EMS-002 Cryo Workstation, 240V

The EMS-002 Rapid Immersion Freezer allows for reliable, virtually routine freezing of biological samples. The EMS-002 achieves precision ultra-rapid cooling by quenching the sample in a cryogen, cooled to near liquid nitrogen temperature, using a stainless steel vacuum insulated Dewar and a copper liquefaction chamber. 

Applications: Cryofixation of virus partials, isolated or assembled macromolecules, emulsions, paints and polymers and suspensions and tissues. Cryo-techniques such as freeze fracture/etch, freeze drying, freeze substitution, CryoSEM and CryoTEM.

Easy Setup and Operation

Liquid nitrogen is poured into the Dewar. The initial cooling of the cryogen liquefaction chamber takes about fifteen to twenty minutes.

Gaseous cryogen (usually propane) is then added to the liquefaction chamber slowly enough to allow it to condense and fill the chamber with liquefied cryogen. 

The cryogen is allowed to cool to near liquid nitrogen temperature supervised by the user-configured digital temperature controller. The EMS-002 Cryo Workstation requires only about ten minutes to cool to operating temperature after the first filling of cryogen, and less than five minutes after subsequent fillings.

The rate of cooling can be controlled by adjusting the level of liquid nitrogen. Heaters, built into the chamber walls and actuated by a temperature controller, evenly warm the cryogen above its freezing point. 

Sample Preparation

Cryo TEM
The sample can be prepared using any size EM grid.  Once the sample is applied to the EM grid, the excess must be carefully blotted away. The goal is to form a thin meniscus of specimen across the holes in the grid, then insert the specimen holder in the Drop Anvil of the EMS-002.

Freeze Fracture and Freeze Substitution
Use a panama hat-shaped specimen carrier.  Place a thin spacer, typically an EM slot grid, on the top of the sample hat, and a second hat upside down on the sample, to prevent the sample from being crushed. If the specimen is large and sturdy enough, a hole can be made in one or both hats to allow the cryogen to directly contact the specimen.

Results and Techniques

Approximately 100 meters per second is the optimal plunging speed and provides more efficient heat exchange. The freezing is fast enough to capture rapid events and labile structures that are not seen in chemically fixed material.  

The technique provides higher rates of cooling than can be attained by plunging the sample into the cryogen by hand, because of the high velocity and accuracy of the sample entering the cryogen.

Fast Recycling

The recycling time of the EMS-002 Cryo workstation is only a few minutes, just long enough to be ready again when processing of the last sample is finished. The device will operate for about two hours on ten litres of liquid nitrogen, including the initial cool down.

Alternative Cryogens

Commercial grade propane is the most commonly used cryogen, for which the temperature is set for -185°C. Chemically pure propane (map. 190°C) can also be used, but it is significantly more expensive than commercial grade propane.

A non-flammable cryogen, SUVA-124 (by Dupont), and even Ethane can also be used as cryogens in the EMS-002 Cryo Workstation. 

NOTE: The EMS-002 should be operated in a fume hood when using flammable cryogens.