EMS-002
Rapid Immersion Freezer
Ultrarapid freezing, when used in conjunction with appropriate accessory processing methods, has long been recognized to provide preservation of ultrastructure, localization of soluble inorganic and organic species, and preservation of antigenicity that is superior to that obtainable through conventional chemical fixation techniques and the use of cryoprotectants. Furthermore, it is the only procedure currently available for reproducibly capturing events that occur on a time scale of less than a few seconds.
Successful ultra-rapid freezing requires that heat be withdrawn so rapidly
from an unfixed, un-cryoprotected sample that no ice crystal damage is visible
at the electron microscopic level of analysis. This is not a trivial undertaking,
and until recently, the improvements gained through ultrarapid freezing were
often paid for in terms of decreased productivity. However, over the last
several years, improvements in methodology and the introduction of refined
equipment for the ultrarapid freezing of biological samples has significantly
improved both the ease of application of the technique and the yield of well
preserved samples. The EMS-002 Rapid Immersion Freezer allows
for reliable, virtually routine freezing of biological samples.
Features
- Removable Drop Anvil Assemble
- Specimen Holder
- Stainless Steel Liquid Nitrogen Dewar
- Cryogen Temperature Controller
- Drop Release
- Removable Cryogen Holder for safe disposal of Cryogen
- Frozen Specimen Work Station
Process of Ultra-Rapid Sample Cooling
The EMS-002 achieves ultra-rapid cooling by quenching the sample in liquid propane or other suitable cryogen, cooled to near liquid nitrogen temperature. The EMS-002 accomplishes this by using a Stainless Steel vacuum insulated Dewar and a Copper liquefaction chamber. Liquid Nitrogen is poured into the Dewar to a level determined by the user. The initial cooling of the cryogen liquefaction chamber takes about fifteen to twenty minutes.
Gaseous propane is then admitted to the liquefaction chamber slowly enough to allow it to condense and fill the chamber with liquefied propane. The Propane is allowed to cool to near liquid nitrogen temperature supervised by the digital temperature controller while a sample is being prepared for freezing. The device requires only about ten minutes to cool to operating temperature after the first filling of propane, and less than five minutes after subsequent fillings.
The operator can increase and decrease the rate of cooling by readjusting the level of liquid nitrogen in the Dewar. Heaters, built into the chamber walls; powered by a temperature controller, evenly warms the propane above its freezing point. The controllers temperature is set for the kind of Cryogen being used. -185°C for use with commercial grade propane.
Chemically pure propane (map. 190°C) can also be used, but it is significantly more expensive than commercial grade propane and confers no particular advantage. Ethane and a non-flammable cryogen, SUVA-124 produced by Dupont can also be used as a cryogen in this instrument. When using flammable cryogens like Propane & Ethane we recommend using the EMS-002 in a fume hood.
Sample Preparation
The sample can be prepared using any favorite size EM Grid if the system is being used for Cryo-TEM or Panama hat-shaped specimen carriers for Freeze-Fracture or Freeze Substitution. Once the sample is applied to the EM grid for instance, the excess must be carefully blotted away with a small piece of filter paper. Remember, the goal is to form a thin meniscus of specimen across the holes in the grid. Once achieved, insert the specimen holder in the “Drop Anvil” of the EMS-002.
For Freeze Fracture specimens, a thin spacer, typically an EM Slot grid; is placed on the top of the sample hat, and a second hat is placed upside down on the sample and serves to prevent the sample from being crushed. If the specimen is large and sturdy enough that it can be supported at its periphery, a hole can be made in one or both hats to allow the propane to directly contact the specimen.
Results and Techniques
The technique provides higher rates of cooling than can be attained by plunging the sample into the cryogen by hand, because the high velocity & accuracy the sample entering the cryogen. 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 has been applied to many types of specimens: aqueous suspensions and emulsions: tissue culture cells: suspensions of a wide variety of animal and plant cells: and tissues. Specimens frozen with the EMS 002 may be freeze fractured (knife cut or double replica), freeze substituted, frozen thin sectioned or freeze dried. The samples may also be used for Cry-SEM or TEM.
Temperature
Controller
Allows the user to set desired hold temperatures of the Cryogen being used. The easy to use controller also has a “settable” alarm to alert the user that the cryogen is warming up and the unit needs attention before the cryogen reaches evaporation temperature.
Recycling & Operating Costs
The recycling time of the device is less just a few minutes, just long enough so it will be ready for you when you finish processing the last sample. The operating cost is about 47 cents per sample depending on the price of Liquid Nitrogen. The device will operate for about two hours on ten liters of liquid nitrogen, including the initial cool down.
Applications:
- Cryofixation of Virus partials
- Cryofixation of Isolated or assembled macromolecules
- Cryofixation of Emulsions, Paints and Polymers.
- Cryofixation of Suspensions & Tissues for Cryo- Techniques like: Freeze Fracture/Etch, Freeze Drying, Freeze Substitution, CryoSEM and CryoTEM.
Advantages:
- Economical, Universal Application Rapid Freezing Unit
- Plunge freezing with temperature controlled cryogen.
- Frozen samples handled under cold dry nitrogen atmosphere.
- Rapid setup & easy use
- Safe operation and Easy Cryogen Disposal
- Reproducible results
- High & Low set points for cryogen control.
Specifications, EMS-002 Rapid Immersion Freezer
| Dimensions: | 11"W x 13"D x 14"h (279mm x 330mm x 356mm) |
| Electrical: | 100vac-240vac 50/60Hz 3a |
| Operational Temperature range: | +30 to –200°C |
| Liquid Nitrogen Consumption: | 1-2 liters per hour |
| Cryogen Volume: | 20 ml |
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 LN2 level in the Dewar automatically.
Metal Mirror Impact Freezing Fixtures: Allow to 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
tweezers specifically for use with the Plunge Freezer that is “self-locking”.
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 by rapid freezing
by plunging into liquid cryogen. Fits directly into the drop anvil
on the plunge freezer.
Ordering Information
| 37000 | EMS 002 Plunge Freezer |
$6495.00 |  |
| 37000-S | Cryo Transfer Face for SEM | $2,895.00 | |
| 37000-T | Cryo Transfer Face for TEM | $2,395.00 | |
| 37015 | Propane Transfer System | $525.00 | |
| 37454 | Automatic Liquid Nitrogen Filler | $3,150.00 | |
| 37455 | Metal Mirror Kit | $2,795.00 | |
| 37456 | Diamond Anvil | $975.00 | |
| 37457 | Environmental Chamber | $5,250.00 | |
| 37458 | Freeze Forceps | $42.00 | |
| 37459 | Muscle Biopsy Clamps | $495.00 | |
