Physiology and Biophysics

July 24, 2017

PBIO Seminar Series: Liangyi Chen

October 12, 2017 @ 9:30 am – 10:30 am
HSB G-328

High spatiotemporal resolution, three-dimension fluorescence imaging of biological samples in vivo

Dr. Liangyi Chen Professor Laboratory of Cell Secretion and Metabolism Institute of Molecular Medicine, Peking University, Beijing, China Host: Bertil Hille Abstract: I will give two stories. (i) One story describes unpublished ultrasensitive Hessian structured illumination microscopy that enables ultrafast and long-term super-resolution (SR) live-cell imaging. At a photon dose one order less than point-scanning microscopy, Hessian-SIM has achieved 88-nm and 188-Hz spatial-temporal resolution for live cells imaging and lasted thousands of images without artifacts. Operating at 1 Hz, Hessian-SIM enables hour-long, time-lapse SR imaging with mitigatable photobleaching, highlighting the possibility of achieving SR imaging with commonly used fluorophores for an unlimited period of time. (ii) The second story is our recent Nature Methods paper, our invention of the fast high-resolution miniature two-photon microscope for brain imaging in freely-behaving mice at the single-spine level. 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 mini-microscope 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 experiencing vigorous body and head movements or engaging in social interaction.