Ce travail vise non seulement à la conception et la fabrication de nouvelles puces microfluidiques pour l'oxydation de l'alcool benzylique, mais aussi au développement d'une méthode utilisant le plasma. Cette dernière est consacrée à la fonctionnalisation de surface avec un liant afin d'ancrer des particules de catalyseur. Les résultats montrent que le procédé PECVD est une méthode universelle permettant de déposer un nombre élevé de fonctions amines à partir de l’APTES sur différentes surfaces. Suite à l’étude des différents paramètres, des conditions optimales ont été trouvées. En effet, par rapport à la fonctionnalisation conventionnelle par voie humide, une meilleure hydrophilicité, une épaisseur de dépôt ainsi qu’une densité de groupements amines plus élevées ont été obtenus sur les échantillons traités. De plus, les résultats avec les AuNPs immobilisés sur la zéolite indiquent que l’APTES est un meilleur précurseur que le MPTES car il offre une plus grande teneur en or. Pour la zéolite et AuNPs@zéolite, les particules sont fonctionnalisées à l'aide du CES en tant qu’agent de liaison pour les amines protonées présentes sur la surface du COC ; ce dernier étant prétraité en utilisant le procédé PECVD. Le microréacteur à base d'or présente une sélectivité élevée stable au benzaldéhyde (~94%). Cependant, il montre également une conversion faible d'alcool benzylique (~20%). Le microréacteur type AuNPs@zéolites réalise la meilleure activité catalytique dans notre étude, car une sélectivité élevée par rapport au benzaldéhyde (>99%) est obtenue avec la conversion la plus élevée de l'alcool benzylique (~40%). / This work aims not only at designing and fabricating new microfluidic chips for benzyl alcohol oxidation, but also at developing a methodology of plasma devoted to the surface functionalization with linkage reagent in order to anchor catalyst particles in the next step. Results show that the PECVD method is a universal method that can deposit high amine content of APTES polymerized film on various substrate surfaces. Optimized plasma conditions for APTES deposition were found and lead to a better hydrophilicity of the substrates, a higher coating thickness, as well as a higher amine group density than the conventional wet chemistry method. In addition, the APTES depositions lead to a further higher coverage and amount of AuNPs when the pH value is 6.2. Moreover, the results of immobilizing AuNPs on zeolite indicate that APTES is a better linker than MPTES as it provides a higher amount of gold loading. For zeolite and AuNPs@zeolite deposition, the particles were functionalized with carboxyl group using CES as a linker for bounding the protonated amines on COC surface that is pre-modified using PECVD method. The latter coating is stable in hydrodynamic flows and could be further used in microfluidics. Finally, the gold \Y zeolite \AuNPs@zeolite microreactors are respectively connected into pre-designed microfluidic system. The gold type microreactor exhibits stable high selectivity to benzaldehyde (~94%). However, it also shows relative low benzyl alcohol conversion (~20%). The AuNPs@zeolites type microreactor performs the best catalytic activity in our study as a high benzaldehyde selectivity (>99%) is obtained with the highest benzyl alcohol conversion (~40%).

The purpose of this thesis project is to demonstrate and evaluate an enzyme-linked immunosorbent assay (ELISA) on a paper microfluidic device platform. The integration of ELISA technology onto paper microfluidic chips allows for a quantitative detection of stroke biomarkers, such as glial fibrillary acidic protein (GFAP). Dye experiments were performed to confirm fluid connectivity throughout the 3D chips. Several chip and housing designs were fabricated to determine an optimal design for the microfluidic device. Once this design was finalized, development time testing was performed. The results confirmed that the paper microfluidic device could successfully route fluid throughout its channels at a reasonable rate. For the biochemistry portion of this thesis project, antibodies were selected to target the intended stroke biomarker: GFAP. However, due to antibody pairing complications, the protein chosen for this project was natural human cardiac troponin T, which is elevated in the bloodstream of patients who have suffered a stroke. Several antibody experiments were performed to help finalize the procedure for performing an ELISA on the paper chip. The final antibody experiment was able to demonstrate that a paper microfluidic device utilizing ELISA techniques can successfully detect a stroke biomarker at physiologically relevant concentrations. Overall, this project supported the ability to accurately and effectively diagnose stroke in a timely manner through the use of a paper microfluidic device.

In this master thesis I have been dealt with the design and construction of an instrumental platform that used positioning focused laser beam (so-called optical tweezers) for manipulation with living cells without their damage.

<div>Rare circulating cells are becoming a subject of interest due to their potential clinical applications to replace invasive procedures. Due their low presence in blood (as low as 1 in 1 ml of blood) various platforms are developed to capture and isolate them. Common limitations of current platforms include the inability to process large volumes of blood without an initial volume reduction step such as centrifugation, reliance on a single antibody for the capture, and the difficulty of releasing and retrieving the captured cells with high purity. A rare cell retrieval platform with high throughput operation and high purity retrieval is needed to capture these rare cells by processing large volumes of blood.</div><div><br></div><div>In this thesis study, we have developed a two-tiered microchip system to capture and retrieve rare cells from blood samples with high purity. The first module of the system is a high throughput microfluidic interface that is used to immunomagnetically isolate targeted rare cells from whole blood, and discard > 99.999% of the unwanted leukocytes. The second module is a microwell array that furthers the purification by magnetically guiding each cell into a separate well concurrently, and allows individual retrieval of each cell. Even though the system we have developed is applicable to many fields pertaining to rare cell capture, here we demonstrate the proof-of-concept using model cell lines that represent circulating fetal trophoblasts. We describe the design, operation as well as the experimental characterization of the system. Our characterization results show that the process can be completed within 145 minutes from the very beginning till the retrieval of a target cell, and can provide efficiencies and purities that are as high as 100%. </div><div><br></div><div>In order to demonstrate a real-world use case for our device, we present preliminary experiments done with blood samples from pregnant women. We show that we are able to retrieve candidate fetal cells under 167 minutes. Future work will be focused on sequencing the candidate fetal cells retrieved from maternal samples to confirm their fetal origin as well as enhancing system performance in maximizing the number of cells captured.</div><div><br></div>

Cette thèse porte sur deux aspects complémentaires, le développement et l’implémentation de nouvelles approches de cristallisation et de cristallographie sérielle ainsi que leur mise en œuvre dans l’étude structurale de complexes enzymes : ARNt. La cristallographie est la méthode la plus employée en biologie structurale, mais elle présente encore des points délicats. Plusieurs méthodes avancées ont été déployées dans ce travail pour y pallier qui ont conduit à la résolution de la structure de l’ARNt nucléotidyltransférase du psychrophile Planococcus halocryophilus et à l’étude de son adaptation structurale au froid ; des puces microfluidiques de cristallisation qui ont servi à la résolution de plusieurs structures à température ambiante par cristallographie sérielle ; enfin le Xtal Controller utilisé pour l’étude d’évènements de nucléation et de croissance cristalline dans un but de préparation d’échantillons pour analyse sous rayonnement XFEL. Entre autres systèmes biologiques, cette thèse présente la caractérisation de deux familles d’inhibiteurs visant les aspartyl-ARNt synthétases, notamment du pathogène Pseudomonas aeruginosa. / This thesis focuses on two complementary aspects, the development and implementation of new approaches of crystallization and of serial crystallography as well as their use in the structural study of enzymes/tRNA complexes. Crystallography is the most used method in structural biology, but it presents delicate points. Different methods were implemented in this work to overcome these points, which led to the resolution of the structure of the CCA-adding enzyme of the psychrophilic organism Planococcus halocryophilus and to the study of its structural adaptation to the cold; novel microfluidic crystallization chips that have been used for the resolution of several structures by serial crystallography at room-temperature; finally the Xtal Controller used for the study of nucleation and crystal growth events with the purpose of preparing samples for analysis under XFEL radiation. Among other biological systems, this thesis presents the study and characterization of two families of inhibitors targeting aspartyl-tRNA synthetases, including the one of the pathogenic organism Pseudomonas aeruginosa.

<p>The development of low-cost, and reliable platforms for on-site detection of pathogenic agents, and toxic environmental traces is still a critical need for real-time monitoring of potential environmental pollution and imminent outbreaks. The biosensors market is projected to attain 31.5 billion by 2024. In this landscape, colorimetric and electrochemical devices continue to have significant relevance, with paper-based platforms leading the point-of-care (POC) segment for pathogen detection and environmental monitoring.</p> <p>Despite the true potential of biosensors in general, they have witnessed a slow rate in commercialization, mainly due to cost restrictions, and concerns related to their reliability and repeatability once scaled-up. This research evaluates the implementation of printing techniques as a strong approach for the fabrication of paper-based and flexible electrochemical biosensors. The results obtained demonstrated the ability to control and predict the variables affecting the sensing performance, achieving high precision of the printing parameters, and allowing optimization, and iterations since very early stages of prototype development.</p> <p>Besides the novel fabrication approach, this work introduces the use of truncated aptameric DNA sequences for whole cell detection of E. coli O157:H7 and heavy metals (Hg2+ and As3+), providing evidence of high stability and robustness under harsh conditions. Results obtained demonstrate their equal or even superior performance when compared to antibodies.</p> <p>We established the use of aptamer-functionalized multilayered label particles (PEI-grafted gold decorated polystyrene) with high stability as label particles. These particles address the well known drawback of non-selective aggregation typical of traditional naked Gold nanoparticles. The outstanding stability of these multilayered labels was demonstrated when used in an enhanced version of the lateral flow assay for detection of E. coli O157:H7 (state of the art for paper-based colorimetric detection of whole cell bacteria), and in a multiplexed paper-based microfluidic device for dual detection of Mercury and Arsenic. This work sets the foundation of the development of a next generation of health care and environmental monitoring devices that are portable, sensitive, quantitative, and can reliably detect multiple targets with one single test.</p>