Vários estudos que tentam compreender a gênese da aterosclerose têm demonstrado evidências que a oxLDL é peça importante para o desenvolvimento da doença, tornando-a um importante marcador. Os objetivos deste trabalho foram propor um novo imunossensor empregando anticorpos monoclonais anti-oxLDL e desenvolver um processo inovador de obtenção de anticorpos plásticos anti-oxLDL. Para construção do imunossensor, a região Fc do anticorpo foi ligada ao eletrodo de trabalho do dispositivo AuSPE (Screen-Printed Gold Electrodes), utilizando cisteamina. Posteriormente, foi adicionado BSA como bloqueador de possíveis regiões livres. Após o bloqueio, o imunossensor foi testado com oxLDL e outros antígenos, como forma de garantir a especificidade. Em relação aos anticorpos plásticos, chamados MAPS, estes foram desenvolvidos contruindo uma camada impressa de forma invertida ao anticorpo plástico SPAN, referência deste trabalho. Após obtenção dos MAPSs, estes passaram por diversos testes, similar ao imunossensor. Os resultados demonstraram excelente sensibilidade e especificidade às moléculas de oxLDL com detecção em tempo real em ambas as metodologias. / Increased levels of plasma oxLDL are associated with atherosclerosis, and the subsequent development of severe cardiovascular diseases that are today a major cause of death in modern countries. It is therefore important to find a reliable and fast assay to determine oxLDL. A new Immunosensor employing three monoclonal antibodies against oxLDL and a backside protein-surface imprinting process are proposed in this work. To generate the Immunosensor the mAbs were set-up by cysteamine on a gold layer of a disposable screen-printed electrode. BSA was immobilized further as bloker. All steps were followed by various characterization techniques such as electrochemical impedance spectroscopy and square wave voltammetry. To generate specific synthetic antibody materials, called MAPS, these were developed with a backside protein-surface imprinting process of the plastic antibody SPAN, the reference of the work. The devices were successfully applied to determine the oxLDL fraction in real serum, without prior dilution or necessary chemical treatment. Overall, these were promising results with the possibility to apply on the practical use of clinical.

Vários estudos que tentam compreender a gênese da aterosclerose têm demonstrado evidências que a oxLDL é peça importante para o desenvolvimento da doença, tornando-a um importante marcador. Os objetivos deste trabalho foram propor um novo imunossensor empregando anticorpos monoclonais anti-oxLDL e desenvolver um processo inovador de obtenção de anticorpos plásticos anti-oxLDL. Para construção do imunossensor, a região Fc do anticorpo foi ligada ao eletrodo de trabalho do dispositivo AuSPE (Screen-Printed Gold Electrodes), utilizando cisteamina. Posteriormente, foi adicionado BSA como bloqueador de possíveis regiões livres. Após o bloqueio, o imunossensor foi testado com oxLDL e outros antígenos, como forma de garantir a especificidade. Em relação aos anticorpos plásticos, chamados MAPS, estes foram desenvolvidos contruindo uma camada impressa de forma invertida ao anticorpo plástico SPAN, referência deste trabalho. Após obtenção dos MAPSs, estes passaram por diversos testes, similar ao imunossensor. Os resultados demonstraram excelente sensibilidade e especificidade às moléculas de oxLDL com detecção em tempo real em ambas as metodologias. / Increased levels of plasma oxLDL are associated with atherosclerosis, and the subsequent development of severe cardiovascular diseases that are today a major cause of death in modern countries. It is therefore important to find a reliable and fast assay to determine oxLDL. A new Immunosensor employing three monoclonal antibodies against oxLDL and a backside protein-surface imprinting process are proposed in this work. To generate the Immunosensor the mAbs were set-up by cysteamine on a gold layer of a disposable screen-printed electrode. BSA was immobilized further as bloker. All steps were followed by various characterization techniques such as electrochemical impedance spectroscopy and square wave voltammetry. To generate specific synthetic antibody materials, called MAPS, these were developed with a backside protein-surface imprinting process of the plastic antibody SPAN, the reference of the work. The devices were successfully applied to determine the oxLDL fraction in real serum, without prior dilution or necessary chemical treatment. Overall, these were promising results with the possibility to apply on the practical use of clinical.

Cette thèse propose une approche rationnelle pour le design de polymères à empreintes moléculaires (MIPs) pour la détection de nitro-explosifs. Les polymères à empreintes moléculaires qui miment la reconnaissance moléculaire biologique, ont l’avantage d’être stables dans des environnements sévères et peuvent adopter différentes formes physiques pour le couplage avec des transducteurs. Leur synthèse est basée sur la co-polymérisation de monomères fonctionnels et réticulants en présence de la molécule cible, ou comme dans cette thèse, d’un analogue ayant une structure proche de celle de la molécule cible. Cela conduit à la formation d’un réseau polymérique tridimensionnel rigide avec des sites de liaison complémentaires en taille, forme et position des groupes fonctionnels de la molécule cible ou de l’analogue. Pour identifier le meilleur monomère fonctionnel pour notre molécule cible, une approche rationnelle basée sur la modélisation moléculaire, la résonance magnétique nucléaire (RMN) et le titrage par calorimétrie isotherme (ITC) a été utilisée. Elle permet d’optimiser le mélange de pré-polymérisation pour identifier le monomère fonctionnel interagissant le plus fortement avec la molécule cible. Les résultats obtenus ont été confrontés à des études de liaison à partir de polymères synthétisés. La formulation polymérique ainsi conçue est intégrée aux surfaces du transducteur sous forme de nanoparticules, de films et de nanoparticules incorporés dans des films de polydopamine électropolymérisés. En plus des polymères traditionnels obtenus par polymérisation radicalaire classique sous forme de particules, des films de MIP à base de polydopamine électropolymérisés ont été étudiés en tant qu'approche alternative pour la détection électrochimique de nitro-explosifs. / This thesis proposes a rational design approach towards molecularly imprinted polymers (MIPs) for sensing nitro-explosives. Molecularly imprinted polymers are mimicking biological molecular recognition. They have the advantage to be stable in harsh environments and can be tailored into different physical forms for interfacing with transducers. Their synthesis is based on the co-polymerization of functional and cross-linking monomers in the presence of the target analyte or, as in this thesis, with a structural analogue leading to a rigid three-dimensional polymer network with binding sites complementary to the template in size, shape and position of the functional groups. The choice of the functional monomer was carried out with a rational design approach combining molecular modelling, nuclear magnetic resonance (NMR) and isothermal calorimetry (ITC) studies. This allows to optimize the pre-polymerization mixture in order to get strong complexation between the functional monomer and the template. The obtained results were confronted with binding studies performed on synthesized polymers. The thus designed polymer formulation was interfaced with transducer surfaces in form of nanoparticles, films and nanoparticles embedded into electro-polymerized polydopamine films. In addition to the traditional MIPs by free radical polymerization, molecularly imprinted in-situ electro-polymerized polydopamine films were investigated as an alternative approach for sensing nitro-explosives electrochemically.

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.