Hitachi 2600N Scanning Electron Microscope at the UBC Bioimaging Facility
Scanning Electron Microscope (SEM) is a form of electron microscope in which the surface of samples is scanned with an electron beam. This form of microscopy allows for a detailed look at the surface composition and topography of a sample that is otherwise hard to view with the naked eye or with regular compound or dissecting light microscopes. It has a very high resolution, allowing the viewer to differentiate between structures that are very close together.
Dry, solid objects can be viewed with SEM provided that they are stable in a vacuum, this ensures that electrons will be able to actually come in contact with the object and that electrons released from an electron gun follow a path within the vacuum. When electrons hit the sample, electrons bounce off, along with X-rays, which are converted to a signal that eventually produces an image. Images produced are in black and white, while colours are often added later to emphasize certain structures or for artistic purposes.
Most samples are coated with some conducting material such as carbon or gold, metal samples do not require coating.
For our project, we used the Hitachi 2600N Scanning Electron Microscope to obtain our images. We sputter-coated our spore samples with palladium and gold after mounting them on carbon tape.
Some examples of SEM images:
Composite image by Martin Oeggerli, University Hospital Basel; 14 SEM scans by Ralf Buchner and Heidemarie Halbritter, University of Vienna
Photograph by Martin Oeggerli; Venus flytrap (Dionaea muscipula) pollen grains
Moss Spores & sem 