Cryogenic transmission electron microscopy (cryo-TEM) can solve near-atomic-resolution structures of purified and in situ macromolecular targets.

We have a specially optimised microscope allowing macromolecules to be studied close to their native state by preserving samples through cryo-vitrification. The microscope operates at higher accelerating voltages (200kV) and has several features that improve its efficiency and ability to deliver high-resolution structural information;

• A cold field emission gun (cold FEG) improves contrast and achievable resolution by improving electron beam quality.
• An in-column energy filter (omega filter) improves image useful contrast in thicker samples.
• A top-of-the-range K3 (Gatan) direct electron detector camera transfers signal from the sample to the camera with high efficiency and allows correction of sample motion, giving excellent image quality.
• An automated multiple specimen exchange system allows samples to rapidly be exchanged in and out of the microscope with low contamination rates, vastly improving sample screening and data collection efficiencies.
• Automated data collection software allows rapid automated or semi-automated collection of thousands of sample images, drastically enhancing image data volumes and achievable resolutions.

When combined, these features offer a paradigm shift in the capability of cryo-TEM, driving high quality research. 

Examples of use

This technique is excellent for:

• single particle imaging of protein complexes, viruses, protein-ribonucleic acid associations to understand the fundamental building blocks of life
• structural analysis of membranes in their native and cellular context in 3D at the nanometer-scale
• drug delivery studies (eg colloidal dispersions)
• biotechnology or tissue engineering including characterising synthetic lipid bilayers as models of cell membranes
• studying samples such as lung surfactant, which need to remain as close as possible to liquid phase so its structure and function can be correlated accurately

At the centre we have used cryo TEM to study:

• Plasmodium falciparum erythrocytes during invasion, infection and egress
• antibodies and allergic reactions

Equipment available

• JEOL cryoARM200

Images