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
• suspensions and tissues

for cryo-techniques like:

• freeze fracture/etch
• freeze drying
• freeze substitution
• CryoSEM
• CryoTEM

Advantages

Ultra-rapid freezing with the EMS-002 withdraws heat so rapidly from an unfixed, un-cryoprotected sample that no ice crystal damage is visible at the electron microscopic level of analysis.   Compared to conventional chemical fixation techniques and the use of cryoprotectants, ultra-rapid freezing:

• preserves ultrastructure
• improves localisation of soluble inorganic and organic species
• preserves antigenicity
• captures events that occur on a time scale of less than a few seconds.

Features:

• Removable drop anvil assembly
• Specimen holder
• Stainless steel liquid nitrogen Dewar
• Cryogen temperature controller
• Drop release
• Removable cryogen holder for safe disposal of cryogen
• Frozen specimen work station

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. 

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

Optional Accessories

• Climate Controlled Environmental Chamber
  Inhibits air-drying and pre-cooling of sample prior to freezing. Allows easy sample blotting to achieve the optimal amount of sample on your grid.
  
  
• Automatic Liquid Nitrogen Filling
  Keeps a constant liquid nitrogen level in the Dewar.
  
  
• Propane Transfer System
  
  
• Cryo Transfer Face for SEM
  
  
• Cryo Transfer Face for TEM
  
  
• Metal Mirror Impact Freezing Fixtures
  Allow a quick change from plunge freezing to impact freezing.
  
  
• Diamond Anvil
  Special freeze anvil with real diamond plate for better rapid freezing and easier specimen removal. Does not require polishing like standard copper anvils.
  
  
• Freeze Forceps
  Special self-locking tweezers specifically for use with the plunge freezer. Extra sets allow quicker turn around when freezing multiple samples.
  
  
• Muscle Biopsy Clamps
  Clamps designed for human muscle biopsies to keep the muscle from contracting during fixation. Now it is possible to improve the morphology of the sample through rapid freezing by plunging into liquid cryogen. Fits directly into the drop anvil on the plunge freezer.

Specifications:
Dimensions: W279mm x D330mm x H356mm
Electrical: 100-240VAC 50/60Hz 3A
Operational Temperature range: +30 to -200°C
Liquid Nitrogen Consumption: 1-2 litres per hour
Cryogen Volume: 20 mL