Cryo-EM Screening

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This service provides sample preparation by plunge-freezing, grid clipping for autoloader system and cryo-TEM imaging at 200 kV. A maximum of 1 specimen and 8 grids can be prepared and processed per unit of service. An optional “polishing” SEC step can be performed on thawed material by the Biophysics Unit, as and if specified in the request for this service. Glow discharging will be performed by either a Pelco EasyGlow, a Quorum GloQube, or Solarus II plasma cleaner device. Plunge-freezing will be performed on a Thermo Scientific Vitrobot Mk IV or a Leica EM GP2. Applicants may provide TEM grid supports of preference, otherwise Facility Staff will use holey TEM grid supports available. Imaging will be provided for a maximum of 8 continuous hours per unit of service. Cryo-TEM imaging will be performed only in EF-TEM mode at 200 kV on a Thermo Scientific Glacios equipped with a Falcon 4i direct electron detector and Selectris X energy filter. Imaging conditions requested by the User, if provided, must be compatible with Facility practices. In case of grids showing optimal particle distribution and ice quality, this service can be extended for overnight data collection, if compatible with Facility Staff working hours. The User can also provide already-made cryo-TEM grids either unmounted or mounted on a Thermo Scientific cartridge. In case of an unmounted grid, clipping of the specimen in Thermo Scientific cartridges will be performed by Facility Staff. In case of User-provided already-clipped grids, these will be inspected by Facility Staff prior to acceptance. This service will only be performed by Facility Staff.