Gold nanoparticles (AuNPs) have garnered considerable attention for their interesting size-dependent properties. These properties have fueled applications that span a continuum ranging from simple to sophisticated. Applications for these materials have grown more complex as syntheses for these materials have improved. For simple applications, current synthetic processes are sufficient. However, development of syntheses that generate well-defined particle sizes with specifically tailored surface functionalities is an on-going challenge for chemists. The aim of this dissertation is to improve upon current AuNP syntheses to produce sophisticated materials needed to discover new material properties, and provide efficient access to materials to develop new advanced applications. The research described in this dissertation improves upon current methods for AuNP production by using a microreactor to provide enhanced mixing and synthetic control, and small angle X-ray scattering (SAXS) as a precise, rapid, solution-based method for size distribution determination. Using four ligand-stabilized AuNP samples as reference materials, SAXS analysis was compared to traditional microscopic size determination. SAXS analysis provided similar average diameters while avoiding deposition artifacts, probing a larger number of particles, and reducing analysis time. Next, the limits of SAXS size analysis was evaluated, focusing on identifying multiple distributions in solution. Utilizing binary and ternary mixtures of well-defined AuNP reference samples, SAXS analysis was shown to be effective at identifying multiple distributions. While microscopy has limited ability to differentiate these modes, SAXS analysis is more rapid and introduces less researcher bias. Because AuNP size and ligand functionality are interdependent, accessing desired core sizes with varied functionality is challenging. To address this, a new microfluidic synthetic method was developed to produce thiolate-passivated AuNPs with targeted core sizes from 1.5 - 12 nm with tailored functionality. This ability to control size while independently varying surface functionality is unprecedented. Lastly, AuNP core formation was probed by simultaneous in situ SAXS and UV/visible spectroscopy. A coalescence mechanism for AuNP growth was observed when using Bunte salt ligands. This finding compares well to observed coalescence in other systems using weakly-passivating ligands, and supports the hypothesis that Bunte salts passivate ionically during particle growth while resulting in covalent linkages. / 2015-10-10

The rapid advancement of drug delivery systems (DDS) has raised the possibility of using functional engineered nano/micro-particles as drug carriers for the administration of active pharmaceutical ingredients (APIs) to the affected area. The major goals in designing these functional particles are to control the particle size, the surface properties and the pharmacologically active agents release in order to achieve the site-specification of the drug at the therapeutically optimal rate and dose regimen. Two different equipment (i.e. glass capillary microfluidic device and micro-engineered membrane dispersion cell) were utilised in this study for the formation of functional nano/micro-particles by antisolvent precipitation method. This method is based on micromixing/direct precipitation of two miscible liquids, which appear as a straightforward method, rapid and easy to perform, does not require high stirring rates, sonication, elevated temperatures, surfactants and Class 1 solvents can be avoided. Theoretical selection of a good solvent and physicochemical interaction between solvent-water-polymer with the aid of Bagley s two-dimensional graph were successfully elucidated the nature of anti-solvent precipitation method for the formation of desired properties of functional pharmaceutical nano/micro-engineered particles. For the glass capillary microfluidic experiment, the organic phase (a mixture of polymer and tetrahydrofuran/acetone) was injected through the inner glass capillary with a tapered cross section culminated in a narrow orifice. The size of nanoparticles was precisely controlled by controlling phase flow rates, orifice size and flow configuration (two- phase co-flow or counter-current flow focusing). The locations at which the nanoparticles would form were determined by using the solubility criteria of the polymer and the concentration profiles found by numerical modelling. This valuable results appeared as the first computational and experimental study dealing with the formation of polylactide (PLA) and poly(ε-caprolactone) (PCL) nanoparticles by nanoprecipitation in a co-flow glass capillary device. The optimum formulations and parameters interactions involved in the preparation of paracetamol encapsulated nanoparticles (PCM-PCL NPs) using a co-flow microfluidic device was successfully simulated using a 25-full factorial design for five different parameters (i.e. PCL concentration, orifice size, flow rate ratios, surfactant concentration and paracetamol amount) with encapsulation efficiency and drug loading percentage as the responses. PCM-loaded composite NPs composed of a biodegradable poly(D,L-lactide) (PLA) polymer matrix filled with organically modified montmorillonite (MMT) nanoparticles were also successfully formulated by antisolvent nanoprecipitation in a microfluidic co-flow glass capillary device. The incorporation of MMT in the polymer matrix improved the drug encapsulation efficiency and drug loading, and extended the rate of drug release in simulated intestinal fluid (pH 7.4). The encapsulation of MMT and PCM in the NPs were well verified using transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). PCL drug-carrier nanoparticles were also produced by rapid membrane micromixing combined with nanoprecipitation in a stirred cell employing novel membrane dispersion. The size of the NPs was precisely controlled by changing the aqueous-to-organic volumetric ratio, stirring rate, transmembrane flux, the polymer content in the organic phase, membrane type and pore morphologies. The particle size decreased by increasing the stirring rate and the aqueous-to-organic volumetric ratio, and by decreasing the polymer concentration in the aqueous phase and the transmembrane flux. The existence of the shear stress peak within a transitional radius and a rapid decline of the shear stress away from the membrane surface were revealed by numerical modelling. Further investigation on the PCL nanoparticles loaded immunosuppressive rapamycin (RAPA) drug were successfully synthesised by anti-solvent nanoprecipitation method using stainless steel (SS) ringed micro-engineered membrane. Less than 10 μm size of monohydrate piroxicam (PRX) micro-crystals also was successfully formed with the application of anti-solvent precipitation method combined with membrane dispersion cell that has been utilised in the formation of functional engineered nanoparticles. This study is believed to be a new insight into the development of integrated membrane crystallisation system.

En récupération assistée du pétrole (EOR), des mousses sont injectées dans des milieu poreux pour améliorer l’efficacité de l’extraction. L’intérêt est d’éviter les digitations visqueuses, la mousse possédant une forte viscosité effective à faible nombre capillaire (Ca). Les mousses sont produites par co-injection de gaz et de solutions aqueuses de tensio-actifs. Cette thèse se propose de comprendre les mécanismes de formation et de transport de mousse en milieu poreux à travers un micromodèle hétérogène fabriqué en NOA. Les études de formation de mousse sont envisagées de deux manières. La première consiste à étudier une co-injection de deux fluides dans un milieu poreux grâce à un jet généré au centre du système. Cette expérience nous permet de constater qu’une dispersion des deux phases est visible pour des nombres capillaire d’injection plus grand que 10-5. Une deuxième expérience d’injection directe d’un train de bulle dans un milieu poreux montre que les bulles se divisent jusqu’à atteindre un diamètre proche de la taille des pores, pour des Ca suffisamment importants. Par ailleurs, nous avons étudié les propriétés de transport d’une mousse dans un milieu poreux. Des mesures directes montrent que la pression générée par l’écoulement peut être jusqu’à 3000 fois plus importante que la pression due à de l’eau à même débit d’injection pour Ca=10-6. Ce rapport diminue fortement avec le nombre capillaire. Une analyse des chemins parcourus par observation directe souligne que pour des faibles débits relatifs de gaz, seuls quelques chemins sont actifs. Il se trouve cependant qu’une augmentation de Ca ou du débit relatif de gaz conduisent à une homogénéisation du balayage de la mousse dans le milieu. A travers différents modèles de simple canaux droits à section constante ou variable, nous notons que la différence de pression créée par une seule bulle suit la loi de Bretherton en Ca^{2/3}. Cependant, la présence de constrictions conduit à l’existence d’un seuil en pression en-dessous de Ca=2.10-4, et donne lieu à des écoulements intermittents. Enfin, nous présentons des observations de formation et transport de mousse en présence d’huile. Nous constatons alors que la présence d’huile n’a pas d’impact notable pour la solution de tensio-actifs, que ce soit sur la formation ou le transport. / In enhanced oil recovery (EOR), foams are injected in porous media to improve oil recovery efficiency. The objective is to limit viscous fingering thanks to the high effective viscosity of the foam at low capillary number Ca. Foam is produced by the co-injection of a gas and a solution of surfactants. This thesis focuses on foam formation and transport mechanisms in model porous media using a heterogeneous micromodel made in NOA. Foam formation is studied using two different approaches. The first one consists in studying a co-injection of two fluids thanks to a jet flowing in the center of the system. This experiment shows that the less wetting fluids is dispersed in the other one when the capillary number is higher than 10-5. A second set of experiments is conducted by injected a pre-formed train of big bubbles in model a porous media. The bubbles divide until they reach a diameter of the order of to the pore size, for high enough capillary numbers Ca. Besides, we studied the transport properties of foam in similar model porous media. Direct measurements show that the pressure drop induces by the flow can be at Ca=10-6 as high as 3000 times the pressure corresponding to water injected at the same injection flow rate. This ratio decreases with capillary number. An analysis of the preferential paths by direct observations shows that, for low relative gas flow rate, only a few paths are active. However, an increase of the capillary number or if relative gas flow rate leads to a homogenization of the flow in the medium. Thanks to different simple models of straight or wavy channels, we measure that the pressure drop induced by a single bubble is in good agreement with Bretherton’s law, and scales as Ca2/3. However, in wavy channels the pressure drop due to a single bubble deviates from this prediction and exhibits a plateau at Ca lower than 10-4. In this regime, the motion of the bubble is usually intermittent. Finally, we focus on foam formation and transport properties in presence of oil. Our observations lead to the conclusion that for our setup and surfactant formulations, oil has a negligible influence.

Des propriétés électromagnétiques nouvelles peuvent être réalisées à l'aide d'une méta-surface à travers des structures artificielles. La permittivité et la perméabilité effectives d'une méta-surface peuvent être conçues de façon flexible et même accordées de sorte à présenter des réponses électromagnétiques pouvant être très différentes de celles de leurs homologues naturels, ce qui conduit à des propriétés améliorées voire parfois à un comportement extraordinaire. Cette thèse porte sur la conception, la fabrication et l'expérimentation de méta-surfaces micro-fluidiques pour le contrôle de propriétés des ondes électromagnétiques. Leur réalisation est basée sur des technologies relevant de la photolithographie et de la micro-fluidique, mises en œuvre sur des substrats souples d'épaisseur sub-longueur d'onde. Plus spécifiquement, nous avons exploité l'incorporation de divers matériaux dans un réseau de canaux micro-fluidiques, y compris des diélectriques liquides, un métal liquide et un métal solide pour manipuler davantage les réponses électromagnétiques des méta-surfaces correspondantes, telles que l'absorption, la transmission et la chiralité. La première partie de la thèse présente une méta-surface très absorbante sur une ultra-large bande spectrale et. Elle est constituée d'un réseau de résonateurs formés de gouttelettes d'eau noyées dans le matériau diélectrique souple, le PDMS; l’absorption mesurée est presque parfaite sur les bandes Ku, K et Ka. La seconde partie de la thèse porte sur un absorbeur agile et indépendant de l'angle dans la gamme Térahertz ; il s’agit d’une méta-surface à base de métal liquide, où un réseau de puits métalliques liquides dont la hauteur est contrôlée de façon continue, ce qui brise la limitation d'accordabilité dans le plan 2D. La troisième partie de la thèse porte sur une méta-surface chirale active. La méta-surface peut être commutée de achiral à chiral en déformant la structure en spirale initialement plane vers une géométrie 3D. Cette fonctionnalité peut manipuler la transmission hyperfréquence de symétrique à asymétrique sous incidence avant et arrière. En conclusion, l'optimisation de l'absorption, de la transmission et de la chiralité d’ondes électromagnétiques a été réalisée grâce à des méta-surfaces micro-fluidiques, qui semblent ainsi présenter un important potentiel applicatif dans divers domaines tels que la technologie furtive, l'imagerie et la communication optique / Novel and tailored electromagnetic properties can be realized using a metasurface through artificially designed structures. The effective permittivity and permeability of a metasurface can be flexibly designed and even tuned so as to exhibit electromagnetic responses that can be very different from those of their natural counterparts, leading to enhanced properties and sometimes to extra-ordinary behaviour. This thesis focuses on the design, fabrication and experimentation of meta-liquid-based metasurfaces for electromagnetic wave control and modulation. These metasurfaces are based on the use of both photolithography-based microfabrication and microfluidic technologies implemented onto thin and flexible substrates of sub-wavelength thickness. More specifically, the incorporation within a microfluidic channel network of various materials, including liquid dielectric material, liquid metal and solid metal have been exploited to further manipulate the electromagnetic responses of the related metasurfaces, such as the absorption, transmission and chirality. The first part of the thesis reports an ultra-broadband and wide-angle absorbing material by water-resonator-based metasurface. It consists of an array of water droplets embedded in the soft dielectric material, PDMS; it exhibited an almost perfect absorptivity over the Ku, K and Ka bands. The second part of the thesis focuses on a frequency-agile and wide-angle absorber in terahertz by liquid-metal-based metasurface, where a liquid-metal-pillar array can be continuously controlled in the vertical direction hence breaking the tuning limitation in the 2D plane. The third part of the thesis focuses on an active chiral metasurface. The metasurface can be switched from achiral to chiral by changing the spiral structure from planar pattern to 3D pattern. This functionality can manipulate the microwave transmission from symmetric to asymmetric under forward and backward incidence. In conclusion, tunability on the absorption, transmission and chirality have been realized through microfluidic metasurfaces, which appear having high potential applications in various areas such as stealth technology, imaging system, and optical communication, to name a few

abstract: Complex samples, such as those from biological sources, contain valuable information indicative of the state of human health. These samples, though incredibly valuable, are difficult to analyze. Separation science is often used as the first step when studying these samples. Electrophoretic exclusion is a novel separations technique that differentiates species in bulk solution. Due to its ability to isolate species in bulk solution, it is uniquely suited to array-based separations for complex sample analysis. This work provides proof of principle experimental results and resolving capabilities of the novel technique. Electrophoretic exclusion is demonstrated at a single interface on both benchtop and microscale device designs. The benchtop instrument recorded absorbance measurements in a 365 μL reservoir near a channel entrance. Results demonstrated the successful exclusion of a positively-charged dye, methyl violet, with various durations of applied potential (30 - 60 s). This was the first example of measuring absorbance at the exclusion location. A planar, hybrid glass/PDMS microscale device was also constructed. One set of experiments employed electrophoretic exclusion to isolate small dye molecules (rhodamine 123) in a 250 nL reservoir, while another set isolated particles (modified polystyrene microspheres). Separation of rhodamine 123 from carboxylate-modified polystyrene spheres was also shown. These microscale results demonstrated the first example of the direct observation of exclusion behavior. Furthermore, these results showed that electrophoretic exclusion can be applicable to a wide range of analytes. The theoretical resolving capabilities of electrophoretic exclusion were also developed. Theory indicates that species with electrophoretic mobilities as similar as 10-9 cm2/Vs can be separated using electrophoretic exclusion. These results are comparable to those of capillary electrophoresis, but on a very different format. This format, capable of isolating species in bulk solution, coupled with the resolving capabilities, makes the technique ideal for use in a separations-based array. / Dissertation/Thesis / Ph.D. Chemistry 2012

Orientador: Jarbas Jose Rodrigues Rohwedder / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-10T02:35:04Z (GMT). No. of bitstreams: 1 Killner_MarioHenriqueMontazzolli_M.pdf: 2163718 bytes, checksum: 57b0452d9c198120c39d7c2faffd08e3 (MD5) Previous issue date: 2007 / Resumo: O presente trabalho descreve o desenvolvimento de um sistema voltametrico microfluidico, de um potenciostato de baixo custo e de um programa computacional para controle do potenciostato e aquisição de dados. O sistema voltamétrico microfluídico foi confeccionado empregando dois fotopolímeros, sendo um sólido e outro líquido. Foi também avaliado o uso de uma resina acrílica. Técnica de litografia utilizando radiação UVA foi empregada para a confecção dos protótipos. O fotopolímero líquido, a base de uretano-acrilato, apresentou as melhores características como flexibilidade, fácil manuseio e boa selagem dos canais analíticos. Estes canais foram confeccionados com largura de 600 mm e profundidade de 100 mm. O eletrodo de trabalho foi construido empregando um fio de platina de 75 mm de diâmetro e 1,5 mm de comprimento. Uma agulha de aço inox de 13 mm de comprimento e 0,45 mm de diametro foi empregada como eletrodo auxiliar e um fio de prata de 600 mm de diâmetro e 2,0 mm de comprimento recoberto com cloreto de prata foi utilizado na construção do eletrodo de referência. Os resultados de voltametria cíclica para soluções de diferentes concentrações de FeK4(CN)6 obtidos utilizando o sistema desenvolvido foram semelhantes aqueles obtidos empregando um potenciostato comercial. A determinação de Pb(II) em uma amostra certificada (452,2 mg L) apresentou um erro relativo de -3,9% e desvio relativo de 2,0% (n=3) empregando voltametria de redissolução anódica com varredura de onda quadrada / Abstract: The present work describes the development of a microfluidic voltammetric system, a low cost potentiostat, and a software used for data acquisition and control of the potentiostat. The microfluidic voltammetric system was formed using two photopolymers, one solid and one liquid. In addition, the use of an acrylic resin was evaluated. The photolitography using UVA radiation was used for the fabrication of prototypes. The liquid polymer of urethane-acrylate showed better characteristics such as flexibility, easy manipulation and good sealing of the analytical channels. The analytical channels were 600 mm width and 100 mm depth. The work electrode was made of a platinum wire of 75 mm of diameter and 1,5 mm of length. A stainless steel needle 13 mm long and with 0,45 mm of diameter was employed as auxiliary electrode and a silver wire of 600 mm of diameter and 2,0 mm long covered with AgCl was employed as reference electrode. The results obtained using Cyclic Voltammetry for solutions of different concentrations of FeK4(CN)6 and the developed system were similar to those obtained using a commercial potentiostat. The determination of Pb(II) in a certificated sample of water (452,2 mg L) showed a relative error of ¿3,9% and a relative standard deviation of 2,0% (n=3) employing anodic stripping voltammetry and square wave potential scan / Mestrado / Quimica Analitica / Mestre em Química

Orientadores: Rosiane Lopes da Cunha, Fernanda Yumi Ushikubo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-24T20:14:36Z (GMT). No. of bitstreams: 1 Oliveira_DaviRochaBernardesde_M.pdf: 18877035 bytes, checksum: 1668d21b0c81ea31f26e9d7c85a25644 (MD5) Previous issue date: 2014 / Resumo: A emulsificação em dispositivos microfluídicos destaca-se pela sua capacidade em gerar gotas de maneira individual em um processo totalmente controlado. Através dele, é possível a obtenção de emulsões com coeficientes de variação de tamanho de gotas inferiores a 5%. Soluções de glicerol (fluidos Newtonianos) com concentrações variando entre 10 e 75% (m/m) foram utilizadas como fase dispersa para obtenção de emulsões água em óleo em microcanais planares com junções do tipo T e Y. Como fase contínua foi utilizado óleo de soja contendo 5% (m/m) de emulsificante PGPR. Como condições de processo, quatro diferentes razões entre as vazões das fases contínua e dispersa foram avaliadas. Paralelamente, quatro soluções de goma xantana (fluidos não-Newtonianos) com concentrações variando de 0,05 a 0,50% (m/m) foram avaliadas como fase dispersa num microcanal com junção em Y, e submetidas às mesmas condições das soluções de glicerol. Em todos os sistemas avaliados, a razão entre as fases foi o fator de maior influência no tamanho das gotas formadas. Em relação aos fluidos Newtonianos, a emulsificação no canal em T se mostrou menos sensível às propriedades físicas dos fluidos, enquanto na geometria em Y, notou-se, através do cálculo dos números adimensionais de Weber e Capilar, grande influência da tensão interfacial sobre o tamanho das gotas formadas, superando a ação das forças viscosas. Em relação aos fluidos não-Newtonianos, foi observada grande diferença no processo de formação das gotas e nas características da emulsão. Gotas com elevada polidispersão foram obtidas, em especial nas soluções mais concentradas e nas maiores razões entre as vazões das fases. Esse fato se deu devido à formação das gotas ter ocorrido longe da junção dos canais, através da formação de um jato de fase dispersa. Esse jato foi intensificado nas soluções de goma xantana de maior concentração e nas condições de maiores velocidades da fase contínua. Ensaios reológicos extensionais confirmaram que, de fato, a viscosidade elongacional da solução de goma xantana aumenta com a concentração e também com a taxa de deformação elongacional, o que explicaria a formação do jato. Na solução de menor concentração de goma xantana foi possível a obtenção de gotas altamente monodispersas, embora tenha ocorrido a formação do jato no rompimento das gotas, estando essa solução numa região de transição do regime de jateamento para o regime de gotejamento. Dessa forma, pode-se verificar que no regime de gotejamento, típico dos fluídos Newtonianos, a monodispersão é uma característica bem definida. No caso do uso de fluídos viscoelásticos na fase dispersa, a obtenção de gotas monodispersas é um desafio, devido ao efeito da elevada viscosidade elongacional. Assim, torna-se necessária a avaliação de condições de processo e geometria de canal mais adequadas a esta situação de forma a diminuir a polidispersidade desses sistemas / Abstract: Emulsification in microfluidic devices is distinguished by its ability to generate droplets in a controlled and individual way, in which it is possible to obtain emulsions with polydispersity lower than 5%. Glycerol solutions (Newtonian fluids) at concentrations ranging from 10 to 75% (w/w) were used as dispersed phase in order to obtain water in oil emulsions, using Y - and T - junction microchannels. As continuous phase, soybean oil containing 5% (w/w) of emulsifier PRPG was used. Four different ratios of the flow rates of continuous and dispersed phases were evaluated in both microfluidic devices. Similarly, four xanthan gum solutions (non-Newtonian fluids) with concentrations ranging from 0,05 to 0,50% were evaluated as dispersed phase in a Y ¿ junction microchannel. In all systems, the ratio of the flow rates of the phases was the most influential factor in the size of the droplets. Regarding Newtonian fluids, the T ¿ junction microchannel was less sensitive to the fluids physical properties, while in Y ¿ junction geometry it was noted that the interfacial tensions played the main role in droplet size, overcoming the viscous forces. Regarding the non-Newtonian fluids, a large difference in the droplet generation was observed. Droplets with high polydispersity were obtained, especially in the most concentrated xanthan gum solution, when high shear forces were applied. This fact may have occurred due to the formation of a jet of the dispersed phase, from which droplets were detached without any control. This jet was intensified in xanthan solutions of higher concentration and under high velocities of the dispersed phase. Indeed, extensional rheology confirmed that the elongational viscosity of xanthan gum solution increases with concentration and also with the rate of elongational deformation, which would explain the formation of the jet. In the solution at lower concentration of xanthan, it was possible to obtain highly monodisperse droplets, although the droplets detachment still occurred in the jetting regime. This solution is herefore in a transition region between jetting and dripping regime. Thus, it was verified that the dripping regime, typical of Newtonian fluids, the monodispersity is a well-defined characteristic. On the other hand, when using viscoelastic fluids as dispersed phase, obtaining monodispersed droplets is still a challenge, due to the effect of high elongational viscosity of this fluids. In this way, it becomes necessary evaluate new process conditions and microchannel geometries in order to reach emulsions with low polydispersity / Mestrado / Engenharia de Alimentos / Mestre em Engenharia de Alimentos

Three major topics will be discussed in this dissertation. The first is an optical biosensor for specific diagnosis of bacterial skin and wound infection, followed by a paper microfluidic assay and accompanying monitoring device for monitoring blood coagulation and determining patient-specific heparin and protamine dosing. The final work to be discussed is ongoing work involving the detection of circulating tumor cells (CTCs) using a paper microfluidic detection platform. All of these works involve the development of biosensors for the simultaneous advancement and simplification of diagnosis and analysis of blood and bacterial infection. The aims of each of these projects included significantly decreasing the time to diagnosis and decreasing the reagents, laboratory space, personnel, and other resources needed for detection and diagnosis. The first works are focused on the design, development, and testing of an optical biosensor for the immediate detection of bacterial skin and wound infection, including diagnosing the specific species of bacteria responsible for the infection. The optical biosensor developed allows for diagnosis of a bacterial infection on skin or in a wound in as little as three seconds, in a contact-free, reagent-free manner. The second work focused on the design, development, and testing of a paper microfluidic assay and accompanying Raspberry Pi-based monitoring device for use before, during, and after surgeries requiring the use of cardiopulmonary bypass. The assay monitors the extent of blood coagulation of a whole blood sample and determines patient-specific dose response curves of an anticoagulant and its reversal agent. The final work discussed focuses on developing a paper microfluidic assay for the detection of CTCs from whole blood samples. The goal of this work is to detect multiple morphologies of CTCs from whole blood samples to provide insight on patient prognosis in a rapid, low resource manner.

La fécondation est la rencontre de deux gamètes. Bien que centrale chez les espèces sexuées, les mécanismes membranaires et moléculaires ne sont pas encore établis. La communauté scientifique bute toujours sur la question centrale : Comment le spermatozoïde fusionne-t-il avec l’ovule ? Si des études ont identifié trois protéines essentielles : Izumo1, Juno et CD9, elles montrent aussi que ces acteurs ne sont pas suffisants. Notre étude a eu pour but d’identifier d’autres paramètres potentiels impliqués dans cette machinerie de fusion. Nous nous sommes donc focalisés sur la contribution des lipides spermatiques et sur celle du battement du flagelle. Nous avons développé deux méthodes expérimentales originales. Avec la première, qualifiée de « Bottom-up », nous avons tenté de déterminer la machinerie spermatique minimale pour induire la fusion avec l’ovocyte. L’idée a été de reconstituer pas à pas la membrane de la tête du spermatozoïde, d’abord avec les lipides identifiés lors d’analyses, puis en y incorporant Izumo1. Pour la seconde approche, appelée « Top-down », nous avons développé un outil microfluidique pour guider le spermatozoïde jusqu’à l’ovocyte afin de suivre la rencontre avec le « meilleur » point de vue, dans des conditions in-vitro aussi physiologiques que possible. Nous avons découvert que contrairement à ce que nous pensions, le battement du flagelle ne sert pas uniquement à atteindre l'ovocyte, mais aussi à déclencher la fécondation. En effet, les contraintes mécaniques induisent une réorganisation de la membrane ovocytaire incluant la protéine CD9. Ainsi, la chronologie des événements a pu être obtenue avec une résolution temporelle inégalée. / Fertilization is the encounter of two gametes. Although this process is crucial for sexual organisms, the timeline of the molecular events is not yet established. The researchers cannot explain: how the spermatozoon fuses with the oocyte? One of the reasons is the lack of experimental methods available. Indeed, the gametes need a specific environment to fertilize. Nevertheless, the scientific community identified three essential proteins: Izumo1 on the spermatozoon, Juno (its receptor) and CD9 on the oocyte membrane. For our part, we tried to determine if the none-proteins environment of Izumo1 and CD9 could influence the gametic interaction. To do so, we were focused on the role of the lipids composition of the sperm membranes and on the influence of the forces developed by the flagellum beating on the oocyte. We designed two original experimental methods to offer a better understanding of the mechanisms inside the gamete contact area. With the first one, we tried to identify the minimal machinery to induce fusion. We started to reconstitute step by step the membrane of the spermatozoon head. We tested first the identified lipids alone, and then we coupled these molecules with Izumo1. With the second one, we developed a microfluidic tool to observe the gametic encounter with the “best” viewpoint in the most physiological in-vitro conditions. We observed that the flagellum beating is not only involved in the crossing of the female genital tract but also in the initiation of the fusion step. Indeed, the mechanical constraints induce membrane reorganization with CD9 recruitment. So we succeed to establish the kinetic of the events with an unequaled resolution.

The miniaturization afforded by the integration of microfluidic technologies within lab-on-a-chip devices has greatly enhanced analytical capabilities in several key applications. Microfluidics has been utilized in a wide range of areas including sample preparation and analysis, DNA microarrays, cell detection, as well as environmental monitoring. The use of microfluidics in these applications offer many unique advantages: reduction in the required sample size, reduction in analysis time, lowered cost through batch fabrication, potentially higher throughput and the vision of having such devices used in portable systems. Nanopore sensors are a relatively new technology capable of detection and analysis with single-molecule sensitivity, and show promise in many applications related to the diagnosis and treatment of many diseases. Recently, some research groups demonstrated the integration of nanopores within microfluidic devices to increase analytical throughput. This thesis describes a methodology for integrating nanopore sensors within microfluidic devices with the aim of enhancing the analytical capabilities required to analyze biomolecular samples. In this work, the first generation of an integrated nanopore-microfluidic device contained multiple independently addressable microfluidic channels to fabricate an array of nanopore sensors using controlled breakdown (CBD). Next, for the second generation, we added pneumatic microvalves to manipulate electrical and fluidic access through connected microfluidic channels. As a proof-of-concept, single molecules (single- and double-stranded DNA, proteins) were successfully detected in the devices. It is also demonstrated that inclusion of the microfluidic via (microvia) limited the exposed area of the embedded silicon nitride membrane to the solution. This helped in localizing nanopore formation by confining the electric field to specific regions of the insulating membrane while significantly reducing high frequency noise in the ionic current signal through the reduction of chip capacitance. The devices highlighted in this thesis were designed and fabricated using soft lithography techniques which are available in most biotechnology laboratories. The core of this thesis is based on two scientific articles (Chapters 3 and 4), which are published in peer-reviewed scientific journals. These chapters are preceded by an introductory chapter and another chapter detailing the experimental setup and the methods used during the course of this study.