2023/03/01 Petar Petrov

Petar Petrov

Postdoctoral Scholar at University of California, Berkeley

Date and time: March 1st, 2023
Wednesday, at 8am PST / 11am EST / 4pm GMT / 5pm CET / midnight China

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Laser phase-contrast Cryo-EM and associated computational opportunities

A phase plate can provide optimum image contrast for weak-phase objects in transmission  electron microscopy, but approaches toward realizing a phase plate have suffered from  instabilities. We have developed a phase plate that is based on coherently phase-shifting the  electron wave function by a laser beam, which is built up to a record-high intensity of ~400  GW/cm^2 by resonance in a Fabry-Perot cavity. We have demonstrated contrast enhancement  with the laser phase plate (LPP) and shown the long-term stability of the device, as well as  generated a high-resolution map of 20S proteasome particles using a standard single-particle  cryo-electron microscopy (Cryo-EM) workflow. 

This talk will focus on our recent work to move beyond proof-of-concept, as well as the  computational opportunities that lie ahead. To demonstrate the benefits of the LPP to Cryo-EM  as well as cryo-electron tomography, we will soon begin working with a state-of-the-art  microscope equipped with a spherical aberration corrector, gun monochromator, and post column energy filter. We will explore improvements to the phase plate design and pursue new  strategies for image acquisition and processing, such as high-resolution two-dimensional  template matching.