In our normal experiment, we may use cryovials to freeze the samples, but when using liquid nitrogen for cryo preservation, the explosion of the cryovials often occurs, which will not only cause the loss of experimental samples, but may even cause damage to the samples. Injury to experimenters. So how to avoid this from happening?
Reason:
If you want to know how to solve this situation, of course, you need to understand why the cryovial will explode.
First of all, cryo preservation tubes cannot be stored directly in the liquid phase of liquid nitrogen. Because the tube body and tube cover of common cryo preservation tubes are of different materials, the rate of thermal expansion and contraction during freezing is also different. If the tube is placed directly into the liquid phase, it may allow liquid nitrogen to flow into the tube.
When resuscitating the sample next time, put the cryovial into a water bath at 37°C and the liquid nitrogen in the tube quickly vaporizes and expands, but the gas cannot escape from the tube in time it will causing explosion of cryovial.
solution:
1: Do not store the cryovial directly in the liquid phase, but in the gas phase. Or put it directly in the refrigerator to freeze, remember do not put it directly below the surface of the liquid nitrogen .
2: Use an internal thread cryovial. Of course, even the internal rotation cryotube cannot be directly placed in the liquid phase, but the low temperature tolerance of the internal rotation cryotube is better than that of the external screw cap, which can reduce the possibility of explosion and is relatively safer. The external spin cryovial is actually designed for mechanical freezing, so it is not suitable for liquid nitrogen storage.
3: So what should I do if I really need liquid phase preservation? In response to this problem, there are actually cryotube sleeves specially designed for this purpose, which can be used to seal the cryopreservation tube and put it into the liquid phase. Of course, it can also be sealed with parafilm, medical tape, etc. This way there will be almost no explosions.