Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Il existe un besoin industriel croissant de nouvelles technologies capables de manipuler des objets à l’échelle micrométrique (1-1000 μm). Dans cette thèse, une technique originale d’actionnement sans contact pour la manipulation d’objets à l’échelle micrométrique est proposée. Elle est basée sur les écoulements thermocapillaires convectifs induits par un laser pour manipuler des particules à l’interface fluide/gaz. Le laser chauffe localement la surface de l’eau, ce qui induit un gradient de tension de surface. Ce gradient génère un écoulement fluidique. Ces écoulements sont rapides et localisés, ce qui confère des performances intéressantes à cette technique d’actionnement. Les particules sont manipulées à l’interface fluide/gaz, où l’écoulement généré est le plus rapide.Pour assurer le positionnement précis d’une particule, des contrôleurs en boucle fermée sont implémentés dans le système. Ils sont basés sur les modèles développés dans cette thèse. Des essais expérimentaux montrent que le positionnement précis de particules peut être assuré. De plus, les forces d’interaction entre des particules placées à l’interface ont été étudiées, et une stratégie de contrôle a été proposée, en vue de la manipulation en parallèle de plusieurs particules. Tant les études analytiques et les simulations numériques que les tests expérimentaux soulignent l’intérêt des écoulements thermocapillaires pour la manipulation contrôle d’objets micrométriques. Cette technique est donc une alternative prometteuse aux approches classiques d’actionnement sans contact. / There is an industrial need for new technologies that can manipulate objects in the micrometric scale (1-1000 μm). In this thesis, an original non-contact actuation technique for the manipulation of microscale objects is proposed. The proposal is to use laser-induced thermocapillary convective flows to manipulate particles at the fluid/gas interface. These flows are generated when a surface tension stress is generated at the fluid/gas interface due to a thermal gradient. Laser heating is used because the generated thermal gradients produce fast, localized flows that improve the actuation performance. The particles are manipulated at the interface because the flow generated there is the fastest in the entire fluid.To ensure the precise positioning of a particle, closed-loop controllers are implemented in the system which are designed based on models proposed for the system. Experimental tests are performed that show that positioning precision can be ensured. In addition, the interaction forces between particles have been studied which is a preliminary step towards parallel manipulation. To counteract those forces during the manipulation, a different control strategy has been proposed, implemented and tested. Overall, the results obtained are comparable to the ones obtained with the other techniques. Therefore, the proposed technique can be considered as an attractive alternative that offers different advantages and disadvantages.

La macro-autophagie est un processus de dégradation intracellulaire qui impliquela formation d'une vésicule à double membranes, l'autophagosome, permettantla séquestration des molécules à dégrader. La formation de l'autophagosome dé-bute par la nucléation de membranes isolées dans le cytosol. Elle se poursuit parune phase de croissance de la membrane en forme de coupe. Dans l'étape _nale,l'autophagosome se referme en fusionnant par ses bords pour former la vésicule.La morphologie de l'autophagosome évolue donc durant sa formation. Certainesétudes montrent que cela est dû à l'implication de machineries protéiques. Indé-pendamment, d'autres recherches mettent en avant les rôles joués par les propriétésphysiques de la membrane.Dans mon travail de thèse, j'ai cherché à montrer un couplage entre l'activité d'uneprotéine impliquée dans l'autophagie et les caractéristiques physiques de la membrane.Cette protéine, nommée GABARAP, est considérée comme le marqueurde l'autophagosome car elle est la seule protéine, avec ses homologues, à s'ancrerspécifiquement sur sa membrane lors de sa formation. En incorporant GABARAPdans des vésicules géantes unilamellaires micromanipulées, j'ai pu montrer unein_uence de la composition et de la courbure de la membrane sur la distribution,l'oligomérisation et la dynamique de la protéine. Ensuite, j'ai mesuré une diminutiondu module de courbure de la membrane lorsque la protéine y était ancrée.Cette dernière étude m'a amenée à développer un modèle permettant de prédire ladistribution de la protéine sur une membrane possédant deux régions de courburesdiérentes. Enfin, j'ai déterminé la nature de l'interaction en trans de GABARAP. / Macro-autophagy is an intracellular degradation process that involves a doublemembrane vesicle, the autophagosome, to engulf a cargo. Its formation starts withthe nucleation of isolated membrane in the cytosol. Then the membrane growsas a cup-shape around the cargo to finally fuse at its edge and enclose the molecules to be degraded. Thus, the autophagosome morphology evolves during itsformation. Studies show that protein machineries support such shape changes. Independently, other researches point membrane physical properties roles during itsrearrangement.During my PhD, I investigated the coupling between the activity of one autophagyprotein and membranes physical characteristics. This protein, GABARAP,is considered as the autophagosome marker, because, with its homologs, it is theonly protein to be specifically anchored to its membrane during all its formation.The reconstitution of GABARAP in micromanipulated giant unilamellar vesicles(GUVs) allowed me to study the interplay between membrane characteristics andprotein behaviours. In a first part, I showed that membrane composition and curvature trigger specific distribution, oligomerization and dynamic of GABARAP.Then I measured a decrease of the membrane bending modulus when the proteinwas anchored. This last result led me to propose a model that predicts proteinsdistribution on membranes with two regions of diferent curvatures. Finally, I determined the nature of GABARAP / GABARAP trans interaction.

Physical pick-and-place promises specificity, precision, and programmed motion, a feature making microrobotic manipulation amenable to automation for the construction of microsystems. Despite the significant progress made, a long-standing difficulty is the release of micro objects from the end effector due to strong adhesion forces at the micro scale. This research focuses on the development of microelectromechanical systems (MEMS) based microgrippers that integrate an active release mechanism for pick-and-release micromanipulation. The performance was experimentally quantified through the manipulation of 7.5-10.9µm glass spheres, and for the first time, achieves a 100% success rate in release (based on 700 trials) and a release accuracy of 0.45±0.24µm. Example patterns were then constructed through automated microrobotic pick-and-place of microspheres, achieving a speed of 6sec/sphere. To further miniaturize the devices for nanomanipulation, a novel fabrication process was developed. Through the manipulation of 100nm gold nano-particles inside a scanning electron microscope (SEM), preliminary demonstrations were made.

Physical pick-and-place promises specificity, precision, and programmed motion, a feature making microrobotic manipulation amenable to automation for the construction of microsystems. Despite the significant progress made, a long-standing difficulty is the release of micro objects from the end effector due to strong adhesion forces at the micro scale. This research focuses on the development of microelectromechanical systems (MEMS) based microgrippers that integrate an active release mechanism for pick-and-release micromanipulation. The performance was experimentally quantified through the manipulation of 7.5-10.9µm glass spheres, and for the first time, achieves a 100% success rate in release (based on 700 trials) and a release accuracy of 0.45±0.24µm. Example patterns were then constructed through automated microrobotic pick-and-place of microspheres, achieving a speed of 6sec/sphere. To further miniaturize the devices for nanomanipulation, a novel fabrication process was developed. Through the manipulation of 100nm gold nano-particles inside a scanning electron microscope (SEM), preliminary demonstrations were made.

The scope of this thesis is micromanipulation in liquid media. This scientific field aims at understanding the relevant phenomena existing during the manipulation in a liquid of microcomponents having a size between $1,micrometer$ and a few millimeters. This work focuses on the study of surface tension forces in immersed media, because they have favorable scaling effect. The main idea is to use gas bubbles as actuation mean in a liquid, and requires to study the mechanical properties of these bubbles. The originality of the approach is the combination of two effects: surface tension and gas compressibility. The first step was the study of an efficient mean to generate a single bubble of predefined size. After a detailed review, it appeared that volume controlled bubble generation was a promising method. We have then developed a model to predict the size of a bubble, and emphasized the possible existence of a growing instability. An analytic dimensionless study allowed to define a criterion to predict the existence of this instability. The second step aimed at the mechanical characterization in quasi static equilibrium of a gas bubble caught between two solids. The purpose is to predict the force generated by the bubble, together with its stiffness. The model implemented allowed to infer interesting properties, notably a high compliance whose value is controllable by fluidic parameters. This compliance property being very important during micromanipulation, a demonstrator making use of gas bubbles has been designed and manufactured. It consists in a compliant microtable actuated by three bubbles. This work opens the way to new actuation or sensing means, using the transduction between fluidic and mechanic energy operated by a capillary bridge. / Cette thèse a pour contexte la micromanipulation en milieu liquide. Cette thématique scientifique vise à comprendre les phénomènes qui interviennent lors de la manipulation dans un liquide de microcomposants, dont la taille peut varier entre $1,micrometer$ et quelques millimètres. Les travaux de cette thèse se sont focalisés sur l'étude des forces de tension de surface en milieu immergé, car elles bénéficient d'effets d'échelle favorables. L'idée poursuivie est d'utiliser des bulles de gaz comme un moyen d'actionnement dans les milieux liquides, et nécessite d'étudier les propriétés mécaniques de ces bulles. L'originalité de l'approche repose sur la combinaison de deux effets : la tension de surface et la compressibilité du gaz. La première étape a été l'étude d'un moyen efficace pour générer une unique bulle de gaz de taille voulue. Après une analyse exhaustive, il est apparu que la génération de bulle par le contrôle en volume était une méthode prometteuse. Nous avons alors développé un modèle permettant de prédire la taille d'une bulle, et mis en évidence la possible existence d'une instabilité de la croissance de ces bulles. Une étude analytique adimensionnelle nous a permis de définir un critère pour prédire l'existence ou non de cette instabilité. La seconde étape a porté sur la caractérisation mécanique en régime quasi statique d'une bulle de gaz en contact avec deux solides. Le but étant de prédire la force générée par une bulle de gaz sur les solides ainsi que sa raideur. Le modèle implémenté a permis de déduire des propriétés intéressantes des bulles de gaz, notamment une grande compliance dont la valeur peut être contrôlée par des paramètres fluidiques. Cette propriété de compliance étant très recherchée en micromanipulation, un démonstrateur exploitant les bulles de gaz a été conçu. Il s'agit d'une microtable compliante actionnée par trois bulles. Ces travaux ouvrent la voie vers de nouveaux modes d'actionnement ou de capteur utilisant la transduction entre une énergie fluidique et mécanique opérée par un ménisque capillaire.

The introduction of microassembly technologies has opened up new venues for the fabrication of sophisticated, three-dimensional Microelectromechanical System (MEMS) devices. This thesis presents the development of a robotic micromanipulation system and its controller algorithms for conventional pick-and-place microassembly processes. This work incorporated the approach of parallel assembly and automation to improve overall productivity and reduce operating costs of the process. A parallel set of three microgrippers was designed and implemented for the grasping and assembly of three microparts simultaneously. The complete microassembly process was automated through a vision-based control approach. Visual images from two vision systems were adopted for precise position evaluation and alignment. Precise alignment between the micropart and microgripper is critical to the microassembly process. Due to the limited field of view of the vision systems, the micropart could displace away from the microscope field of view during the re-orientation process. In this work, a tracking algorithm was developed to constrain the micropart within the camera view. The unwanted translational motions of the micropart were estimated. The algorithm then continuously manipulated and repositioned the micropart for the vision-based assembly. In addition, the limited fields of view of the vision systems are not sufficient to concurrently monitor the assembly operation for all three individual grippers. This work presents a strategy to use visual information from only one gripper set for all the necessary alignment and positioning processes. Through proper system calibration and the alignment algorithms developed, grippers that were not visually monitored could also perform the assembly operations. When using visual images from a single vision camera for 3D positioning, the extra dimension between the 2D image and 3D workspace results in errors in position evaluation. Hence, a novel approach is presented to utilize image reflection of the micropart for online evaluation of the Jacobian matrix. The relative 3D position between the slot and micropart was evaluated with high precision. The developed algorithms were integrated onto the micromanipulation system. Automated parallel microassemblies were conducted successfully.

The introduction of microassembly technologies has opened up new venues for the fabrication of sophisticated, three-dimensional Microelectromechanical System (MEMS) devices. This thesis presents the development of a robotic micromanipulation system and its controller algorithms for conventional pick-and-place microassembly processes. This work incorporated the approach of parallel assembly and automation to improve overall productivity and reduce operating costs of the process. A parallel set of three microgrippers was designed and implemented for the grasping and assembly of three microparts simultaneously. The complete microassembly process was automated through a vision-based control approach. Visual images from two vision systems were adopted for precise position evaluation and alignment. Precise alignment between the micropart and microgripper is critical to the microassembly process. Due to the limited field of view of the vision systems, the micropart could displace away from the microscope field of view during the re-orientation process. In this work, a tracking algorithm was developed to constrain the micropart within the camera view. The unwanted translational motions of the micropart were estimated. The algorithm then continuously manipulated and repositioned the micropart for the vision-based assembly. In addition, the limited fields of view of the vision systems are not sufficient to concurrently monitor the assembly operation for all three individual grippers. This work presents a strategy to use visual information from only one gripper set for all the necessary alignment and positioning processes. Through proper system calibration and the alignment algorithms developed, grippers that were not visually monitored could also perform the assembly operations. When using visual images from a single vision camera for 3D positioning, the extra dimension between the 2D image and 3D workspace results in errors in position evaluation. Hence, a novel approach is presented to utilize image reflection of the micropart for online evaluation of the Jacobian matrix. The relative 3D position between the slot and micropart was evaluated with high precision. The developed algorithms were integrated onto the micromanipulation system. Automated parallel microassemblies were conducted successfully.

EN: There is an industrial need for new technologies that can manipulate objects in the micrometric scale (1-1000 μm). In this thesis, an original non-contact actuation technique for the manipulation of microscale objects is proposed. The proposal is to use laser-induced thermocapillary convective flows to manipulate particles at the fluid/gas interface. These flows are generated when a surface tension stress is generated at the fluid/gas interface due to a thermal gradient. Laser heating is used because the generated thermal gradients produce fast, localized flows that improve the actuation performance. The particles are manipulated at the interface because the flow generated there is the fastest in the entire fluid. To ensure the precise positioning of a particle, closed-loop controllers are implemented in the system which are designed based on models proposed for the system. Experimental tests are performed that show that positioning precision can be ensured. In addition, the interaction forces between particles have been studied which is a preliminary step towards parallel manipulation. To counteract those forces during the manipulation, a different control strategy has been proposed, implemented and tested using simulations. Overall, the results obtained are comparable to the ones obtained with the other techniques. Therefore, the proposed technique can be considered as an attractive alternative that offers different advantages and disadvantages. FR: Il existe un besoin industriel croissant de nouvelles technologies capables de manipuler des objets à l’échelle micrométrique (1-1000 μm). Dans cette thèse, une technique originale d’actionnement sans contact pour la manipulation d’objets à l’échelle micrométrique est proposée. Elle est basée sur les écoulements thermocapillaires convectifs induits par un laser pour manipuler des particules à l’interface fluide/gaz. Le laser chauffe localement la surface de l’eau, ce qui induit un gradient de tension de surface. Ce gradient génère un écoulement fluidique. Ces écoulements sont rapides et localisés, ce qui confère des performances intéressantes à cette technique d’actionnement. Les particules sont manipulées à l’interface fluide/gaz, où l’écoulement généré est le plus rapide.Pour assurer le positionnement précis d’une particule, des contrôleurs en boucle fermée sont implémentés dans le système. Ils sont basés sur les modèles développés dans cette thèse. Des essais expérimentaux montrent que le positionnement précis de particules peut être assuré. De plus, les forces d’interaction entre des particules placées à l’interface ont été étudiées, et une stratégie de contrôle a été proposée, en vue de la manipulation en parallèle de plusieurs particules. Tant les études analytiques et les simulations numériques que les tests expérimentaux soulignent l’intérêt des écoulements thermocapillaires convectifs pour la manipulation contrôlée d’objets micrométriques. Cette technique est donc une alternative prometteuse aux approches classiques d’actionnement sans contact. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

This diploma thesis deals with optimization of analysis process and measuring antibiotics induced changes in E. coli cells via Raman spectroscopy, LTRS and microfluidic systems. Optical micromanipulation by a laser beam allows noncontact and noninvasive manipulation of objects on scale 10^-5–10^-8 m, for example bacterial cells. Microfluidic device consists of microchannels and microchambers in transparent polymer and it is used for isolation, observation and cultivation of bacterial cells. Combination of these methods gives an effective tool for observation, manipulation and analysis of microorganisms. E. coli is a microorganism potentially pathogenic for humans and faster detection of its sensitivity to antibiotic treatment would make the whole process of diagnostics and treatment easier. We performed laser tweezer-Raman spectroscopy and conventional Raman spectroscopy of bacterial cells and cells under antibiotic stress and collected Raman spectra and characteristic areas were compared with literature to establish the reliability and usefulness of this method.