Selectris and Selectris X Imaging Filters Features

Atomic-resolution cryo-EM energy filters

Designed for stability and speed, Thermo Scientific Selectris and Selectris X Imaging Filters represent a significant advancement in electron microscopy, providing exceptional image clarity.

Selectris Energy Filter 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

Falcon 4i Direct Electron Detector

  • Unsurpassed image quality through higher DQE 
  • Large pixels with high signal-to-noise ratio (SNR) 
  • Higher throughput for more images per hour
  • Lossless data compression with electron event representation (EER)

Automated electron energy filter 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

Electron energy filter technology

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

 

When paired with the latest generation Thermo Scientific Falcon Direct Electron Detector, Selectris Filters allow you to obtain high- resolution structures quickly, revealing new biological insights. The incorporated Falcon 4i Detector 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, cryo-electron tomography, and integrative structural biology, these filters are fully integrated into and our instrument operation software.

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

Selectris X Imaging Filter

The Selectris X Imaging Filter was designed for researchers seeking industry-leading optical performance, while the Selectris Imaging Filter 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.

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

How energy-filtering transmission electron microscopy works

Upon interacting with the sample, electrons may scatter elastically or inelastically. A Selectris Imaging Filter allows elastically scattered electrons to pass through, removing the noise caused by these electrons and increasing both signal-to-noise ratio (SNR) and contrast.

 

Using 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) while simultaneously 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 eV) and even higher resolution compared to an unfiltered image. This is because the B-factor has been reduced, meaning fewer particles are needed to obtain a certain resolution.

Graph showing the energy filtering on 200 kV cryo-TEMs

Experiment

Number of particles

Resolution (Å)

B-factor
10 eV 102,200 2.14 89.3
20 eV 102,200 2.26 99.5
Unfiltered 102,200 2.34 106.1


Additionally, a narrower energy slit width (10 eV) makes it possible to obtain equivalent resolution (370k) with fewer particles 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.

Hear from scientists using the Selectris Imaging Filters

“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

"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

Selectris Imaging Filter specifications

Selectris Imaging Filter
Position Bottom mounted
Stability Slit drift <± 1.5eV/24hr
Zero-loss centering Automated
Filter tuning Automated
TEM operating voltage 200 kV, 300 kV

Falcon 4i Direct Electron Detector
Sensor 4,096 × 4,096 pixels, ~ 5.7 x 5.7 cm
Pixel size 14 x 14 µm2 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 third party software via TEM scripting

For Research Use Only. Not for use in diagnostic procedures.