Immobilization of fluorescent chemosensors and chromogenic reagents on solid supports for developing optical sensors result in improved analytical performance characteristics such as continuous read-out, increased sensitivity, lower reagent consumption and possibility of using the sensor in solvents where the free molecule displays low solubility. The aim of this study is to immobilize dansylaminophenyl boronic acid (DAPB acid) and diphenylcarbazide (DPC) into various solid supports for the determination of fructose and hexavalent chromium, respectively. DAPB acid reacts with diol containing molecules to produce electron transfer resulting fluorescence quenching. Whereas DPC reacts specifically with chromate to produce a magenta colored complex having absorption maximum at 540 nm. Utilizing sol-gel technology, inorganic polymer matrices which enabled to observe fluorescence and absorbance signal in VIS region has been constructed. Also methylmethacrylate (MMA) and methacrylic acid (MAA), which are known to give transparent organic co-polymers, are chosen as monomers in the synthesis of organic copolymer. Hydrogels such as polyvinyl alcohol and Ca-alginate gel have been utilized for their good optical characteristics in the working range. Several considerations in the construction of host matrix were taken into account, such as the porosity of the polymers, functionalization of the matrix and use of additives for increasing the affinity of the medium toward the dopant molecule and swelling properties of organic polymers. The performances of the immobilizations were evaluated in terms of the transmittance and leaching properties of the host matrix, optical properties of dopant and optical response characteristic of the dopant for the analyte. The sensor applications of the immobilized probe molecule DPC were investigated. Studies regarding the enhancement of the performance of the flow injection analysis method for fructose determination, previously carried out in our laboratory, based on the fluorescence quenching of DAPB acid probe in solution were stated.

La détection sensible et sélective des métaux lourds, en particulier les métaux detransition, est d’une grande importance pour la santé publique ainsi que pour la surveillancede l’environnement. Les méthodes actuelles de référence, de par leur non portabilité, limitentla possibilité de disposer de mesures à haute résolution spatiale et temporelle. Lesmicrocapteurs optiques offrent un moyen attrayant et pratique pour surmonter ces limitationsde coût global et de temps d’analyse, en permettant la mesure en temps réel sur site.Pour démontrer ce potentiel, ces travaux de thèse sont orientés sur la détermination duchrome hexavalent Cr(VI) en solution à l’aide d’une réaction colorimétrique avec le 1,5-diphénylcarbazide (DPC), permettant de créer un complexe présentant un maximumd’absorption dans le domaine du visible. Ces travaux s’inscrivent dans la volonté dedévelopper un véritable laboratoire sur puce, intégrant la fonction fluidique parélectromouillage sur diélectrique pour créer la réaction colorimétrique, ainsi que la fonctionde mesure par intégration d’un capteur optique dédié à la mesure d’absorption dans desmicrovolumes (< μL). Pour la mesure d'absorption sur de si faibles volumes, l'utilisation demicrorésonateurs vise à augmenter de façon importante le chemin optique effectif et ainsi lasensibilité du capteur.Nous décrivons nos travaux sur la conception, la fabrication de la plateformemicrofluidique digitale ainsi que du résonateur optique en anneaux à des dimensionssubmicroniques par photolithographie par projection. Les matériaux polymères sontprivilégiés pour une intégration totale bas coût à terme, ainsi qu’un substrat verre, dont lespropriétés sont particulièrement adaptées aux applications optiques dans le domaine duvisible. / The selective and sensitive detection of heavy metals, such as transition metals, is ofparamount importance for health and safety an environmental monitoring. Current referencemethods, due to their lack of portability, are limiting factors to obtain high-resolution spatialand temporal data. Optical sensors offer an attractive and convenient way to overcome theselimitations of cost and time per analysis by offering real time, on-site measurementcapabilities.In order to demonstrate this potential, this thesis is focused on the detection and quantificationof hexavalent chromium Cr(VI) in water samples by a colorimetric reaction based on areaction with the 1,5-diphenylcarbazide (DPC), that produces a complex possessing anabsorption maximum in the visible range. This works endorse the goal of creating a true labon-chip, integrating both the fluidic function based on ElectroWetting on Dielectric (EWOD)to create the colorimetric reaction, and the sensing function based on the integration of anoptical sensor able to measure absorption variations in micro-volumes (< μL). In order toobtain sufficient sensitivity on such small volumes, optical microring resonators are used inthis work, due to their ability to enhance the effective optical path length by constructiveinterferences.This thesis describes the conception and fabrication of the EWOD microfluidic platform, aswell as the conception, simulation and fabrication of submicronic microring resonators usingstepper lithography. Polymer materials and glass substrates are selected, due to their greatoptical properties in the visible range, their compatibility with the EWOD platform, and theirintegrability at a reasonable cost.