Field Emission Cryo-electron Microscope

Cryo-electron microscopy (cryo-EM) has taken enormous flight in recent years. Atomic level structural analysis of viruses and proteins derived by cryo-EM using SPA workflows requires high stability hardware and software. JEOL proudly announces its latest offering in cryo-TEMs to facilitate this development in cryo-EM with the CRYO ARM™ 300. The CRYO ARM™ 300 achieves unprecedented resolution and stability thus allowing for the automatic and unattended acquisition of image data for Single Particle Analysis. Figure shows the 1.29Å structure of mouse apo-ferritin obtained by Fujita et al. on the CRYO ARM 300 at Spring8 (Japan).

The system is composed of an autoloading specimen stage cooled to liquid nitrogen temperatures and a cryo-storage device for long-term storage of up to 12 frozen-hydrated specimens. Liquid nitrogen is automatically supplied to both the stage and storage system as required. The autoloader allows loading and retrieval of up to 4 grids at a time without impacting the remaining samples in the cryo-storage device. Specimens are stored and labeled using a unique system fully transparent to the operator. These unique capabilities enable beamline-like scheduling of microscopy.

The cold FEG produces a high-brightness electron beam with a very small energy spread, thus offering high temporal coherency. In addition, spatial coherence is improved resulting in the CRYO ARM™ 300 achieving superior resolution and contrast compared to any 300 kV cryo-TEM currently on the market.

Equipped with an improved in-column energy filter (Omega filter), the CRYO ARM™ 300 acquires energy filtered images and energy loss spectra. Zero-loss imaging with the CRYO ARM™ 300 yields data with higher contrast due to reduced chromatic aberration. The stability of the filter has been greatly improved (see figure). This enables SPA runs that only require 2 adjustments of the zero-loss peak position per 24 hours. Setting up the Omega filter has never been easier with a new Auto Adjust function making sure every user can properly set up the filter for data acquisition.

The CRYO ARM™ 300 is fully compatible with the JEOL Automated Data Acquisition System (JADAS) and SerialEM (UC Boulder). 

The hole-free phase plate (HFPP) consist of a thin, continuous carbon film placed in the back focal plane of the objective lens, thus providing a substantial improvement in image contrast of frozen-hydrated specimen. Manufacturing of the HFPP uses a unique methodology resulting in robust and reliable performance at reasonable prices.

The CRYO ARM 300 can be outfitted with so-called Köhler illumination, resulting in a marked reduction of the fringes at the edge of the beam. This in turn allows using a narrow (parallel) electron beam when images are taken using Coma Free Image Shift (CFIS), or beam/image shift, inside a single hole in SPA runs, or even across holes in the quantifoil (see figure).

Auto focus, auto coma-free alignment, auto parallel-beam illumination and other automated adjustments are available, enabling image acquisition under optimum conditions.

*1 & 2: Optional unit. *3: Images acquired with the bottom mount camera are used.

GroEL structure at 1.98 Å resolution achieved by only 504 micrographs, a dramatic improvement from 3.1 Å resolution from 1,883 micrographs in a previous study. (as of Oct. 26, 2020 at EMDB)

Data courtesy of Dr. Junso Fujita at Osaka University

Cryo-electron micrograph (left), 3D density map (center) and fitted atomic model (right) of human hemoglobin obtained by high speed data collection, 850 movies per hour.

Specimen courtesy of Dr. Miki Kinoshita at Osaka University

2.5 Å resolution maps of the photosystem I trimer from Acaryochloris marina viewed from the stromal side perpendicular to the membrane plane (left) and from the side of the membrane plane (right).

Data courtesy of Dr. Koji Yonekura at RIKEN, Spring-8 Center

Electron diffraction pattern of a thin catalase crystal acquired with Omega filter showing clear diffraction spots visible to ~2.1 Å along the diagonal axis.

Data courtesy of Dr. Koji Yonekura at RIKEN, Spring-8 Center

Cryo-electron tomogram of isolated exosomes with a hole-free phase plate. The tomogram was obtained from micrographs of -60° to +60° tilt range at 2° steps.

Specimen courtesy of Dr. Naoomi Tominaga at National Cancer Center Research Institute and The University of Tokyo.