Focused Ion Beam-Scanning Electron Microscopy

Scanning Electron Microscopy (SEM) can be used to image the surface of a normal transmission electron microscopy block. SEM has less resolution and (far less) contrast but it only images from the surface of the object. Therefore if the surface is then removed then it can then image the remaining surface giving a stack of images.

Here we have used an ion beam to remove successive 10nm of surface. Left is an image series (aligned and corrected for angle) from a glomerular filtration barrier. Right is a 3D projection of the tissue. Yellow = glycocalyx, Blue = endothelial cell, Red = glomerular basement membrane and Green = podocytes

It might be worth checking out the other 3D-SEM methodology using an internal diamond knife to cut the sections (15nm is attainable but 100-150nm normal for each slice, but much larger field of view possible). Or tilt-series tomography

This work is from Arkill et al 2014 and done in collaboration with Prof. Klaus Qvortrup at CFIM at the University of Copenhagen