Single molecule microscopy allows nanometer localization of the detected emitters and subtle probing of their spatio-temporal nano-environment including in living neuronal cells . I will present several single molecule strategies using different nano-emitters to probe complex and confined neuronal environments.
These include the development of a new probe delivery method in the live animal brain to perform the first single quantum dot tracking in acute brain slices  and an original strategy based on phase imaging aiming towards 3D single particle tracking and 3D super-resolution microscopy in thick cellular environments .
For deep tissue imaging, single walled carbon nanotubes, which bear optical resonances in the near infrared and nanoscale dimensions, are particularly promising . I will show that, long trajectories (>10 min) of nanotubes diffusing in the brain extracellular space can be recorded at the single nanotube level. Analysis their movements provides super-resolved maps of tissue structuration which can be modulated upon biochemical digestion of the brain extracellular matrix in live animals .
≠≠≠Laurent Cognet is Research Director at CNRS and PI in nano-biophotonics at University of Bordeaux, France. He is a member of the "Laboratoire Photonique Numérique et Nanosciences" (LP2N), a joint research unit of Institut d'Optique Graduate School, CNRS & University of Bordeaux. After a PhD in atom optics at Institut d'Optique-Orsay supervised by A. Aspect (Paris Sud University) L. Cognet performed among the first experiments about the detection and tracking of single fluorescent molecules in living cells as a postdoc in Th. Schmidt's group at Leiden University (NL). In 2000, he was tenured by CNRS as junior researcher at University of Bordeaux and he was promoted Research Director in 2009. In 2006, he spent a one-year sabbatical leave as a Fulbright scholar at Rice University (Houston, Texas) to work on carbon nanotube imaging. In 2011, he participated in the creation of LP2N where is deputy director and coordinates the Optics and Biology Research Initiative. His research interests include single molecule detection, super-resolution microscopy, single-wall carbon nanotube spectroscopy, and high-resolution bio-imaging applications with a particular focus in neuroscience.
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