Cryo transfer and tomography of thin-film frozen-hydrated/vitrified specimens for low- dose imaging and analysis.
- Ideal for specimens that require liquid- nitrogen cooling for transfer to the transmission electron microscope (TEM) for imaging and analysis
- Base temperature less than -175 °C
- Advanced mechanism for frost-free transfer
- Integrated specimen clamp for tool-free specimen mounting
- Extended field of view at high tilt up to 80°
- Resolution better than 0.34 nm
- Low drift rate of 1.5 nm/min-1
- Rapid cool-down to operating temperature
Cryo-electron tomography
Cryo-electron tomography is a well know technique used for the evaluation of biological specimens. Structural details are imaged in three dimensions in a transmission electron microscope at cryogenic temperatures to reveal information from specimens such as proteins and viruses.
Liquid nitrogen cooling for the transfer of frozen-hydrated/vitrified specimens
The Cryo Transfer Tomography Holder is an advanced single-tilt holder that provides cryogenic specimen cooling with an extended field of view at high-tilt angles up to 80°. Tomographic data can be acquired in TEMs with pole-piece gaps of approximately 5 mm.
Included with the Model 2550 Cryo Transfer Tomography Holder is a Cryo Work Station, a Temperature Controller, a Model 9010 Vacuum Storage Container, and a Specimen Clamp Tool.
Simple specimen loading and transfer
The innovative design of the specimen tip makes loading and unloading of the specimen very easy. To load a specimen, the holder is inserted into the Cryo Work Station or the TEM to cool down. The holder dewar and the Cryo Work Station are both filled with liquid nitrogen. The modular design of Cryo Work Station’s grid box allows you to reposition the reservoirs to enhance ease- of-use for both right- and left-handed operation.
Once a temperature of less than -175 °C is achieved, a specimen is loaded from the grid box into the holder tip. The holder accepts a 3 mm diameter TEM specimen grid, which is secured by the holder’s one-piece, integrated specimen clamp. The clamp automatically closes when the holder tip is retracted. Optionally, the specimen clamp can be closed with forceps or with the supplied specimen clamp tool. The thin profile of the clamp maximizes specimen visibility, even at high-tilt angles.
The specimen holder tip retracts inside an actively cooled cryo shield located within the end of the holder. This shield prevents any atmospheric water from condensing on the specimen during transfer to or from the microscope.
Rapid cool down, extended hold time
The Cryo Transfer Tomography Holder rapidly reaches a working temperature of less than -175 °C in either the Cryo Work Station or a TEM. Hold times in excess of 4 hours are readily obtained with the 200 ml dewar capacity. A zeolite absorption medium enhances dewar vacuum.
The Temperature Controller connects directly to the specimen holder dewar and displays the holder tip temperature.
Regenerating the zeolite
The dewar zeolite must be regenerated periodically. This process is made easy with the one-touch Zeolite Regeneration button on the Temperature Controller. Fischione recommends the use of vacuum pumping station to evacuate the dewar during regeneration.
Plasma cleaning
Prior to freezing thin films, TEM carbon support grids should be cleaned to remove hydrocarbons and to make the grids’ surface hydrophilic. Fischione recommends that you clean the support grids with the Model 1020 Plasma Cleaner or Model 1070 NanoClean.
Collision protection
Fischione’s advanced tomography holders are compatible with the TEM’s touch-alarm that stops goniometer movement if a pole touch occurs. Follow the microscope manufacturer’s recommendation for operating the goniometer at high-tilt angles.
Spécifications
| Holder type | A single-tilt holder for cryo transfer and tomography of thin-film frozen-hydrated/vitrified specimens. For transmission electron microscopes (TEMs) with a wider gap pole piece (an approximate 5 mm gap for tomographic studies). |
| Standard specimen cup/ holder tip material | Beryllium copper |
| Cryogen | Liquid nitrogen |
| Specimen grid size | 3 mm diameter |
| Field of view | Up to 1 mm |
| Resolution | 0.34 nm at 0° tilt |
| Drift | 1.5 nm/min-1 |
| Maximum tilt range | Up to ± 80° |
| Dewar capacity | 200 ml |
| Maximum operating temperature | Up to 110 °C |
| Maximum bake-out temperature | Up to 110 °C |
| Minimum operating temperature | < -175 °C |
| Time to reach minimum operating temperature | < 30 minutes (in microscope) |
| Hold time at minimum operating temperature | > 4 hours |
| Warranty | One year |
All specifications depend on the microscope model, pole-piece type, and aperture position. For ultimate resolution and drift performance, the TEM must meet the manufacturer’s specifications.