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Available on Thermo Scientific Krios and Glacios Cryo-TEMs, the Thermo Scientific Selectris and Selectris X Imaging Filters are post-column imaging filters that improve the contrast of TEM images, resulting in high-resolution structures up to atomic resolution. The zero-loss filtering of the Selectris Filters removes noise caused by inelastically scattered electrons, producing an increased signal-to-noise ratio (SNR) and better contrast. Designed for high stability, the zero-loss peak position of the Selectris Filters has minimized sensitivity to temperature variations in the environment, eliminating the need for frequent tuning.

With the Selectris Filters, zero-loss energy filtering is straightforward due to the thorough integration of software and hardware along with extensive automation and exceptional stability. Every mechanical and electron-optical element has been designed for stability and data reproducibility, enabling the unattended and reliable acquisition of large datasets with narrow energy slit widths (<10 eV). The capability to use these narrow slit widths provides an additional boost in contrast for single particle cryo-electron microscopy (cryo-EM), enhancing signal strength, resolution, and throughput.

Paired with the latest generation Thermo Scientific Falcon 4 Direct Electron Detector, Selectris Filters allow you to obtain high-resolution structures quickly, revealing new biological insights. Incorporated Falcon 4 camera with electron event representation (EER) enables efficient file size compression, super-resolution capabilities and maximized sensitivity for all use cases. To further increase the productivity and ease-of-use of your cryo-EM workflows for single particle analysis and cryo-electron tomography, these filters are fully integrated into Thermo Scientific EPU Software, Thermo Scientific Tomography Software, and our instrument operation software.

Cryo-electron microscopy atomic-resolution of apoferritin.
Atomic-resolution structure of apoferritin, resolved to 1.2 Å by cryo-electron microscopy with Selectris X Imaging Filter.

Selectris X Filter – taking the next step toward atomic resolution

The Selectris X was designed for researchers seeking industry-leading optical performance, while the Selectris is ideal for those who require maximum efficiency and throughput. Expanding on the stability, ease-of-use, and performance of the Selectris platform, the Selectris X Imaging Filter offers an even more sophisticated electron optical system for further aberration correction. This results in extremely low distortion characteristics in both the image and energy domains, opening the way to true atomic-resolution structures.

How energy-filtering transmission electron microscopy works

Upon interacting with the sample, electrons may scatter elastically or inelastically. The Selectris Imaging Filter allows elastically scattered electrons to pass through, thereby enhancing image contrast. The intrinsic mechanism is that through removing the noise caused by inelastically scattered electrons, the signal-to-noise ratio (SNR) and the contrast is increased.

The capability to use a very stable narrow slit width (<10 eV) provides an additional boost in contrast for single particle cryo-electron microscopy (cryo-EM) and cryo-tomography (cryo-ET), also enhancing resolution and throughput.

For example, let’s compare reconstructions of proteasome 20S with the same amount of particles (see table). A narrower energy slit (i.e. lower energy) leads to higher resolution compared to a larger slit width (20 keV) and even more improved compared to unfiltered image. This is because the B-factor has been reduced meaning less particles are needed to obtain a certain resolution.

Additionally, a narrower energy slit width (10 eV) translates into a lesser number of particles needed to obtain equivalent resolution (370k) compared to using a wider energy slit (see figure and graph). As a result, with the Selectris X Imaging Filter, you can obtain results faster with less data or maximize your resolution efforts.

Energy-Filtering Transmission

Experiment

# Particles

Resolution (Å)

B-factor

10 eV102,2002.1489.3
20 eV102,2002.2699.5
Unfiltered102,2002.34106.1
Proteasome graph
Proteasome protein

Getting to lower energy slit widths, such as 5 or 10 eV, requires a very stable filter to avoid interruptions for filter alignment.

“We’re impressed with the stability of both the hardware and the software.  Due to the enhanced performance and stability, all our COVID-19 work is now done on the Selectris X Imaging Filter.  We routinely collect 5 eV tomograms, which was previously impossible.”

Alistair Siebert, Principal Electron Microscopist for the electron Bio-Imaging Centre (eBIC), Diamond Light Source

Alistair Siebert, Principal Electron Microscopist
Dr. Juergen Plitzko, Max Planck Institute for Biochemistry, Martinsried Germany

"The Selectris X Imaging Filter is clearly favored by us due to its stability and robustness, particularly when it comes to data collection for cryo-EM and cryo-ET that is carried out over extended periods of time. Once tuned, the filter is stable for over a month. The zero loss peak only moves by 1 eV over a week or even two!”

Dr. Juergen Plitzko, Max Planck Institute for Biochemistry, Martinsried Germany

What's possible with Selectris at 200 kV and 300 kV

Selectris and Selectris X Imaging Filters are fully compatible with Glacios Cryo-TEM, featuring 200 kV XFEG optics. The Glacios Cryo-TEM bundles all this into a small footprint that simplifies installation.

Human hemoglobin collected on Glacios Cryo-TEM with Selectris X Imaging Filter resolved at 3.4 Å.
Human hemoglobin collected on Glacios Cryo-TEM with Selectris X Imaging Filter resolved at 3.4 Å.
Human hemoglobin collected on Krios Cryo-TEM with Selectris X Imaging Filter resolved at 2.0 Å.
Human hemoglobin collected on Krios Cryo-TEM with Selectris X Imaging Filter resolved at 2.0 Å.

Key Features

Designed for stability

  • Narrow (<10 eV) zero-loss energy filtering offers enhanced contrast for higher resolution reconstructions
  • Sophisticated aberration correction, low image distortions, and uniform energy resolution over entire field of view
  • Minimized sensitivity to temperature variations

Straightforward operation

  • Fully integrated with Thermo Scientific instrument operation software, as well as EPU Software and Tomography Software for data collection.
  • Automated filter tuning completed in minutes
  • No need to interrupt data collection for zero-loss centering

Falcon 4 Direct Electron Detector

  • High detective quantum efficiency (DQE)
  • High speed, routinely capable of producing 300+ movies/hour
  • Built-in electron event representation (EER) for full temporal resolution (240 fps to disk) - no need for fractionating at time of acquisition
  • Super resolution without file size penalty

Fast, infrequent tuning

  • Tuning can be completed automatically within minutes, on the rare occasion that filter tuning is necessary
  • Experimental runs without interruption, for smooth daily operation and efficient data collection

Specifications

Style Sheet for Products Table Specifications


Imaging Filter

PositionBottom mounted
StabilitySlit drift <± 1.5eV/24hr
Zero-loss centeringAutomated
Filter tuningAutomated
TEM operating voltage200 kV, 300 kV


Falcon 4 Direct Electron Detector Camera

Sensor4,096 × 4,096 pixels, ~ 5.7 x 5.7 cm
Pixel size14 x 14 um2 pixel size
File formats
  • EER super-resolution up to 16k x 16k.  All counted frames (~240 fps) accessible/written to disk, fractionation not required
  • MRC
Detection modes
  • Electron counting mode
  • Survey mode (fast linear mode)
Automation
  • Integrated in Thermo Scientific EPU and Tomography software
  • Compatible with 3rd party software via TEMscripting

Resources

Apoferritin resolved at 1.7 Å using 10 eV filtering on the Glacios Cryo-TEM with Selectris X.

GABA-A receptor human membrane protein resolved at 2.4 Å (~200 kDa) with 94k particles compared to 2.8 Å resolution and 127k on an unfiltered sample by the Glacios Cryo-TEM with Selectris X. Sample courtesy of MRC-LMB Cambridge.

Human hemoglobin (small molecule, 64 kDa) resolved at 3.4 Å with the Glacios Cryo-TEM with Selectris X.

 

Cryo-EM: What&#39;s Next

Cryo-EM: What's Next

Register to view on-demand presentations covering the Selectris capabilities, a behind-the-scenes look at R&D filter development, and record-breaking structure resolution results for single particle analysis and cellular cryo-tomography using the Selectris Filter. Learn about the potential applications with high resolution for small proteins (<100kDa), proper model building and corrected chemistries.

Register now

Apoferritin resolved at 1.7 Å using 10 eV filtering on the Glacios Cryo-TEM with Selectris X.

GABA-A receptor human membrane protein resolved at 2.4 Å (~200 kDa) with 94k particles compared to 2.8 Å resolution and 127k on an unfiltered sample by the Glacios Cryo-TEM with Selectris X. Sample courtesy of MRC-LMB Cambridge.

Human hemoglobin (small molecule, 64 kDa) resolved at 3.4 Å with the Glacios Cryo-TEM with Selectris X.

 

Cryo-EM: What&#39;s Next

Cryo-EM: What's Next

Register to view on-demand presentations covering the Selectris capabilities, a behind-the-scenes look at R&D filter development, and record-breaking structure resolution results for single particle analysis and cellular cryo-tomography using the Selectris Filter. Learn about the potential applications with high resolution for small proteins (<100kDa), proper model building and corrected chemistries.

Register now

Applications

Structural biology research

Structural Biology Research

Cryo-electron microscopy enables the structural analysis of challenging biological targets such as large complexes, flexible species and membrane protein.

Drug discovery

Drug Discovery

Learn how to take advantage of rational drug design for many major drug target classes, leading to best-in-class drugs.

Infectious disease research

Infectious Disease Research

Cryo-EM techniques enable multiscale observations of 3D biological structures in their near-native states, informing faster, more efficient development of therapeutics.

Techniques

Single Particle Analysis

Single particle analysis (SPA) is a cryo-electron microscopy technique that enables structural characterization at near-atomic resolutions, unraveling dynamic biological processes and the structure of biomolecular complexes/assemblies.

Learn more ›

Cryo-Tomography

Cryo-electron tomography (cryo-ET) delivers both structural information about individual proteins as well as their spatial arrangements within the cell. This makes it a truly unique technique and also explains why the method has such an enormous potential for cell biology. Cryo-ET can bridge the gap between light microscopy and near-atomic-resolution techniques like single-particle analysis.

Learn more ›

Integrative Structural Biology

To understand protein function, you need complex and structure information beyond individual proteins. Integrative structural biology combines mass spectrometry and cryo EM for the determination of large dynamic complex structure.

Learn more ›

Single Particle Analysis

Single particle analysis (SPA) is a cryo-electron microscopy technique that enables structural characterization at near-atomic resolutions, unraveling dynamic biological processes and the structure of biomolecular complexes/assemblies.

Learn more ›

Cryo-Tomography

Cryo-electron tomography (cryo-ET) delivers both structural information about individual proteins as well as their spatial arrangements within the cell. This makes it a truly unique technique and also explains why the method has such an enormous potential for cell biology. Cryo-ET can bridge the gap between light microscopy and near-atomic-resolution techniques like single-particle analysis.

Learn more ›

Integrative Structural Biology

To understand protein function, you need complex and structure information beyond individual proteins. Integrative structural biology combines mass spectrometry and cryo EM for the determination of large dynamic complex structure.

Learn more ›

Style Sheet for Instrument Cards Original

 

Related Products

Krios G4 Cryo-TEM
Glacios Cryo-TEM
Falcon 4
EPU 2 Software
Tomography 5 Software
EM Services for Cryo-Electron Tomography
EM Services for SPA


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