Détails de la réservation
- Le : 5 October 2018
- De : 14 h 00
- à : 15 h 30
- Salle : Amphi Centre Broca Nouvelle - Aquitaine
Détails de l'évènement
Liangyi CHEN
Institute of Molecular Medicine, Peking University, Beijing 100871, China
"High spatiotemporal resolution fluorescence imaging of biological samples in vivo"
Résumé
Here we will present two pieces of high-resolution fluorescence microscopy methods we invented for live sample imaging. The first one is for in vivo imaging, which is a fast, high-resolution, miniaturized two-photon microscope (FHIRM-TPM). With a headpiece weighing 2.15 g and a new type of hollow-core photonic crystal fiber to deliver 920-nm femtosecond laser pulses, the FHIRM-TPM is capable of imaging commonly used biosensors at high spatiotemporal resolution (0.64 μm laterally and 3.35 μm axially, 40 Hz at 256 × 256 pixels). It compares favorably with benchtop two-photon microscopy and miniature wide-field fluorescence microscopy in the structural and functional imaging of Thy1-GFP- or GCaMP6f-labeled neurons. Further, we demonstrate its unique application and robustness with hour-long recording of neuronal activities down to the level of spines in mice engaging in social interaction.
The second method is for live cell long-term super-resolution (SR) imaging. We have developed a deconvolution algorithm for structured illumination microscopy based on Hessian matrixes (Hessian-SIM). It uses the continuity of biological structures in multiple dimensions as a priori knowledge to guide image reconstruction and attains artifact-minimized SR images with less than 10% of the photon dose used by conventional SIM while substantially outperforming current algorithms at low signal intensities. Hessian-SIM enables rapid imaging of moving vesicles or loops in the endoplasmic reticulum without motion artifacts and with a spatiotemporal resolution of 88 nm and 188 Hz. Its high sensitivity allows the use of sub-millisecond excitation pulses followed by dark recovery times to reduce photobleaching of fluorescent proteins, enabling hour-long time-lapse SR imaging in live cells.
Invitant : Daniel Choquet, Team Leader: Dynamic organization & Function of synapses / Directeur de l'IINS
Responsable
- Nom : daniel choquet