Liquid nitrogen sits at -195.8°C at atmospheric pressure, and that precise temperature is not an arbitrary specification. It sits at the heart of every IVF laboratory’s cryogenic storage programme for one precise biological reason. You will often see the figure quoted as minus 196°C, which is the same number rounded, so the two are used interchangeably across the sector.
At temperatures below approximately -130°C, biological materials enter what scientists call the glassy state. At this point, molecular motion effectively ceases. Chemical reactions that would normally degrade cellular structures stop entirely. The cell does not die, it does not deteriorate – it simply waits, in a state of biological suspension, for as long as the temperature holds.
The problem with trying to store samples at -80°C (the temperature of a standard laboratory freezer) is that molecular motion has not stopped. Ice recrystallisation continues slowly, enzyme activity persists, and oxidative damage accumulates. Over months or years, samples degrade. At -195.8°C, none of this happens.
Think of it this way: -80°C slows biology down. -195.8°C effectively stops it.
For embryos, oocytes and sperm – materials that can spend anywhere from a few months to 55 years in storage under current UK legislation – this distinction is the difference between a viable sample and a compromised one. A blastocyst stored correctly has the same biological age it had when it was frozen. That is the extraordinary reality of liquid nitrogen cryopreservation.
This is why the quality of your storage vessel matters so much. The CryoNest storage vessels used across UK IVF laboratories are designed to maintain performance at -195.8°C with hold times that provide a genuine safety margin. For advice on the right vessel, contact Cryolab or use CryoGPT.
