State-of-the-art 3D electron microscopy makes use of tilt-series, or the averaging of signals of many identical particles. A new option is provided by 3D STEM in which the electron beam is scanned in three dimensions, similar as the optical sectioning of confocal laser microscopy. This technique has become available with a meaningful vertical resolution due to the enlarged beam opening angle of the aberration corrected STEM. 3D STEM appears of particular interest for structural biology, while it offers fast imaging times, absence of drift problems, the possibility to image large area samples, the option to image thick samples and high sensitivity for specific labels. 3D STEM has been demonstrated to work for conventional thin sections.
The research was funded by NIH project grant R01-GM081801. Dr. David.W. Piston has taken over the role of principal investigator after the transfer of Dr. Niels de Jonge to the INM-Institute in Saarbruecken, Germany.
Monte-carlo calculations of beam-sample interactions are performed in collaboration with Prof. Dominique Drouin of the University of Sherbrooke (Canada) using Casino software.