English
 
User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Practical aspects of Boersch phase contrast electron microscopy of biological specimens

MPS-Authors
/persons/resource/persons182749

Lacher,  M.
Micro Systems Technology, Center of Advanced European Studies and Research (caesar), Max Planck Society;

/persons/resource/persons182769

Steltenkamp,  S.
Micro Systems Technology, Center of Advanced European Studies and Research (caesar), Max Planck Society;

/persons/resource/persons182763

Schmitz,  S.
Micro Systems Technology, Center of Advanced European Studies and Research (caesar), Max Planck Society;

/persons/resource/persons182738

Holik,  P.
Micro Systems Technology, Center of Advanced European Studies and Research (caesar), Max Planck Society;

Fulltext (public)
There are no public fulltexts available
Supplementary Material (public)
There is no public supplementary material available
Citation

Walter, A., Muzik, H., Vieker, H., Turchanin, A., Beyer, A., Golzhauser, A., et al. (2012). Practical aspects of Boersch phase contrast electron microscopy of biological specimens. Ultramicroscopy, 116, 62-72. doi:DOI 10.1016/j.ultramic.2012.03.009.


Cite as: http://hdl.handle.net/11858/00-001M-0000-0028-62EB-0
Abstract
Implementation of physical phase plates into transmission electron microscopes to achieve in-focus contrast for ice-embedded biological specimens poses several technological challenges. During the last decade several phase plates designs have been introduced and tested for electron ciyo-microscopy (cryoEM), including thin film (Zernike) phase plates and electrostatic devices. Boersch phase plates (BPPs) are electrostatic einzel lenses shifting the phase of the unscattered beam by an arbitrary angle. Adjusting the phase shift to 90 achieves the maximum contrast transfer for phase objects such as biomolecules. Recently, we reported the implementation of a BPP into a dedicated phase contrast aberration-corrected electron microscope (PACEM) and demonstrated its use to generate in-focus contrast of frozen-hydrated specimens. However, a number of obstacles need to be overcome before BPPs can be used routinely, mostly related to the phase plate devices themselves. CryoEM with a physical phase plate is affected by electrostatic charging, obliteration of low spatial frequencies, and mechanical drift. Furthermore, BPPs introduce single sideband contrast (SSB), due to the obstruction of Friedel mates in the diffraction pattern. In this study we address the technical obstacles in detail and show how they may be overcome. We use X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) to identify contaminants responsible for electrostatic charging, which occurs with most phase plates. We demonstrate that obstruction of low-resolution features is significantly reduced by lowering the acceleration voltage of the microscope. Finally, we present computational approaches to correct BPP images for SSB contrast and to compensate for mechanical drift of the BPP. (C) 2012 Elsevier B.V. All rights reserved.