In transmission electron microscopy (TEM) an image is formed by a beam of electrons passing through specimens such as ultrathin sections of tissue/cells or material deposited on an EM grid. Contrast in the image arises from differential absorption of electrons by native or stained structures within the specimen.

The Wolfson Bioimaging Facility is exceptionally well equipped to support a range of TEM applications with its two high specification microscopes.

• The FEI Tecnai 12 is a 120 kV TEM most often used for routine imaging of ultrathin (< 100 nm) sections of conventionally processed biological specimens. It is also appropriate for negative staining of proteins, liposomes, exosomes, viruses, bacteria etc.
• The FEI Tecnai 20 is a 200 kV TEM capable of higher resolution imaging which can also be used to image thicker specimens, including creating tilt series for electron tomography. In addition it has cryo-TEM and scanning transmission electron microscopy (STEM) capabilities.     

Further information is available on sample processing, technical specifications of the Tecnai 12 and Tecnai 20 microscopes and the GW4 facility for high-resolution electron cryo-microscopy.