The new Thermo Scientific™ Krios™ G4 Cryo Transmission Electron Microscope (Cryo-TEM) enables you to unravel life at the molecular level—easier, faster and more reliably than ever before. The most compact TEM in its class, the Krios G4 Cryo-TEM consists of a highly stable 300 kV TEM platform and the industry-leading Autoloader (cryogenic sample manipulation robot), making it ideally suited for automated applications such as single particle analysis (SPA), cryo-electron tomography (cryoET) and micro electron diffraction (MicroED). Through a thorough redesign of the mechanical base frame and system enclosure, the microscope height has been reduced to below 3 meters, which allows for instrument installation in labs with a ceiling height below 3.04m (~10 ft), thereby avoiding costly room renovations. Designed-in connectivity ensures a robust and risk-free pathway throughout the entire workflow, from sample preparation and optimization to image acquisition and data processing.
The Krios G4 Cryo-TEM has improved ergonomics for easier sample exchange. Data acquisition set up is easier and faster thanks to enhanced automation, systematic user guidance and advanced performance monitoring (APM), a built-in self-diagnostic function that ensures microscope alignments are optimal for acquiring high-resolution data. Simultaneously, the system’s productivity and high-resolution performance have been further enhanced through a combination of new optical modes, improved optical specifications and on-the-fly pre-processing.
Fits more easily into new and existing labs Installing a high-end cryo electron microscope can be challenging and often requires significant room renovations because of instrument size. Thanks to its completely redesigned mechanical base frame and system enclosure, the Krios G4 Cryo-TEM now has a system height of <3 m, avoiding these costly and challenging renovations. As part of the redesign, the system ergonomics have also been improved. Specifically, the sample loading area has been brought to a physically lower position, allowing convenient and safe access; there is no need to climb a ladder to load precious cryo-samples. Close to the sample loading area, an interactive touch screen is available to indicate/control key microscope parameters, facilitating the sample loading process. This is especially beneficial when the operating room is remotely located.
Maximized productivity The Krios G4 Cryo-TEM features a built-in self-diagnostic function (APM) which evaluates if microscope alignments are optimized for acquiring high-resolution data. Automated alignment routines allow the instrument to be tuned to its optimal starting point for SPA or cryoET experiments. Combined with the instrument’s thermal and mechanical stability, APM can help ensure that ideal alignment is available for all users. Additionally, the integrated Thermo Scientific EPU Software has the ability to automatically perform daily tuning of essential alignments such as focus, eucentricity correction, stigmation and coma correction. The automated data acquisition itself is accelerated up to 4x through the use of image/beam shifts rather than a number of mechanical stage movements. This is possible due to aberration-free image shift (AFIS), a new optical mode which performs large beam shifts without off-axis coma and astigmatism, as well as the collection of more images per foil hole with fringe-free imaging (FFI). EPU Quality Monitor is an on-the-fly pre-processing tool (consisting of motion correction and CTF estimation, including derived parameters) that evaluates the acquired SPA data during the actual acquisition process. This allows you to judge the quality of the acquired data, and consequently optimize the data acquisition, while it is happening. This way, the highest quality data can be acquired in the most efficient way.
Best image quality for high-resolution 3D reconstruction The Krios Cryo-TEM has a proven track record of high-resolution imaging for a wide variety of particles: the vast majority (>95%) of published structures at or below 4 Å have been determined using Thermo Fisher Scientific Cryo-TEMs. (Determined via analysis of EMDB data. February, 2019.) To allow reconstruction of increasingly smaller molecules at increasingly higher resolutions, the improved information limit (0.12 nm) and linear distortion below 0.5% ensure the best possible boundary conditions for ultimate high-resolution imaging. Furthermore, the Krios G4 Cryo-TEM can be equipped with the new Thermo Scientific™ Falcon™ 4 Detector (faster and more sensitive than its predecessors) and the Thermo Scientific Phase Plate Solution.
Workflow connectivity Sample screening is an essential component of a successful cryo-EM workflow, allowing verification of sample quality in terms of both biochemistry and vitrification. The Krios G4 Cryo-TEM fits seamlessly into SPA and cryoET workflows, with convenient and contamination-risk-free sample transfer throughout the workflow.