 2,2-azobisisobutyronitrile (AIBN, initiator) to toluene (solvent). The non-imprinted polymer (NIP), used for comparison, was also synthesized by following exactly the same procedure, but excluding the template VEN from the formulation. The polymer was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy (SEM). Optimization of the MIP phase extraction variables favored miniaturized analytical detectability and reduced the memory effect. The extractions performed with the synthesized MIP showed recovery rate of 84% for VEN and 2-28% for other antidepressants (chlorpromazine, fluoxetine, clomipramine, imipramine, and sertraline). The non-imprinted polymer provided low recovery of VEN (recovery rate: 49%) and other antidepressants (recovery rates lower than 40%). These experiments demonstrated the selectivity of the developed MIP phase. The standardized method was linear in the range of 300 - 700 ng mL-1 for VEN, 5-700 ng mL-1 for ODV, and 3 to 500 ng mL-1 for NDV. Precision had coefficients of variation smaller than 15%; the accuracy standard error values ranged from -11.8 to 16.01%. Compared with literature methods, the developed method was more selective for determination of VEN and metabolites, required lower consumption of sample and organic solvents, and enabled reuse of the extraction phase. According to the assessed analytical validation parameters and to the analysis of samples obtained from patients undergoing therapy with VEN, the proposed method is suitable to determine VEN, NDV, and ODV in plasma samples for therapeutic drug monitoring.

Au cours des dernières décennies, les capteurs et les biocapteurs électrochimiques ont connu un développement considérable en raison de leur simplicité, fiabilité, rapidité et sélectivité. Ils ont constitué les alternatives les plus séduisantes pour les méthodes analytiques classiques dans des domaines aussi variés que l'agro-alimentaire, la médecine et la biologie clinique, ou le contrôle de la qualité de l'environnement. Dans ce travail de recherche, nous nous sommes intéressés, dans un premier volet, aux développements des immunocapteurs et capteurs électrochimiques à base des polymères à empreintes moléculaires (MIPs) pour le contrôle de la qualité des miels. La première partie de ce volet concerne le développement des immunocapteurs sur des structures dites Bio-MEMS basées sur des microélectrodes en or. L'élaboration de ces immunocapteurs a été dédiée à la détection des résidus d'antibiotiques à savoir la sulfapyridine (SPy) et la tétracycline (TC). Une nouvelle structure des nanoparticules magnétiques (MNPs) revêtues du copolymère poly (acide pyrrole-co-pyrrole-2-carboxylique) a été exploitée dans ces travaux pour leur réseau d'immobilisation tridimensionnel ainsi que pour leur stabilité pendant de longues périodes. La détection de la SPy et de la TC a été réalisée par différentes approches compétitives en utilisant des anticorps polyclonaux. Dans la deuxième partie de ce volet, nous avons fabriqué des capteurs à base des MIPs pour la détection de la sulfaguanidine, la doxycycline et le chloramphénicol dans le miel. Ces dispositifs ont été développés sur la surface des électrodes sérigraphiées en or en employant une matrice polymérique du polyacrylamide en présence des molécules empreintes. Les performances de ces capteurs et biocapteurs (limite de détection, sélectivité, reproductibilité, application dans les milieux réels) ont ensuite été évaluées. Dans un deuxième volet, nous nous sommes parvenus à appliquer un dispositif de la langue électronique voltammétrique (Langue-EV) pour des analyses agroalimentaires et biomédicales. Dans un premier temps, nous avons discriminé les miels issus de quatorze régions de la France et du Maroc par le dispositif de la Langue-EV. Nous nous sommes aussi parvenus à démontrer la fiabilité de ce dispositif à prédire les résultats des différents paramètres physico-chimiques d'après les réponses des méthodes analytiques utilisées. Dans un deuxième temps, nous sommes passés à l'application du dispositif de la Langue-EV en analyse biomédicale dans le but de discriminer les urines des patientes souffrants des infections urinaires avec celles des femmes saines / In recent decades, the use of electrochemical sensors and biosensors have grown considerably due to their simplicity, reliability, rapidity, and selectivity. They were the most attractive alternative tools for conventional analytical methods in various fields such as food control, medicine, and clinical biology or environmental control. In this research works, we focused, in the first part, on the development of immunosensors and electrochemical sensors based on molecularly imprinted polymers (MIPs) for the quality control of honey. In the second part, we managed to apply a voltammetric electronic tongue (VE-tongue) for food monitoring and biomedical analyzes. The first part of our research work concerns the development of immunosensors based on gold microelectrodes of the Bio-MEMS devices. The development of these immunosensors was dedicated to the detection of antibiotic residues namely sulfapyridine (SPy) and tetracycline (TC). A new structure of magnetic nanoparticles (MNPs) coated with the poly (pyrrole-co-pyrrole-2-carboxylic acid) copolymer has been exploited in this work for their three-dimensional immobilization network as well as for their stability for long periods. The detection of SPy and TC was performed by different competitive approaches using polyclonal antibodies. In this part, we have also synthesized the MIP sensors dedicated to the detection of sulfaguanidine, doxycycline, and chloramphenicol in honey. These devices have been developed on the surface of the screen-printed gold electrodes by employing a polyacrylamide matrix in the presence of the target molecules. The performances of these sensors and biosensors (limit of detection, selectivity, reproducibility, applications in real samples) were then evaluated. Regarding the second part of our research works, it involved the discrimination between honeys from fourteen regions from France and Morocco. We have succeeded in demonstrating the reliability of this device in predicting the results of the different physico-chemical parameters of honey samples according to the responses of the used analytical methods. In other steps, we proceeded to the application of the VE-tongue in biomedical analyzes to discriminate urine specimens of patients suffering from urinary tract infections and those of healthy subjects

O preparo da amostra é uma das etapas mais importantes em toda a análise química. O isolamento e a concentração dos componentes da amostra são cruciais e busca-se sempre que essas etapas sejam as mais simples e consumam o mínimo possível de tempo e reagentes. Nos últimos anos, um tipo de material tem se mostrado bastante útil para análises químicas a partir de fluidos biológicos, os polímeros molecularmente impressos (MIPs). Os MIPs são sintetizados por reações de polimerização, na presença de uma molécula molde (template). A molécula molde se liga aos monômeros funcionais do polímero durante a reação de polimerização e permanece ligada à superfície das cadeias poliméricas quando a reação se completa. Terminada a polimerização, realiza-se a completa lavagem das moléculas molde, assim, restam na superfície polimérica cavidades tridimensionais complementares à molécula empregada como molde. Essas cavidades permitem a ligação reversível e preferencial da molécula molde ou outras com estrutura química semelhante. A Cannabis sativa é a droga ilícita mais consumida em todo o mundo e nos últimos anos muita atenção tem se voltado a seus efeitos toxicológicos no corpo humano e a aplicações medicinais. Nesta dissertação, foi sintetizado um MIP com a molécula molde catequina para a extração e posterior análise por LC-MS/MS dos canabinóides &Delta;9-tetrahidrocanabinol (THC), 11-hidroxi-&Delta;9-tetrahidrocannabinol (THC-OH) e 11-nor-&Delta;9-tetrahidrocannabinol-9-ácido carboxílico (THC-COOH) em amostras de urina. O MIP produzido foi empacotado em microdispositivo e empregado no preparo das amostras de urina por microextração por sorvente empacotado (MEPS). O método desenvolvido apresentou boa linearidade (valores de r de 0,977 para o THC e 0,994 para THC-OH e THC-COOH). Os limites de detecção e de quantificação foram respectivamente de 5 ng mL-1 e 20 ng mL-1, para os compostos THC e THC-OH, na faixa linear de 25 a 250 ng mL-1. Para o composto THC-COOH os limites de detecção e quantificação alcançados foram de 1 ng mL-1 e 5 ng mL-1, respectivamente, na faixa linear de 5 a 170 ng mL-1. O método apresentou valores razoáveis de precisão entre 3,2% (THC-COOH) e 25,1% (THC) e de exatidão, que variou entre -18,4 e 17,4 (ambos para o THC). O MIP empregado no preparo da amostra mostrou-se mais seletivo e específico do que materiais normalmente empregados para a extração dos canabinoides das amostras de urina, além de a técnica de extração por MEPS apresentar baixo consumo de solventes e amostra para a extração dos analitos e posterior análise por LC-MS/MS. / The sample preparation is one of the most important steps in every chemical analysis. The isolation and concentration of the sample components are crucial and it is always sought that these steps are simple and consume the lowest amount of time and reagents. In the recent years, a type of material has proved to be very useful for chemical analyzes of biological fluids, the molecularly imprinted polymers (MIPs). MIPs are synthesized by polymerization reactions in the presence of a template molecule. The template molecule binds to the functional monomers of the polymer during the polymerization reaction and remains bonded to the surface of the polymeric chains after the reaction is complete. After the polymerization is finished, the complete washing of the template molecules is carried out, thus, three-dimensional cavities, complementary to the molecule used as a template, remain on the polymer surface. These cavities allow the reversible and preferential bonding of the template molecule or others with similar chemical structure. Cannabis sativa is the most commonly consumed illicit drug in the world and in recent years much attention has focused on its toxicological effects on human body and for medical applications. In this master dissertation, a MIP was synthesized with the catechin molecule as template, for extraction and subsequent analysis by LC-MS/MS of the cannabinoids &Delta;9-tetrahydrocannabinol (THC), 11-hydroxy-&Delta;9-tetrahydrocannabinol (THC-OH), and 11-nor-&Delta;9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in urine samples. The MIP produced was packed in a microdevice and used in the preparation of the urine samples by microextraction by packed sorbent (MEPS). The developed method showed good linearity (r values of 0.977 for THC and 0.994 for THC-OH and THC-COOH). The detection and quantification limits were respectively 5 ng mL-1 and 20 ng mL-1 for THC and THC-OH in the linear range from 25 to 250 ng mL-1. For the compound THC-COOH the limits of detection and quantification achieved were 1 ng mL-1 and 5 ng mL-1, respectively, in the linear range from 5 to 170 ng mL-1. The method presented reasonable values of precision, between 3.2% (for THC-COOH) and 25.1% (for THC) and displayed accuracy ranging from -18.4 to 17.4 (both for THC). The MIP used in the sample preparation was more selective and specific than other materials usually employed for the extraction of the cannabinoids from the urine samples. The MEPS technique also showed low consumption of solvents and sample for sample preparation, extraction of analytes and subsequent analysis by LC-MS/MS.