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Статті в журналах з теми "Microscope multiphotonique"
Treacy, P., I. Pavlova, U. Falagario, R. Brody, J. Epstein, J. Cordero Bravo, F. Barthe, P. Wiklund, A. Tewari, and M. Durand. "Mesure du collagène au sein d’un tissu cancéreux prostatique à l’aide du microscope multiphotonique : résultats préliminaires." Progrès en Urologie 29, no. 13 (November 2019): 745–46. http://dx.doi.org/10.1016/j.purol.2019.08.218.
Повний текст джерелаHernest, Monica, Ana-Maria Pena, Mathias Strupler, Emmanuel Beaurepaire, Jean-Louis Martin, Marie-Claire Schanne-Klein, and Pierre-Louis Tharaux. "Nouvelle approche des fibroses par microscopie multiphotonique avec génération de second harmonique." médecine/sciences 22, no. 10 (October 2006): 820–21. http://dx.doi.org/10.1051/medsci/20062210820.
Повний текст джерелаDurand, M., A. Aggarwal, B. Robinson, P. Sooriakumaran, A. Srivastava, W. Zipfel, J. Amiel, and A. Tewari. "La microscopie multiphotonique in vivo en temps reel : une imagerie prometteuse pour l’analyse histologique virutelle des tissus frais sans biopsie." Progrès en Urologie 23, no. 13 (November 2013): 1114. http://dx.doi.org/10.1016/j.purol.2013.08.221.
Повний текст джерелаДисертації з теми "Microscope multiphotonique"
Guillemant, Marie. "Development of a three-photon microscope for awake and behaving non-human primates." Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPASL025.
Повний текст джерелаMulti-photon microscopy has become a standard technique to study the structural and functional activity in mice but it faces obstacles to be applied in larger animals. It would be particularly advantageous to be able to apply it to macaque monkeys, as they are the animal model of choice to understand the neural mechanisms of high-level cognitive functions such as selective attention, working memory and consciousness. One of the main limiting factors for imaging in larger animals is the dura mater. This tough and opaque layer of tissue protects the brain but is so thick in larger animals that it obstructs imaging. It is therefore commonly removed but this leads to a highly invasive and unstable preparation. The main aim of the current work is to investigate the possibility to record functional activity from the cortex of the rhesus macaque monkey through the natural dura.A multi-photon microscopy setup has been designed with a two-photon and a three-photon microscopy optical paths to record from awake macaque monkeys. The repetition rate of the laser is 2MHz which allows a maximum imaging depth inside the cortex of 520µm at 960nm and 715µm at 1300nm with an additional 120µm-thick layer of dura mater at the surface. Resonance-galvo scanning is used to allow a maximal frame rate of 15.6Hz at a field of view of 620x630µm². In addition to the setup, surgical implants have been developed for long-term and awake imaging.Using an ex vivo study of dura mater from a macaque monkey, the induced optical aberrations are studied by measuring the decrease in spatial resolution of the setup for a varying thickness of dura mater. This reveals that it has no significant impact on the spatial resolution for a thickness up to 150µm at 1300nm. The effective attenuation length of the dura mater is estimated to be 56.5±10.1µm at 960nm and 80.7±5.3µm at 1300nm. These measurements are used to model the maximum imaging depth that can be reached according to the repetition rate of the laser and the thickness of the dura.This model is adjusted and validated using in vivo data from two non-human primates. The effective attenuation length of the natural dura mater and of a regrowth of tissue following a durectomy (called a 'neomembrane') are investigated. Functional recordings have been performed in mice and preprocessed using Suite2P. Viral injection parameters have been tested in three macaque monkeys and we have so far recorded the in vivo structural and functional activity of neurons in one. Finally, the comparison between the use of two- and three-photon microscopy to study non-human primates is discussed. In conclusion, we have set up and optimized a multi-photon microscope for long-term awake imaging of the cortex of non-human primates and shown that it was possible to record down to over 700µm into the cortex (which corresponds to the layers L2/L3) while imaging through the natural dura mater or a neomembrane
Thériault, Gabrielle. "Développement d'un microscope à grande profondeur de champ pour l'imagerie fonctionnelle de neurones dans des échantillons épais." Doctoral thesis, Université Laval, 2015. http://hdl.handle.net/20.500.11794/25740.
Повний текст джерелаOne of the greatest challenges of modern neuroscience that will lead to a better understanding and earlier diagnostics of brain sickness is to decipher the details of neuronal interactions in the living brain. To achieve this goal, we must be capable of observing populations of living cells in their original matrix with a good resolution, both spatial and temporal. Two-photon microscopy offers the right tools for this since it presents with a spatial resolution in the order of the micron. Unfortunately, this very good three-dimensional resolution lowers the temporal resolution because the optical sectioning caused by the microscope's small depth of field forces us to scan thick samples repeatedly when acquiring data from a large volume. In this doctoral project, we have designed, built and characterized a two-photon microscope with an extended depth of field with the goal of simplifying the functional imaging of neurons in thick samples. To increase the laser scanning microscope's depth of field, we shaped the laser beam entering the optical system in such a way that a needle of light is generated inside the sample instead of a spot. We modify the laser beam with an axicon, a cone-shaped lens that transforms a gaussian beam into a quasi non-diffractive beam called Bessel-Gauss beam. The excitation beam therefore maintains the same transverse resolution at different depths inside the sample, eliminating the need for many scans in order to probe the entire volume of interest. In this thesis, we demonstrate that the extended depth of field microscope effectively works as we designed it, and we use it to image calcium dynamics in a three-dimensional network of live neurons. We also present the different advantages of our system in comparison with standard two-photon microscopy.
Canonge, Rafael. "Imagerie moléculaire 3D quantitative des tissus en utilisant la microscopie Raman cohérente sans marquage." Thesis, Ecole centrale de Marseille, 2017. http://www.theses.fr/2017ECDM0010/document.
Повний текст джерелаThis thesis focuses on multiphotonic microscopy techniques development and use in order to image human biological samples. A multiphotonic imaging setup using label-free nonlinear contrasts mechanisms such as two-photons fluorescence, second harmonic generation, or stimulated Raman effect (CARS or SRS) has been designed and developped during this PhD, and I present the experimental work in two main research topics.In a first part, we compare label-free 3D imaging with classic histological imaging using colorimetric labels in human digestive system. We show that multiphotonic technics allow to reconstruct the organization and discern the molecular compounds inside the tissues, in order to get a caratérization of the cancerous tumors developpement.The second part is related to the application of our multimodal setup to the quantitative study of real active molecular compounds real time penetration into in vivo human skin. We show that multiphotonic microscopy make possible to mesure active molecules in depth 3D concentration in the skin in order to understand transcutaneous diffusion mechanisms in cosmetic and pharmacological applications
Strupler, Mathias. "Imagerie du collagène par microscopie multiphotonique." Phd thesis, Ecole Polytechnique X, 2008. http://pastel.archives-ouvertes.fr/pastel-00004540.
Повний текст джерелаLeray, Aymeric. "Microscopie multiphotonique appliquée à la biologie." Rennes 1, 2005. http://www.theses.fr/2005REN1S156.
Повний текст джерелаSlimani, Amel. "Photonic approach for the study of dental hard tissues and carious lesion detection." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTT125.
Повний текст джерелаPhotonic properties of dental hard tissues allowed us to proceed to in vitro analysis of enamel and dentin on a molecular level. Confocal Raman microscopy has been used to produce a mapping of collagen cross-link and crystallinity of human dentin–enamel junction (DEJ) with a spatial resolution not achieved up to now. The method is a non-invasive, label-free and a high spatial resolution imaging technique. This chemical analysis of DEJ led us to redefine a wider width of this transition zone and advance our understanding of dental histology. A study on the intrinsic fluorescence changes of sound and carious tissues using conventional fluorescence microscopy suggests the involvement of protoporphyrin IX and pentosidine in the fluorescence red-shift observed in carious tissues. Multiphoton microscopy allowed to detect nonlinear optical signal changes during caries process using second harmonic generation (SHG) and two-photon excitation fluorescence (2PEF). Our studies led us to propose the ratio SHG/2PEF as valuable parameter to monitor caries lesion. Collectively, advances described in this thesis show the potential of photonic properties of enamel and dentin using Raman and multiphoton microcopies for molecular investigations on sound as much as on carious tissues. It opens new perspective in dental research and clinical applications
Guilbert, Thomas. "Microscopie multiphotonique de protéines fibrillaires : application à l’étude de la fibrose hépatique." Rennes 1, 2010. http://www.theses.fr/2010REN1S191.
Повний текст джерелаOptical imaging techniques based on nonlinear effects of photon-matter interactions, are increasingly applied in biology. Multiphoton microscopy provides an in-depth information at a micrometric scale in tissues, with low photo-toxicity. Moreover, the various sources of endogenous contrast in biological tissues allow to visualize, without any staining, the two photon excited fluorescence emission (TPEF), and second harmonic generation (SHG) of non-centrosymmetric molecules in non-centrosymmetric media, such as fibrillar proteins like collagen and myosin. These two endogenous contrasts enable a wide range of applications along with embryology, neuroscience or oncology. In this context, multiphoton microscopy appears as a promising tool for the study of fibrillar proteins present in biological tissues. In this document we first present the basis of multiphoton microscopy, the two contrasts involved in this imaging technique, and a tool based on the modulation of polarization of the exciting laser for the characterization of two fibrillar proteins, collagen and myosin. We also present a preliminary study of cattle skeletal muscle by multiphoton microscopy. In a second step, we use the specificity of SHG for imaging collagen to develop a method of scoring of fibrillar collagen deposits in human liver fibrosis. After an in-depth study of our collagen SHG scoring method, it is evaluated and compared to usual technics used to characterise fibrosis. This method which uses low NA lenses, could be extended to SHG endoscopes, when virtual biopsies will be possible
Thibon, Louis. "Méthodes d'augmentation de résolution en microscopie optique exploitant le modelage de faisceau laser et la déconvolution." Doctoral thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/34695.
Повний текст джерелаLaser scanning microscopy is limited in lateral resolution by the diffraction of light. Superresolution methods have been developed since the 90s to overcome this limitation. However, superresolution is generally achieved at the cost of a greater complexity (high power lasers, very long acquisition times, specic uorophores) and limitations on the observable samples. In some cases, such as Structured Illumination Microscopy (SIM) and Switching Laser Modes (SLAM), a more modest improvement in resolution is obtained with a reduced complexity and fewer limitations. We propose here methods which improve the resolution while minimizing the experimental constraints and keeping most of the advantages of classical microscopy. First, we show that we can improve by twenty percent the resolution of confocal microscopy by using Bessel-Gauss beams, and by having the right pinhole size (1 Airy Unit), compared to conventional Gaussian beam based confocal microscopy. The advantages of this strategy include simplicity of installation and use, linear polarization compatibility, possibility to combine it with other resolution enhancement and superresolution strategies. We demonstrate the resolution enhancement capabilities of Bessel-Gauss beams both theoretically and experimentally on nano-spheres and biological tissue samples with a resolution of 0.39. We achieved these resolutions without any residual artifacts coming from the Bessel-Gauss beam side lobes. We also show that the resolution enhancement of Bessel-Gauss beams leads to a better statistical colocalization analysis with fewer false positive results than when using Gaussian beams. We have also used Bessel-Gauss beams of different orders to further improve the resolution by combining them in SLAM microscopy achieving a resolution of 0.17 (90 nm with a wavelength of 532 nm). In a second step, we propose a method to improve the resolution of confocal microscopy by combining different laser modes and deconvolution. Two images of the same eld are acquired with the confocal microscope using different laser modes and are used as inputs to a deconvolution algorithm. The two laser modes have different Point Spread Functions and thus provide complementary information leading to an image with enhanced resolution compared to using a single confocal image as input to the same deconvolution algorithm. By changing the laser modes to Bessel-Gauss beams, we were able to improve the effciency of the deconvolution algorithm and to obtain images with a residual Point Spread Function having a width smaller than 100 nm. The proposed method requires only a few add-ons to the classic confocal or two photon microscopes. Finally, we propose a three dimensional tomography reconstruction method using Bessel-Gauss beams as projection tools in two-photon microscopy. While focussing Bessel-Gauss beams at an angle in two photon microscopy, we can obtain a series of projections that can be used for tomography reconstruction. The aim is to test the practicality of the methods allowing to reconstruct a volume while using fewer images than plane by plane acquisitions as in classic two-photon microscopy.
Nguyen, Anh Dung. "Amélioration de la résolution spatiale en microscopie multiphotonique par saturation de la fluorescence." Doctoral thesis, Universite Libre de Bruxelles, 2015. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/221923.
Повний текст джерела-----------------------Résumé-----------------------Depuis la prédiction de Maria Göppert-Mayer dans les années 30 de la possibilité pour une molécule fluorescente d'être excitée simultanément par plusieurs photons et, plus récemment, depuis le développement des lasers pulsés, la microscopie multiphotonique s'est peu à peu développée pour finalement s'imposer aujourd'hui comme un des outils d'observation par fluorescence les plus performants pour les études de tissus épais diffusants, ou encore pour l'observation in vivo d'animaux. Que ce soit pour des études neurologiques, physiologiques ou morphologiques, l'aspect non invasif et la limitation du volume excité au volume focal ont rendu cet outil de microscopie indispensable aux biologistes.Cependant, dans un monde où les études biologiques nécessitent toujours de meilleurs microscopes et où la résolution spatiale en particulier doit toujours être améliorée, il convient de proposer des techniques permettant d'obtenir une meilleure résolution dans les trois dimensions et d'aller au-delà de la limite de diffraction définie par Ernst Abbe il y a plus d'un siècle.Dans cette thèse, la technique de saturation de l'excitation de la fluorescence est adaptée à la microscopie multiphotonique. Cette méthode permet d'obtenir des images de superrésolution en modulant temporellement l'intensité laser d'excitation et en démodulant les harmoniques supérieures présentes dans le signal saturé de fluorescence. La démonstration de principe sur des microsphères fluorescentes a été réalisée montrant une amélioration de la résolution latérale et axiale. Alors que l'utilisation de la troisième harmonique produit déjà une meilleure résolution, ce travail de thèse montre qu'une amélioration supplémentaire peut être obtenue en utilisant une combinaison linéaire particulière des harmoniques démodulées.Au final, un quasi doublement de la résolution a pu être observé tant dans les directions latérales que dans la direction axiale. Cette amélioration correspond à l'amélioration prédite dans l'analyse théorique et mathématique réalisée également dans ce travail.De plus, le passage aux études in vitro a été réalisé avec succès en observant des microsphères fluorescentes incorporées dans des cellules HeLa. Des améliorations de la résolution latérale et axiale ont également été observées montrant que cette technique de superrésolution peut être appliquée à l'étude d'échantillons biologiques. Les forces et les faiblesses de cette méthode sont également analysées et détaillées afin de voir dans quel créneau d'études biologiques la technique de saturation de l'excitation de fluorescence pourrait se faire une place. A cette fin, ses caractéristiques sont comparées aux autres méthodes de superrésolution et de superlocalisation détaillées dans la première partie de ce travail.Il en resort que l'importante profondeur d'imagerie, l'aspect non invasif et la limitation du volume excité de la microscopie multiphotonique couplés à la simplicité d'implémentation et les relativement faibles puissances utilisées pour saturer l'excitation font de cette technique un excellent candidat pour des études in vivo dans des zones en profondeur dans des milieux diffusants comme la peau.
Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished
Quémener, Mireille. "Conception, fabrication et caractérisation d'un GRIN-axicon pour une application en microscopie multiphotonique." Master's thesis, Université Laval, 2021. http://hdl.handle.net/20.500.11794/68755.
Повний текст джерелаTechnological advances in microscopy have led to the creation of a wide variety of optical systems dedicated to the investigation of the dynamic behavior of cells in vivo. In neuroscience, the challenge lies in the observation of interactions between labeled neurons located at different depths in the tissue. In order to achieve this, it is necessary to scan the sample on several transverse planes to fully cover its volume. Since this procedure decreases the temporal resolution, it has been proposed to use an axicon to increase the depth of field of the microscope and reduce the number of scans to be performed. However, the axicon is di cult to manufacture and usually has defects on the tip of the cone, thus degrading the quality of the component. In order to replace the axicon by another optical component easier to manufacture, the use of a graded index lens coupled to a single lens (GRIN-axicon) was considered. Simulations have shown that the GRIN-axicon has the potential to produce a good quality Bessel beam. However, experimental tests have been very limited and it is necessary to further investigate the behaviour of this new component in the laboratory. The objective of this master's project is therefore to design, manufacture and characterize a GRIN-axicon for application in multiphoton microscopy. As a secondary objective, we wish to deepen the theory related to this new component.
Тези доповідей конференцій з теми "Microscope multiphotonique"
FERRANDON, Erwan, Mathis COURANT, Camélia POPESCU, Yann LAUNAY, Sophie ALAIN, and Claire LEFORT. "Un pipeline instrumental et computationnel pour visualiser des particules virales de SARS-CoV-2 en suspension." In Les journées de l'interdisciplinarité 2022. Limoges: Université de Limoges, 2022. http://dx.doi.org/10.25965/lji.684.
Повний текст джерелаLefort, Claire, Mathieu Chalvidal, Alexis Parenté, Véronique BLANQUET, Henri Massias, Laetitia MAGNOL, and Emilie Chouzenoux. "Imagerie 3D par microscopie multiphotonique appliquée aux sciences du vivant : la chaine instrumentale et computationnelle FAMOUS." In Les journées de l'interdisciplinarité 2022. Limoges: Université de Limoges, 2022. http://dx.doi.org/10.25965/lji.221.
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