If you are interested to work in our group don’t hesitate to contact us (sandrine.leveque-fort (at) u-psud.fr)<\/p>\n
L3 and M1 internship available contact us for details on the topics ( summer 2022)<\/p>\n
M2 internship + PhD Opportunity for student with background in optics\/ Sujet de stage M2 pour \u00e9tudiant en physique\/optique avec poursuite en th\u00e8se possible :<\/p>\n
Development of a new detection approach in super-resolution fluorescence microscopy for biology (starting in 2022) :<\/p>\n
The diffraction limit that has long restricted the observation of biological systems is now being overcome, thanks to the recent development of approaches combining optics and photophysics of fluorescent emitters. In particular, the development of single molecule localization microscopy approaches (dSTORM\/PALM) allows the lateral localization of fluorescent molecules with a precision of the order of 5-10 nm. One of the main challengesis to extract axial information with a level of resolution close to the lateral resolution and for molecules located deep in complex samples. The Nanobio team at ISMO is thus developing different strategies to improve 3D imaging for different biological applications (Nature Photonics 2015, ACS Nano 2017, Nature comm 2019, Nature comm 2021, Nature Photonics 2021).
\nIn particular, we have developed in collaboration with the Institut Langevin a new approach based on the introduction of a temporally modulated excitation that allows to exceed current techniques by up to a factor of 5 and to preserve an identical axial resolution down to several tens of microns in depth in the sample. This technique, called Modloc, is based in particular on an original optical detection strategy protected by a patent, which permits to extract the position of the molecules thanks to the phase of their modulated fluorescence emission.
\nWithin the framework of this internship, we wish to push the limits of this new approach by rethinking the optical configuration of the detection module in order to accelerate the acquisition, improve the resolution and the axial observation range. Following simulation (CRLB), an axial precision below 4 nm could be achieved, further unlocking new biological applications. Extension of the axial capture range will be tested by introducing a phase mask. Furthermore, a key point for biological applications is the capability to identify different fluorophores, each revealing the organization of a different protein, in order to study the co-localization of proteins and understand their interactions. Thus the development of this new module will also include the possibility of detecting spectrally close fluorophores thanks to ratiometric analysis. After a phase of familiarization with localization microscopy and the structured excitation module, the new optical module for fluorescence detection will be set up. After a validation phase on calibration samples, biological samples will be observed with our biologist collaborators. This internship will be carried out in the framework of a collaboration with Institut Langevin and IPSIT for biological application.<\/p>\n
M2 internship + PhD Opportunity for student with background in optics\/ Sujet de stage M2 pour \u00e9tudiant en physique\/optique avec poursuite en th\u00e8se possible (starting in 2022):
\nin collaboration with abbelight
\nMicroscopie de fluorescence supercritique pour l\u2019imagerie 3D super-r\u00e9solue.
\nR\u00e9sum\u00e9 \/ summary : Les techniques de microscopie super-r\u00e9solue permettent d\u2019observer les \u00e9chantillons biologiques avec une r\u00e9solution bien au-del\u00e0 de la limite de diffraction, ouvrant ainsi des pans entiers d\u2019application. En particulier les approches de localisation de mol\u00e9cules uniques repose sur la possibilit\u00e9 de contraindre les mol\u00e9cules \u00e0 \u00e9mettre de fa\u00e7on d\u00e9cal\u00e9es dans le temps et l\u2019espace, et renseigne sur la position lat\u00e9rale de la mol\u00e9cule avec une pr\u00e9cision de l\u2019ordre de 10 nm. L\u2019obtention de l\u2019information suivant l\u2019axe optique requiert l\u2019utilisation d\u2019une approche compl\u00e9mentaire afin de pouvoir obtenir des images super-r\u00e9solues en 3D, et constitue encore actuellement un v\u00e9ritable defi. L\u2019\u00e9quipe Nanobio de l\u2019ISMO d\u00e9veloppe ainsi diff\u00e9rentes strat\u00e9gies pour am\u00e9liorer l\u2019imagerie en 3D (Nature Photonics 2015, ACS Nano 2017, Nature comm 2019, Nature comm 2021, Nature Photonics 2021). En particulier l\u2019une de ces approches repose sur l\u2019utilisation des propri\u00e9t\u00e9s d\u2019\u00e9mission des mol\u00e9cules fluorescentes : \u00e0 proximit\u00e9 de la lamelle de verre, le champ proche des mol\u00e9cules devient propagatif et apparait au d\u00e9l\u00e0 de l\u2019angle critique, d\u2019o\u00f9 son nom de lumi\u00e8re supercritique. Comme cette \u00e9mission supercritique d\u00e9croit de fa\u00e7on exponentielle avec la distance \u00e0 la lamelle, elle permet d\u2019extraire la position de la mol\u00e9cule de fa\u00e7on absolue, ce qui pr\u00e9sente de nombreux avantages pour les applications biologiques. Nous avons mis en place diff\u00e9rentes modalit\u00e9s pour extraire specifiquement cette fluorescence supercritique intrins\u00e8quement porteuse de l\u2019information axiale, et qui a conduit \u00e0 la cr\u00e9ation de la spin-off abbelight.
\nDans le cadre de ce stage, nous proposons en collaboration avec abbelight de d\u00e9velopper une nouvelle impl\u00e9mentation de la d\u00e9tection de fluorescence supercritique afin de tendre vers une resolution isotrope gr\u00e2ce \u00e0 la mise en place d\u2019une nouvelle approche de filtrage. De plus, la compr\u00e9hension des syst\u00e8mes biologiques n\u00e9cessitant de pouvoir observer plusieurs prot\u00e9ines associ\u00e9es \u00e0 diff\u00e9rentes mol\u00e9cules fluorescentes, une s\u00e9paration spectrale sera \u00e9galement introduite. Le dispositif optique mis en place sera \u00e9valu\u00e9 dans un premier temps sur des objets de calibration et syst\u00e8mes biologiques mod\u00e8les, avant de l\u2019appliquer \u00e0 l\u2019observation des structures d\u2019adh\u00e9sion et de migration cellulaire.<\/p>\n","protected":false},"excerpt":{"rendered":"
If you are interested to work in our group don’t hesitate to contact us (sandrine.leveque-fort (at) u-psud.fr) L3 and M1 internship available contact us for details on the topics ( summer 2022) M2 internship + PhD Opportunity for student with background in optics\/ Sujet de stage M2 pour \u00e9tudiant en physique\/optique avec poursuite en th\u00e8se […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":[],"yoast_head":"\n\n\n\n\n\n\n\n\n\n\n\n\n\t\n