Tesi sul tema "Microscopie de fluorescence à feuille de lumière"
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Atlas, Yoann. "Mécanotransduction de microtumeurs vascularisées en culture 3D. Apport de la microscopie à feuille de lumière". Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS497.
Testo completoThe extracellular matrix (ECM), tumor secretome and tumor angiogenesis are highly dysregulated as a result of gene mutations and of the hypoxic microenvironment, promoting tumor progression. My PhD work aimed to investigate the impact of microenvironment on ccRCC tumor aggressiveness and its consequences on vascular morphogenesis, thanks to the simultaneous development of a digitally scanned laser fluorescent light-sheet microscope (DSLM) built in-house and of a 3-D vascularized microtumor model displaying perivascular coverage and controlled ECM physical properties.I first characterized a 3-D in vitro model of perivascular recruitment of mesemchymal stem cells, providing an essential tool for elucidating interactions of perivascular and tumor cells with endothelial cells.I then analyzed the ECM remodeling associated with angiogenesis, and developed a biomimetic strategy with LOXL2 for cross-linking collagen I hydrogels in order to modulate ECM physical properties and to enhance capillary formation. Once development of these tools achieved, I demonstrated the synergistic impact of EMT, paracrine factors and physical properties of the microenvironment on tumor invasion of ccRCC cell line. Vascularized tumor spheroids allowed observation of direct interactions between tumor cells and endothelial cells through a process reminiscent of vascular co-option by tumor cells.Altogether these data further understanding on the role of the microenvironment in modulation of angiogenesis and in tumor invasiveness driven by VHL mutation
Mercier, Mathias. "Optique adaptative basée sur la mesure de front d’onde en source étendue pour la microscopie à feuille de lumière à haute résolution". Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS670.
Testo completoThe use of light-sheet fluorescence microscopy (LSFM) is a technique of choice for high spatial and temporal resolution 3D imaging of living samples. However, at depth in biological samples, optical aberrations induced by tissue refractive index inhomogeneity result in a significant loss of contrast and spatial resolution. To compensate for these aberrations and thus recover an image limited only by diffraction, we have combined an LSFM microscope with adaptive optics (AO) based on direct wavefront measurement with an extended-source Shack-Hartmann wavefront sensor(ESSH). This original approach leads to efficient and rapid wavefront correction, as it does not require the iterative algorithms used in sensorless AO configurations, and to easier implementation compatible with the study of living samples, as it does not require the invasive insertion of fluorescent beads or the complex and costly use of a pulsed laser to generate a guide star. However, performance in such an instrument is subject to the geometry of the excitation: the ESSH sensor performs a wavefront measurement averaged over the fluorescent volume imaged by the microlenses of which it is composed, and fixed by the thickness of the light-sheet. To optimize wavefront measurement and correction, and consequently the gain provided by the AO, it is necessary to minimize the thickness of the light sheet at illumination over the entire field of view of the ESSH sensor, ideally to make it equal to the depth of field of the collection objective. This is made possible by a recently developed LSFM configuration, axially swept light-sheet microscopy, which achieves a light-sheet thickness of less than 1 micrometer while maintaining a field of view of 500 x 500 µm². I present the implementation of this high-spatial-resolution light-sheet microscope, combined with an adaptive optics loop based on extended-source wavefront measurement, its characterization and performance, as well as in-depth imaging results on live zebrafish larvae
Gasecka, Alicja. "Polarimetric multiphoton fluorescence microscopy in molecular and biological media". Aix-Marseille 3, 2010. http://www.theses.fr/2010AIX30068.
Testo completoLight-matter interaction in molecular and bio-molecular media can lead to complex processes where optical fields polarizations couple to an assembly of molecular transition dipoles. The manipulation of the optical fields polarization in fluorescence microscopy can in particular give access to fine changes occurring in molecular arrangements. In this PhD thesis we report a method based on a tuneable excitation polarization state complemented by a polarized read-out, applied to polarization-resolved multiphoton fluorescence microscopy. Two-photon fluorescence polarimetry allows to retrieve a quantitative information on the static molecular distribution shape and orientation in different environments such as model lipid membranes, cell membranes, and molecular inclusion compounds that can be strongly heterogeneous. Three-photon fluorescence polarimetry has been furthermore applied in bio-molecular media in order to provide a diagnostics for crystallinity in protein crystals with high sensitivity to their structure and symmetry. The experimental implementation of polarimetric multi-photon microscopy requires to quantify possible polarization distortions originating from the experimental set-up or sample itself, which are thoroughly analyzed
Courvoisier, Céline. "Etude d'un continuum de lumière en régime femtoseconde. Applications au domaine biologique : microscopies et spectroscopie en temps résolu". Phd thesis, Besançon, 2006. http://www.theses.fr/2006BESA2027.
Testo completoJorand, Raphaël. "Amélioration des voies de détection et d'illumination d'un microscope SPIM pour l'imagerie 3D des sphéroïdes". Toulouse 3, 2013. http://thesesups.ups-tlse.fr/2267/.
Testo completoThe aim of our thesis work was to improve spheroid imaging quality focusing on the study and development of both illumination and detection path of the SPIM. This work shows the possibility to improve deep image quality by using an adaptive optics loop consisting of a deformable mirror and a Shack Hartmann wavefront sensor. In order to work, the loop needs fluorescent source points known as "guide stars", which was also a part of our study. Furthermore, we have also compared different light sheet illumination modalities (1 photon versus 2 photons, Gaussian beam or Bessel beam. . . ) as well as developing an automated and standardized image analysis procedure
Negash, Awoke. "Superresolution fluorescence microscopy with structured illumination". Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/461679.
Testo completoLa microscopie de fluorescence optique est l’un des outils les plus puissants pour étudier les structures cellulaires et moléculaires au niveau subcellulaire. La résolution d’une image de microscope conventionnel à fluorescence est limitée par la diffraction, ce qui permet d’obtenir une résolution spatiale latérale de 200nm et axiale de 500nm. Récemment, de nombreuses techniques de microscopie de fluorescence de super-résolution ont été développées pour permettre d’observer de nombreuses structures biologiques au-delà de la limite de diffraction. La microscopie d’illumination structurée (SIM) est l’une de ces technologies. Le principe de la SIM est basé sur l’utilisation d’une grille de lumière harmonique qui permet de translater les hautes fréquences spatiales de l’échantillon vers la région d’observation du microscope. L’amélioration de la résolution de cette technologie de microscopie dépend fortement de la technique de reconstruction, qui rétablit les hautes fréquences spatiales de l’échantillon dans leur position d’origine. Les méthodes classiques de reconstruction SIM nécessitent une connaissance parfaite de l’illumination de l’échantillon. Cependant, l’implémentation d’un contrôle parfait de l’illumination harmonique sur le plan de l’échantillon n’est pas facile expérimentalement et il présente un grand défi. L’hypothèse de la connaissance parfaite de l’intensité de la lumière illuminant l’échantillon en SIM peut donc introduire des artefacts sur l’image reconstruite de l’échantillon, à cause des erreurs d’alignement de la grille qui peuvent se présenter lors de l’acquisition expérimentale. Afin de surmonter ce défi, nous avons développé dans cette thèse des stratégies de reconstruction «aveugle» qui sont indépendantes de d’illumination. À l’aide de ces stratégies de reconstruction dites «blind-SIM», nous avons étendu la SIM harmonique pour l’appliquer aux cas de «SIM-speckle» qui utilisent des illuminations aléatoires et inconnues qui contrairement à l’illumination harmonique, ne nécessitent pas de controle. Comme il est utile de récupérer des informations sur l’illumination en SIM harmonique, nous avons développé une reconstruction blind-SIM tridimensionnel et filtrée qui confine l’estimation itérative des illuminations au voisinage des pics dans l’espace de Fourier, en utilisant des masques de filtre de Fourier soigneusement conçus. En utilisant des techniques de reconstruction blind-SIM, une résolution latérale d’environ 100 nm et une résolution axiale d’environ 200 nm sont obtenues, à la fois en SIM harmonique et en SIM speckle. En outre, pour réduire le problème de focalisation dans les images de champ large, une technique de calcul simple qui repose sur la reconstruction bidimensionnel de données à partir de PSF tridimensionnel est développée. En outre, afin de combiner à la fois les fonctionnalités de la SIM et de la microscopie á nappe de lumière, en tant que preuve de concept, nous avons développé une configuration de microscope simple qui produit une nappe de lumière structurée
Bergamaschi, Antoine. "Développements méthodologiques et logiciels pour l’imagerie X multimodale par balayage sur la ligne de lumière Nanoscopium". Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS054/document.
Testo completoThe subject of this thesis is the methodological and software development of tools for processing very large multimodal and tomographic datasets produced on Nanoscopium beamline in the SOLEIL synchrotron. Scanning hard X-ray imaging allows simultaneous acquisition of multimodal information, i.e. of images in which each pixel contains several types of data. Combining these scanning techniques with the FLYSCAN infrastructure, developed for fast data acquisition at Synchrotron SOLEIL, permits to perform multimodal tomographic imaging and tomographic reconstruction during routine user experiments. A main challenge of such imaging techniques is the online processing of the important amount of generated multimodal data. The main outcome of this thesis work is the MMX-I software which is dedicated to processing large 2D/3D multimodal dataset. This software includes an original algorithm for continuous reading of large data volumes, several reduction functions, two phase reconstruction algorithms (integration in Fourier space and iterative technics) and tomographic reconstruction technics (filtered back projection and iterative technics). Every implemented method as well as application allowing to validate the new developments and few evolution perspectives are presented in this thesis manuscript
Morgado, Brajones Javier. "OPTO-MECA-SPIM : imagerie dynamique et interactive de phénomènes mécanobiologiques dans les tissus". Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30252.
Testo completoIn recent years, tissue mimics (TMs) such as microtissues, spheroids, and organoid cultures have become increasingly important in life-science research, as they provide a physiologically relevant environment for cell growth, tissue morphogenesis, and stem cell differentiation. Selective Plane Illumination Microscopy (SPIM) is one of the most prominent microscopy modalities for three-dimensional tissue imaging, and a sine qua non tool to understand cell biology in TMs. However, while SPIM is regarded as a very powerful tool for TM imaging, optical microscopy suffers from certain limitations when imaging 3D samples. Indeed, scattering, absorption and optical aberrations limit the depth at which useful imaging can be done, typically no more than 100 µm. Adaptive Optics (AO) is a technique capable of improving image quality at depth by correcting the optical aberrations introduced by the sample which is seeing increasing use in fluorescence microscopes. For this thesis, I have incorporated a wavefront sensor AO scheme to SPIM, able to correct aberrations in optically thick TMs such as multi-cellular tumor spheroids (MCTS). Due to the low amount of light produced by non-linear guide stars such as the one used in our system, a custom high-sensitivity Shack-Hartmann wavefront sensor (SHWFS) was developed for our needs. In this work, I characterize the performance of this SHWFS and the ability of our system to correct aberration in various conditions, including inside TMs. I show unprecedented image quality improvements for in-depth imaging of MCTS, in regard of high-frequency detail and resolution. This allowed us to identify biologically relevant features at depths inaccessible to conventional SPIM. Up-converting nanoparticles (UCNP) are rare-earth based particles that are able to undergo photon up-conversion when illuminated, emitting light of a shorter wavelength than that of the illumination. Guide stars made from UCNP are especially attractive due to the possibility of them being excited in the near-infrared while emitting visible light, reducing photodamage produced by the illumination light. The viability of using UCNP as guide stars in biological samples in explored in this thesis
Monti, Fabrice. "Microrhéologie de suspensions colloïdales non ergodiques : Relaxations locales, dynamiques lentes et vieillissement". Phd thesis, Paris 6, 2010. http://pastel.archives-ouvertes.fr/pastel-00560061.
Testo completoGiehl, Zanetti Betina. "Evaluation du potentiel d'utilisation d'un polyuréthane obtenu à partir d'un polyol d'origine natuel comme matériel polymérique pour la micro et nano encapsulation d'agents actifs". Bordeaux 1, 2006. http://www.theses.fr/2006BOR13153.
Testo completoEpron, Daniel. "Effets des déficits hydriques et des forts éclairements sur la photosynthèse de jeunes semis de chênes en conditions contrôlées et de chênes adultes en conditions naturelles". Nancy 1, 1993. http://www.theses.fr/1993NAN10010.
Testo completoLabouesse, Simon. "Imagerie à éclairements structurés inconnus". Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0335.
Testo completoStructured illumination microscopy (SIM) allow theoretically to double the super-resolution of a standard optical microscope. However, to reach this theoretical limit, SIM require a precise knowledge of the illuminations, making it costly and difficult to calibrate. The aim of this thesis is to simplify the use of SIM by using a blind approach who allow the use of random illuminations to reconstruct a super-resolved image of the object. This strategy theoretically allow the super-resolution, while maintaining a low cost instrumentation. During those three years of thesis, we have studied theoretically and algorithmically the performances and the limitations of a joint estimator of the objet and the illuminations (joint Blind-SIM estimator). A mathematically equivalent reformulation of the joint problem was proposed allowing us to study the super-resolution origin and to propose a fast and parallelizable new approach. An empirical study has highlighted the impact of parsimony and of the frequency content of the illuminations on the reached super-resolution level. Because the joint estimator is asymptotically not consistent, we also studied a contrast criterion for our problem (typically a marginal likelihood), here only the object of interest is estimated. We have mathematically studied the super-resolution capacity of this kind of estimators. Finally, real data using random illuminations where acquired and we have observed a super-resolution effect using our algorithms on multiples real objects of different kind, 2 or 3D, fix or mobile, biological or not, like beads, podosomes, actines
Habib, Lamice. "Étude des propriétés membranaires des vésicules lipidiques incorporant des triterpènes oxygénés bioactifs d'origine végétale : application à la cucurbitacine E et à l'érythrodiol". Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10022/document.
Testo completoCucurbitacin E and erythrodiol are natural oxygenated triterpenes having respectively, a tetra and pentacyclic skeleton. They are known for their numerous biological properties. In this thesis, we studied their interaction with the membranes of lipid vesicles to better understand their pharmacodynamics. We have prepared liposomes in the absence and presence of cucurbitacin E and erythrodiol using the reverse phase evaporation technique followed by extrusion, the hydration of lipid film and the ethanol injection techniques. The physicochemical characteristics of lipid vesicles incorporating or not the triterpenic molecules were investigated by appropriate techniques. The determination of cucurbitacin E and erythrodiol in the vesicles by high performance liquid chromatography showed high incorporation efficiencies of both triterpenes. Size measurements obtained by dynamic light scattering showed that liposomes incorporating triterpenes were smaller than empty liposomes. The images obtained by transmission electron microscopy confirmed the formation of spherical vesicles. Measurements of vesicles dimensions by atomic force microscopy (AFM) demonstrated that liposomes incorporating cucurbitacin E were higher and more resistant to the force exerted by the AFM tip than the blank liposomes. Liposomes incorporating erythrodiol were more fragile and tend to break up into lipid bilayers on the mica surface. Results obtained by differential scanning calorimetry suggested that cucurbitacin E is localized at the polar-apolar interface of the liposomal membrane while erythrodiol is inserted between the acyl chains of the phospholipids leading to the formation of heterogeneous lipid domains. The release kinetics of the sulforhodamin B encapsulated into the aqueous phase and measured by fluorescence spectroscopy revealed that the liposomal membrane becomes in the presence of cucurbitacin E, more permeable to this probe. The overall results suggest that cucurbitacin E and erythrodiol affect differently
Gug, Sylvestre. "Synthèse et caractérisation de groupements protecteurs photolabiles à deux photons : Applications biologiques". Strasbourg 1, 2008. http://www.theses.fr/2008STR13200.
Testo completoThe synthesis and the characterization of new two-photon photolabile protecting group is described in this work. Twelve molecules (cages) have been developed, following an innovative molecular engineering method. The photophysical and photochemical properties were fully characterized. These different photolabile protecting group coupled to glutamate has then been tested on neuronal culture and showed a very high efficiency
Balakrishnan, Nair Gireeshkumar. "Diffusion de particules dans des gels de protéines et aux interfaces". Phd thesis, Université du Maine, 2012. http://tel.archives-ouvertes.fr/tel-00710630.
Testo completoBalakrishnan, Nair Gireeshkumar. "Particle diffusion in protein gels and at interfaces". Thesis, Le Mans, 2012. http://www.theses.fr/2012LEMA1002/document.
Testo completoThe objective of the thesis was to investigate the mobility of tracer particles in complex media byConfocal Laser Scanning Microscopy (CLSM) combined with multiple particle tracking (MPT)and fluorescence recovery after photobleaching (FRAP).First, we investigated the diffusion of tracer particles in gels formed by globular proteins. Gelswith a variety of structures were prepared by varying the protein and salt concentrations. Thestructure was characterized by analysis of the CLSM images in terms of the pair correlationfunction. The mobility of particles with a broad range of sizes (2nm - 1μm) was investigatedboth in homogeneous and heterogeneous gels and related to the gel structure.Second, we studied water-in-water-emulsions prepared by mixing aqueous solutions of PEO anddextran. It is shown that when colloidal particles are added they become trapped at the waterwaterinterface because they reduce the interfacial tension. The structure and the displacement ofthe particles at the interface were determined using CLSM combined with MPT
Colombani, Jean. "Physique des liquides aux interfaces". Habilitation à diriger des recherches, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00588841.
Testo completoGerard, Francine. "Caractérisations biophysiques et structurales du complexe de réplication des Rhabdoviridae". Phd thesis, 2008. http://tel.archives-ouvertes.fr/tel-00343710.
Testo completoL'analyse biophysique montre que P RV & VSV existent sous forme de dimère allongé en solution. L'analyse bioinformatique a révélé une organisation modulaire, confirmé par des études biochimiques et biophysiques de mutants de P RV. La structure du domaine C-terminal de P VSV a été résolue par RMN et montre une homologie celle du C-ter de P RV. La caractérisation de l'interaction entre P et les anneaux N-ARN a révélé l'existence de deux types de complexes N-ARN-P (contenant un et 2 dimères de P par anneau). L'étude par ME des complexes nucléocapsides-P a permis de mettre en évidence un changement de conformation important.
Pour devenir accessible à L, l'ARN viral doit se dissocier localement de N. L'interaction N-ARN-P représente potentiellement une nouvelle cible pour le développement d'antiviraux.