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 Δ9-tetrahidrocanabinol (THC), 11-hidroxi-Δ9-tetrahidrocannabinol (THC-OH) e 11-nor-Δ9-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 Δ9-tetrahydrocannabinol (THC), 11-hydroxy-Δ9-tetrahydrocannabinol (THC-OH), and 11-nor-Δ9-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.

La stéréolithographie biphotonique (TPS) est une technique de microfabrication 3D basée sur la polymérisation par absorption biphotonique qui permet d’obtenir en une seule étape des structures 3D complexes avec des détails sub-100nm. Aujourd’hui, en raison des conditions spécifiques de fabrication liées à la TPS (fort flux, confinement spatial de la photoréaction,…), un des enjeux concerne le développement de matériaux fonctionnels compatibles avec ce procédé. Dans ce contexte, l’objectif de cette thèse a été de développer de nouveaux matériaux fonctionnels à base de polymères à empreintes moléculaires (MIP) pour élaborer des capteurs chimiques. Une première partie de ce travail a consisté à mettre en place différentes méthodes dédiées à la caractérisation des propriétés géométriques, chimiques et mécaniques des matériaux élaborés par TPS. Par exemple, la vibrométrie laser a été utilisée pour la première fois afin de sonder de façon non-invasive les propriétés mécaniques de microstructures réalisées par TPS. Dans un second temps, ce travail a été mis à profit pour étudier l’impact du processus de fabrication (i.e. conditions photoniques) ainsi que des paramètres physico-chimiques affectant la photoréaction (i.e. inhibition par oxygène et nature du monomère) sur les propriétés finales des matériaux. Enfin, en s’appuyant sur les résultats obtenus, des microcapteurs chimiques à base de MIP, à lecture optique ou mécanique, ont été fabriqués. Leurs propriétés de reconnaissance moléculaire, ainsi que leurs sélectivités ont été démontrées pour une molécule cible modèle (D-L-Phe). / The two-photon stereolithography (TPS) technique is a micro-nanofabrication method based on photopolymerization by two-photon absorption that allows in a single manufacturing step to obtain complex 3D structures with high-resolution details (sub-100nm). Due to the specific conditions of TPS process (intense photon flux, spatial confinement of the photoreaction…) one of the main concerns today is the development of functional materials compatible with the TPS. According to the aforementioned, the general objective of this thesis was to develop new functional materials based on molecularly imprinted polymers (MIP) to elaborate chemical microsensors. In the first step of this work, different methods were implemented to characterize the geometrical, chemical and mechanical properties of the materials synthesized by TPS. For example, laser-Doppler vibrometry was used for first time to evaluate the mechanical properties of microstructures fabricated by TPS in a non-invasive way. In the second step, the characterization methodology was used to study the impact of the manufacturing process (i.e. photonic conditions) and the physicochemical parameters that affect the photoreaction (i.e. oxygen inhibition and the nature of the monomer) and the final properties of the materials. Finally, the obtained results enabled the prototyping of chemical microsensors based on MIP. Their molecular recognition properties and their selectivity were demonstrated for the molecule (D-L-Phe) by an optical and a mechanical sensing method.

<p>The thesis describes the synthesis of chromatographic media using several different approaches, their characterizations and applications in liquid chromatography. The steps to achieve a separation column for a specific analyte are presented. The main focus of the study was the design of novel molecularly imprinted polymers.</p><p>Attachment of monolithic polymeric substrates to the walls of fused silica capillaries was studied in Paper I. With a broad literature survey, a set of common methods were tested by four techniques and ranked by their ability to improve anchoring of polymers. The best procedure was thus used for all further studies.</p><p>Synthesis of monoliths in capillary columns was studied in Paper II. With the goal of separating proteins without denaturation, various monoliths were polymerized in situ using a set of common monomers and cross-linkers mixed with poly(ethylene glycol) as porogen. The resulting network was expected to present “protein-friendly pores”. Chemometrics were used to find and describe a set of co-porogens added to the polymerization cocktails in order to get good porosity and flow-through properties.</p><p>Assessment of the macroporous structure of a monolith was described in Paper III. An alternative method to mercury intrusion porosimetry was proposed. The capillaries were embedded in a stained resin and observed under transmission electron microscope. Images were then computed to determine the pore sizes.</p><p>Synthesis of molecularly imprinted polymers grafted to a core mono-lith in a capillary was described in Paper IV. The resulting material, imprinted with local anaesthetics, was tested for its chromatographic performance. Similar imprinted polymers were characterized by microcalorimetry in Paper V. Finally, imprinted monoliths were also synthesized in a glass tube and further introduced in a NMR rotor to describe the interactions between stationary phase and template in Paper VI.</p>

The thesis describes the synthesis of chromatographic media using several different approaches, their characterizations and applications in liquid chromatography. The steps to achieve a separation column for a specific analyte are presented. The main focus of the study was the design of novel molecularly imprinted polymers. Attachment of monolithic polymeric substrates to the walls of fused silica capillaries was studied in Paper I. With a broad literature survey, a set of common methods were tested by four techniques and ranked by their ability to improve anchoring of polymers. The best procedure was thus used for all further studies. Synthesis of monoliths in capillary columns was studied in Paper II. With the goal of separating proteins without denaturation, various monoliths were polymerized in situ using a set of common monomers and cross-linkers mixed with poly(ethylene glycol) as porogen. The resulting network was expected to present “protein-friendly pores”. Chemometrics were used to find and describe a set of co-porogens added to the polymerization cocktails in order to get good porosity and flow-through properties. Assessment of the macroporous structure of a monolith was described in Paper III. An alternative method to mercury intrusion porosimetry was proposed. The capillaries were embedded in a stained resin and observed under transmission electron microscope. Images were then computed to determine the pore sizes. Synthesis of molecularly imprinted polymers grafted to a core mono-lith in a capillary was described in Paper IV. The resulting material, imprinted with local anaesthetics, was tested for its chromatographic performance. Similar imprinted polymers were characterized by microcalorimetry in Paper V. Finally, imprinted monoliths were also synthesized in a glass tube and further introduced in a NMR rotor to describe the interactions between stationary phase and template in Paper VI.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2018-08-20T13:36:48Z No. of bitstreams: 2 Dissertação - Lidya Cardozo da Silva - 2018.pdf: 2382834 bytes, checksum: e5a79619d923d442540c5bf0549318bd (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-08-20T13:38:04Z (GMT) No. of bitstreams: 2 Dissertação - Lidya Cardozo da Silva - 2018.pdf: 2382834 bytes, checksum: e5a79619d923d442540c5bf0549318bd (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-08-20T13:38:04Z (GMT). No. of bitstreams: 2 Dissertação - Lidya Cardozo da Silva - 2018.pdf: 2382834 bytes, checksum: e5a79619d923d442540c5bf0549318bd (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-07-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Jatropha curcas L. is a euphorbiaceous oilseed plant considered toxic to humans and animals due to the presence of phorbol esters (PEs). Traditionally, the detection of these toxic compounds has been done in J. curcas seeds and derivates via chromatographic separation methods such as HPLC-UV and HPLC-MS. Although efficient, these techniques are laborious and require high time and solvent consumption, thus it would be interesting the development of new analytical methods to determine these compounds with more practicality. Probe electrospray ionization is frequently used in ambient mass spectrometry allowing analysis with minimum sample preparation. However, for complex samples analysis, this technique presents low sensitivity and ionization suppression. In this study, a molecularly imprinted polymer-coated probe electrospray ionization mass spectrometry (MIPCPESI-MS) method was developed for determination of phorbol esters in methanolic extracts of Jatropha curcas leaves with direct extraction form the ionization source. The synthesized molecularly imprinted polymer (MIP) proved to be adequate for extraction of the PEs in methanolic extracts of J. curcas leaves with better performance as extraction phase in comparison with the non-imprinted polymer (NIP). The MIPCPESI method allowed detection of phorbol 12,13-diacetate (PDA) and other three PEs metabolite ions from Jatropha leaves with minimal sample preparation, and with higher signal intensities compared to analysis with conventional PESI. For the PDA, calibration curve exhibited linearity with R2 > 0.99, LOD and LOQ in µg.mL-1 range, precision and accuracy values, respectively, between 4.06 to 13.49% and -1.60 to -15.26 %. Finally, MIPCPESI was employed for PDA quantification in methanolic extracts of six different J. curcas leaves genotypes resulting in concentrations ranging from 222.19 ± 23.55 to 528.23 ± 19.72 µg.g-1 for toxic samples. / A Jatropha curcas L. é uma oleaginosa euforbiácea considerada tóxica para humanos e animais devido à presença de ésteres de forbol (PEs). Tradicionalmente, a detecção destes compostos tóxicos tem sido feita em tortas e sementes de J. curcas por meio do uso de técnicas de separação cromatográfica como HPLC-UV e HPLC-MS que apesar de eficientes são laboriosas e requerem alto consumo de tempo e solventes. Dessa forma, seria interessante o desenvolvimento de novas técnicas analíticas para determinação desses compostos com maior praticidade. Probe electrosrpay ionization (PESI) é uma das técnicas de ionização utilizadas na espectrometria de massas ambiente que permite análises rápidas com mínimo preparo de amostras. No entanto, para análise de amostras complexas essa técnica apresenta baixa sensibilidade e supressão iônica. Neste estudo, foi desenvolvido um método de análise por espectrometria de massas por Probe electrospray revestido com polímero molecularmente impresso (MIPCPESI-MS) para determinação de ésteres de forbol em extratos metanólicos de folhas de Jatropha curcas com extração direta da fonte de ionização. O polímero molecularmente impresso (MIP) sintetizado mostrou-se adequado para extração de PEs em extratos metanólicos de folhas de J. curcas tendo melhor desempenho como fase extratora quando comparado ao polímero não molecularmente impresso (NIP). O método MIPCPESI-MS possibilitou a detecção do forbol 12,13-diacetato (PDA) e de outros três íons metabólitos presentes nas folhas de J. curcas com mínimo preparo de amostras e com maior intensidade de sinais quando comparado às análises com PESI convencional. Para o PDA, a curva de calibração apresentou linearidade com R2 > 0.99, LOD e LOQ na faixa de µg.mL-1, valores de precisão entre 4.06 e 13.49 % e exatidão entre -1.60 e -15.26 %. Posteriormente, o método MIPCPESI foi empregado na quantificação de PDA em seis extratos metanólicos de diferentes genótipos de folhas de J. curcas resultando em valores concentrações entre 222.19 ± 23.55 a 528.23 ± 19.72 µg.g-1 nas amostras tóxicas.

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.

Les capteurs électrochimiques sont des outils pour la détection fiable, peu coûteux, avec une haute sensibilité et sélectivité, pour la détermination des composés biologiques et chimiques dans les domaines du diagnostic clinique, l'environnement et l'industrie alimentaire. Particulièrement, les Immunocapteurs, alliant une très grande spécificité. Également des nouveaux techniques produisent des résultats similaires, par exemple, les capteurs basés sur la technique des Polymères à empreinte moléculaire, la quelle produise des récepteurs artificiels. La technique devient très important dans les sciences bioanalytiques parce qu'il porte des avantages inhérents sur les récepteurs naturels: une grande stabilité dans des diffèrent environnement et conditions, également comptent avec une grande flexibilité dans la conception, une large gamme de molécules peuvent être utilisées. L'objectif du travail présenté ici est de développer des capteurs électrochimiques avec une très grande affinité et spécificité pour une analyte. Les quelles comprennent des applications très divers comme dans la protection de l'environnement, la sécurité alimentaire et le domaine biomédical. La première partie de la thèse présent l'état actuel de la conception et techniques de fabrication des biocapteurs. Ensuite, les aspects généraux des immuno capteurs électrochimiques et capteurs base sur des aptamères sont présentés ici, ainsi que plusieurs exemples rapportés dans la littérature pour la détection de marqueurs biologiques du cancer. Les avantages de l'intégration nanomatériaux dans les dispositifs de détection sont présentés. Ensuite, plusieurs aspects sur la technique des Polymères à empreinte moléculaire sont introduits. La partie personnelle de contribution est structuré en trois chapitres: en premier temps la méthodologie et les résultats obtenus pour le développement de deux essais biologiques pour la détection du marqueur tumoral Mucinl. Le premier chapitre est dédié sur un capteur à base de billes magnétiques, dans le deuxième chapitre une capteur aptamère base sur des nanoparticules d'or sans aucun marquage et finalement un capteur basée sur la technique des Polymères à empreinte moléculaire, cette protocole a été appliqué pour la détection d'explosifs, des médicaments, des hormones et les pesticides / Electrochemical sensors provide reliable and inexpensive tools for the determination of biological and chemical compounds with high sensitivity and selectivity, in the fields of clinical diagnosis, environment protection and food industry. Immunosensors hold particular promise, combining the high specificity of immuno- reactions with the sensitivity of electrochemical methods. Artificial receptors based on molecularly imprinted technique attracted considerable attention in bioanalytical sciences due to inherent advantages over natural receptors, such as high stability in harsh conditions and freedom of molecular design towards a wide range of molecules. The aim of the thesis presented here was to develop electrochemical affinity sensors based on various recognition receptors for environment monitoring, food safety and biomedical field. The first part of the thesis reviews the current state of knowledge in these fields. General aspects of electrochemical immuno- and apta-sensors are presented herein, together with several examples reported in the literature for the detection of cancer biomarkers. The advantages of integrating nanomaterials in sensing devices are then presented. At last, several aspects of the molecularly imprinted polymers are introduced. The personal contribution part is structured in three chapters, that include the methodology and results obtained for the development of biosensors for the detection of Mucinl tumor marker, the first chapter being focused on bioassays based on magnetic beads and second chapter on a label-free aptasensor based on gold nanoparticles, and finally, a third chapter dedicated to the molecularly imprinted-based sensors for the detection of explosives, drugs, hormones and pesticides

Au cours des dernières années, les matériaux énergétiques, tels que le 2,4,6-trinitrotoluène (TNT) et le 1,3,5-trinitro perhydro-1,3,5-triazine (RDX), ont été utilisés lors des activités d’entrainement militaire, ayant un impact potentiel sur l’environnement, les bases militaires, la population environnante, la faune et la flore. Sur les champs de tir, les sols à proximité des cibles et autour des positions de tir nécessitent une surveillance particulière, puisqu’il est possible de trouver une importante quantité de résidus d’explosif qui peuvent être transportés vers les eaux de surface et des eaux souterraines avec les précipitations. Toutefois, la procédure actuelle pour détecter des matériaux énergétiques dans l'eau naturelle est complexe, longue, nécessite un personnel hautement spécialisé et augmente le risque de contamination croisée. Par conséquent, il est difficile d'assurer un contrôle rapide et continu des contaminants. En fait, l'objectif des travaux présentés dans ce mémoire est de développer une technique pour identifier et quantifier les explosifs et leurs produits de dégradation dans les eaux naturelles. En outre, ce test doit être in situ, en continu, peu coûteux et rapide. La résonance des plasmons de surface (SPR) a été donc utilisée pour quantifier les matériaux énergétiques. Une matrice de bis-aniline réticulée avec des nanoparticules d’or (AuNPs) est utilisée en tant que polymère à empreinte moléculaire (MIP) sur le film d'or pour capturer sélectivement le composé d’intérêt. L'association de la molécule d’intérêt, tel que le TNT ou RDX, au MIP par interactions π-donneur-accepteur permet la détection d'explosifs suite aux changements d’indice de réfraction sur la sonde. Le couplage entre les plasmons des AuNPs et de la couche d'or peut également augmenter les signaux SPR. Le test optimisé a ensuite été utilisé sur une base militaire canadienne. L'utilisation de cet essai à base de MIP fournit un outil pour l'extraction et la pré-concentration de TNT ou RDX à la surface d’une sonde SPR et permet leur détection en continu de faibles concentrations dans les eaux naturelles. / Over the last few years, energetic materials such as 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) have been used and show a probable environmental impact on military bases, the surrounding population, fauna and flora, caused by military training involving munitions. On shooting ranges, soils near the firing positions and around targets require special monitoring, since the quantities of explosives residues found can be significant, and these compounds can be transported to surface water and groundwater by precipitation. However, the current procedure to detect energetic materials in natural water is complex, long and poorly adapted to. These operations require highly specialized personnel and increase the risk of cross contamination. Therefore, it is difficult to ensure a fast and continuous monitoring of the contaminants. Here, the objective is to develop a technique for identifying and quantifying explosives and their degradation products in natural water. Also, this test has to be in-situ, inexpensive and fast. Surface plasmon resonance (SPR) has been proposed to probe energetic materials. A bis-aniline-cross-linked gold nanoparticles (AuNPs) matrix is used as a molecular imprinted polymer (MIP) on gold film to selectively capture the target compound. The association of the target such as TNT or RDX to the MIP with π-donor-acceptor interactions have allow the detection of explosives by following SPR refractive changes. Plasmon coupling effects between the AuNPs and the gold film could also increase the SPR signals. The optimal sensor was then used on site to detect RDX in underground water of a Canadian military base. The utilisation of MIP based assay will provide a tool for the extraction and pre-concentration of TNT or RDX on the detector’s surface and will allow the detection of lower concentrations in natural water.

Cette thèse décrit l'état de l'art des sondes et nanoparticules fluorescents traditionnels utilisés en imagerie de fluorescence ainsi que le développement de nouveaux nanomatériaux à base de polymère à empreinte moléculaire, aussi dénommé ‘anticorps plastique’, pour le ciblage et la bioimagerie. En biologie et en médecine, il y a un besoin constant de diagnostiquer diverses maladies pour leur éventuel traitement et prévention. Une distribution anormale et un taux élévé de glycosylation (e.g. acides hyaluronique et sialique) à la surface ou dans les cellules sont indicateurs d’une infection ou d’un cancer. Généralement, l’imagerie par fluorescence permet de visualiser, localiser et quantifier les biomarqueurs de pathologie mais à l’heure actuelle, il n’existe pas d’outil analytique fiable pour cibler spécifiquement les molécules de glycosylation car les anticorps et les lectines vendus dans le commerce ont une faible affinité et sélectivité vis-à-vis de ces cibles. Dans ce contexte, les polymères à empreintes moléculaires (MIPs) pourraient apporter une solution. Les MIPs sont des récepteurs synthétiques possédant des affinités et sélectivités comparables à ceux des anticorps, mais exhibant une stabilité physique, thermique et chimique bien plus accrue. De plus, leur fabrication est peu coûteuse et ne nécessite pas de tuer des animaux comme pour l’obtention des anticorps biologiques. Dans cette thèse, nous avons optimisé et synthétisé des MIPs biocompatibles pour leur utilisation en bioimagerie afin de détecter et quantifier l’acide hyaluronique et l’acide sialique sur les cellules et les tissus de peau humaine. L’acide glucuronique, une composante de l’acide hyaluronique et l’acide N-acétylneuraminique, l’acide sialique le plus commun, ont été utilisés comme molécules ‘patron’, générant des MIPs très sélectifs envers leur cible en milieu aqueux. Deux types de nanoparticules de MIPs fluorescents ont été synthétisés: (1) en incorporant un colorant rhodamine polymérisable dans la solution de pré-polymérisation et (2) en encapsulant des boîtes quantiques InP/ZnS générant ainsi des MIPs de type cœur-coquille. Pour cela, nous avons adopté une stratégie innovante qui consiste à synthétiser les coquilles de MIPs directement autour des boîtes quantiques en utilisant l’énergie de l’onde fluorescente émise par l’excitation des points quantiques, pour initier la polymérisation. Un protocole d'immunocoloration standard a ensuite été optimisé afin d’imager des kératinocytes humains fixés et vivants ainsi que des tissus de peau, par microscopie à épifluorescence et confocale. Les résultats étaient similaires à ceux obtenus par la méthode de référence utilisant une protéine biotinylée reconnaissant l'acide hyaluronique. L'imagerie multiplex en combinant deux MIPs couplés à deux couleurs de boîtes quantiques et l’imagerie des cellules cancéreuses ont également été démontrées. Bien que les MIPs n’étaient pas cytotoxiques aux concentrations utilisées pour la bioimagerie, la toxicité des différentes composantes du MIP pourrait être un frein à leur utilisation dans le domaine biomédical. Afin de rendre ces MIPs plus ‘inoffensifs’, nous avons supprimé l’amorceur de polymérisation, une molécule considérée comme toxique. Les MIPs ont été synthétisés en employant des monomères qui s’auto-initient sous l’effet de l’UV ou de la chaleur. La spécificité et la sélectivité des MIPs obtenus étaient similaires à ceux préparés avec des amorceurs. En conclusion, cette thèse décrit la première utilisation des MIPs comme anticorps synthétique pour la bioimagerie de fluorescence. Ce travail ouvre la voie à de nouvelles applications en détection, diagnostique et thérapie par des MIPs. / This thesis describes the state of the art in nanomaterials-based targeted bioimaging and introduces molecularly imprinted polymers, also termed ‘plastic antibodies’ as novel biorecognition agents for labeling and imaging of cells and tissues. In fundamental biology and medical diagnostics, there is a constant need to localize and quantify specific molecular targets. Abnormal glycosylation levels or distributions of hyaluronan or sialic acids on cells are indicators of infection or malignancy. In general, bioimaging with fluorescent probes enables the localization and qualitative or quantitative determination of these pathological biomarkers. However, no reliable tools for the recognition of glycosylation sites on proteins exist, because the commercially available antibodies or lectins have poor affinity and selectivity for these targets. In this context, tailor-made molecularly imprinted polymers (MIPs) are promising synthetic receptor materials since they present a series of advantages over their natural counterparts such as the ease and low cost of preparation and their physical and chemical stability. Thus, MIPs could provide a robust and specific imaging tool for revealing the location/distribution, time of appearance and structure of glycosylation sites on/in cells, which would lead to a better insight of the tremendously diverse biological processes in which these molecules are involved. Herein, we describe the synthesis of water-compatible MIPs for the molecular imaging of hyaluronan and sialylation sites on cells and tissues. Since molecular imprinting of entire biomacromolecules like oligosaccharides is challenging, we opted for what is commonly called the ‘epitope approach’, which was inspired by nature. The monosaccharides, glucuronic acid and N-acetylneuraminic acid were imprinted, and the resulting MIPs were able to bind these molecules when present and accessible on the terminal unit of hyaluronan and sialylation sites. Fluorescent MIPs were synthesized as rhodamine-labeled nanoparticles and as MIP-coated InP/ZnS core-shell quantum dot (QD) particles. For the coating of the QDs, a novel versatile solubilization and functionalization strategy was proposed, which consists of creating polymer shells directly on QDs by photopolymerization using the particles as individual internal light sources. A standard immunostaining protocol was then successfully adapted for the application of the fluorescently labeled MIPs to image fixed and living human keratinocytes and skin tissues, by epifluorescence and confocal fluorescence microscopy. The results were comparable to those obtained with a reference method where staining was done with a biotinylated hyaluronic acid binding protein. Multiplexed and cancer cell imaging were also performed, demonstrating the potential of molecularly imprinted polymers as a versatile biolabeling and bioimaging tool. Although the MIPs were not cytotoxic at the concentrations used for bioimaging, in order to render them generally applicable in biomedicine, where toxicity of the polymerization precursors is a matter of concern, we suppressed the initiator, a toxic chemical. Initiator-free MIPs were thus synthesized by using monomers that can self-initiate under UV irradiation or heat. The specificity and selectivity of the obtained MIPs were as good as the ones prepared with initiators. In conclusion, we have demonstrated for the first time the great potential of MIPs as synthetic antibody mimics for bioimaging. The possibility to associate other functionalities such as QDs and additionally attach drugs to the same material appears rather straightforward due to the synthetic polymeric nature of MIPs, which paves the way to new potential applications in theranostics.