Why do cryovials explode? How to avoid it?

Why do cryovials explode? How to avoid it?

During the experiment, we may use cryovials to freeze samples, but when freezing with liquid nitrogen, cryovials often explode, which not only causes the loss of experimental samples, but may even cause damage to the samples. Experimenters cause harm, so how to prevent this from happening?

The reasons:

First of all, cryovials cannot be directly placed in the liquid phase of liquid nitrogen for preservation. Because the material of the tube body and the cap of the common cryovials are different, the rates of thermal expansion and contraction during freezing are also different. If you put the cryovial directly into the liquid phase, you may allow liquid nitrogen to flow into the tube. When resuscitating the sample next time, put the cryogenic-vials into a water bath at 37°C, the liquid nitrogen in the tube quickly vaporized and expanded, but the gas could not escape from the tube in time, which caused the cryopreservation tube to explode.

How to avoid:

1. Do not store cryovials directly in the liquid phase, but in the gas phase. Or just freeze it directly in the refrigerator. Remember not to place it directly below the surface of the liquid nitrogen.

2. Use internal rotation cryotubes.

Of course, even internally rotated cryotubes cannot be placed directly into the liquid phase, but internally rotated cryotubes have better low-temperature tolerance than externally rotated caps, which can reduce the possibility of explosion and are relatively safer. The external rotation cryotube is actually designed for mechanical freezing, so it is not suitable for liquid nitrogen storage.

3. So what should you do if you really need to store it in liquid phase? In response to this problem, there are actually cryopreservation tube sleeves specially designed for this purpose, which can be used to seal the cryopreservation tube and then place it in the liquid phase. Of course, you can also use sealing film, medical tape, etc. to seal it, so that there will be basically no explosion.