JEOL announces new cold field emission cryo-electron microscope: CRYO ARM™ 300 II

JEOL has announced the release of a new cold field emission cryo-electron microscope (cryo-EM), the CRYO ARM™ 300 II (JEM-3300). This new cryo-EM has been developed based on the concept of “Quick and easy to operate and get high-contrast and high-resolution images”.

Cryo Arm™ 300 II product development background

Recent improvement of resolution in single particle analysis (SPA) using cryo-EM has led to SPA as an essential method for structural analysis of proteins. To address this market, JEOL released the CRYO ARM™ 300 in 2017. Equipped with a cold field emission gun (Cold FEG) for enhanced resolution and a cryo-stage for loading multiple samples, the CRYO ARM™ 300 has continued to achieve best-in-class resolution for SPA.

However, the previous workflow of SPA using cryo-EM needs multiple electron microscopes because the workflow for sample screening and for image data acquisition are independent of one another. This problem gives rise to large operating costs for cryo-EM users. Since multiple microscopes must be used, it is inconvenient to transfer cryo-samples between the cryo-EMs. Therefore, users have been requesting one cryo-EM enabling the complete workflow from sample screening to image data acquisition. Furthermore, in order for various users to use the cryo-EM, an improvement of usability has been required, allowing anyone from novice users to professional users to smoothly operate the microscope.

To meet these requests, JEOL has developed a new cryo-EM, the CRYO ARM™ 300 II. This microscope achieves a great improvement in throughput for high-quality data acquisition with quick and easy operation compared with the previous CRYO ARM™ 300.

Cryo Arm™ 300 II main features:

High-speed imaging achieved by optimal electron beam control

• To support the complete workflow from sample screening to image data acquisition, it is of prime importance to improve throughput for image data acquisition. In the CRYO ARM™ 300 II, precise movement of the specimen stage is combined with excellent beam-shift performance for high-speed data acquisition. In addition, a unique “Koehler mode” illumination allows for uniform beam illumination onto a specific site on the sample, enabling more images to be acquired from a smaller area. These new technologies enable the CRYO ARM™ 300 II to deliver two times or higher throughput than the CRYO ARM™ 300.

Improved hardware stability for high-quality image acquisition

• In performing SPA, although acquisition of a great number of images improves throughput, this is not enough. High-resolution data reconstruction from a small number of images is required, and this is achieved by high image quality. For this objective, the CRYO ARM™ 300 II is equipped with a new cold field emission gun (Cold FEG). This FEG has previously been incorporated into the GRAND ARM™ 2, a high-end atomic resolution analytical electron microscope released in 2020. Like the case of the GRAND ARM™ 2, this new Cold FEG produces a highly stable probe current. The CRYO ARM™ 300 II is also equipped with a new in-column Omega energy filter which has excellent stability. This new Cold FEG and new Omega energy filter enable users to acquire superbly high signal-to-noise ratio images.

Higher operability through system improvement

• The CRYO ARM™ 300 II includes various system improvements. The microscope is equipped with the new JADAS (JEOL Automated Data Acquisition System for Cryo-EM) software (upgraded to version 4) for performing SPA. This JADAS 4 software, developed for novice users, provides improved operability for data acquisition.
• The new Omega filter incorporates an automatic self-adjustment system for reducing routine maintenance.
• The specimen stage of the microscope has excellent positional reproducibility. Even if the user transfers samples back and forth between the microscope column and sample storage, an initial low magnification image of the whole sample grid (global map) can still be used. It is also possible to stop image data acquisition and rapidly screen sample grids during this short stop of data acquisition.
• The automated specimen exchange system features storage of up to 12 samples. Sample grids can be kept clean in storage for weeks or longer without ice contamination of the samples.

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