A new state-of-the-art instrument is now available for use at the cryo-electron microscopy facility of the UAR IECB.  This latest-generation automated transmission electron microscope - a ThermoFisher Glacios2 - was  funded by the Nouvelle Aquitaine region via the CPER and EquipEx+ NanoCryoClem grant. Installed during  the second semester of 2024,  this Glacios2  is now fully operational.

ThermoFisher Glacios2

What are the specifications of this equipment ?

This latest-generation instrument is equipped with an X-FEG electron gun (200 kV acceleration) for improved electron beam coherence, a robotised grid loader (for up to 12 samples), a SelectrisX energy-loss filter and a Falcon 4i direct electron detector.

• The SelectrisX filter improves the collected signal by eliminating inelastic electron scattering, thus significantly  reducing background noise in thick samples.

• The Falcon 4i camera displays an excellent efficiency (high signal-to-noise ratio) at high electron fluxes, enabling optimised acquisition times.

• Coupled with additional software and hardware enhancements (Aberration-Free Image Shift, Fringe-Free lllumination),very high acquisition throughputs can be achieved (typically >500 acquisitions/hour).

What benefits does this equipment bring to the analysis of samples ?

Overall, the improvements made to this generation of microscope enable very high throughput data collection, with superior image quality over the previous generation. Significant gains are obtained in the analysis of isolated particles (cryo-SPA) and cryo-electron tomography (cryo-ET).

• In cryo-SPA: only  a few hours of acquisition suffice to obtain 1,500 to 2,000 high-resolution micrographs, enabling different samples to be screened in a single session. Acquiring a maximum of 10,000 images per session (24 hours) allows the the obtention of high quality density maps with resolutions of 2 to 2.5 Å, on proteins as varied as micelle-embedded porins , small soluble proteins, ribosomes or fiber assemblies (amyloids, tubes, flagella, etc.).

A) 2.37 Å resolution density map f equine apoferritine obtained by  cryo-SPA . B) Corresponding model of the apoferritin 24mer generated by IA (ModelAngelo) from the density map.

• In cryo-ET: compared with  previous generations of instruments, the presence of the SelectrisX energy-loss filter allows data collection on thicker samples, and more contrasted images of thin samples. The increased stability of the column and sample holder means that higher magnifications  can be attained. Advanced software integration drastically reduces preparation and acquisition times (+50% acquisition speed in symmetrical acquisition scheme from -60° to +60°).

What are the access conditions for using Glacios2 and the other facilities on the platform ?

The Glacios2 is accessible via UAR3033 for national and international users. It is the latest addition to a range of equipment for high-resolution screening and structural analysis of biological and synthetic macromolecules, including a Philips CM120 (screening at room temperature), a ThermoFisher Talos L120C (morphological analysis, at room temperature or cryogenically) and a ThermoFisher Talos Arctica (cryo-SPA of proteins).