Laboratory frozen samples generally use low-temperature refrigerators and liquid nitrogen tanks.
The low-temperature refrigerator relies on electricity to cool down, and the temperature fluctuation of the sample is slow to recover, which is more suitable for samples that are not taken very often;
The liquid nitrogen tank has a fast cooling speed and small temperature fluctuation, especially the vapour phase ln2 storage tank, which has excellent temperature uniformity and stability, and can freeze large quantities of biological samples for a long time.
How long is this long term?
Theoretically, the vapour phase ln2 storage tank can store samples forever!
Of course, the premise is the uninterrupted supply of liquid nitrogen, regardless of the service life of the container, without any interference factors!
From the actual point of view, it is necessary to combine its own usage, including liquid nitrogen supply, service life, and its own needs.
For specific storage samples, please refer to liquid nitrogen:
We know that samples stored under -196°C liquid nitrogen can still maintain activity above 95-98% after 10 or 20 years.
The vapour phase ln2 storage tank with liquid nitrogen as the cold source, as long as the liquid nitrogen is always supplied, can achieve the same freezing storage life as liquid nitrogen.
This is also the reason why stem cells, embryos, blood and other samples are frozen in vapour phase ln2 storage tanks, which can be stored for decades without affecting the use activity.