Liquid nitrogen, abbreviated as LN2, is nitrogen gas that has been cooled and compressed to its liquid state at -195.8°C at atmospheric pressure. It is colourless, odourless, non-toxic, and chemically inert under normal conditions, making it the preferred cryogenic medium across IVF laboratories, sperm banks, biobanks, research institutions, and NHS fertility units throughout the UK.
The reason LN2 dominates cryogenic storage is straightforward: it maintains temperatures far below the critical biological threshold of approximately -130°C, the point at which cellular metabolism and degradation effectively stop. Below this temperature, biological material enters a state of suspended animation, meaning embryos, oocytes, and sperm samples stored correctly in liquid nitrogen can remain viable for extended periods.
LN2 is produced industrially through fractional distillation of liquid air, a process that separates atmospheric gases by their different boiling points. Nitrogen constitutes approximately 78 per cent of atmospheric air, making it an abundant and cost-effective cryogenic medium compared with alternatives such as liquid helium.
In an IVF or andrology setting, LN2 is stored in vacuum-insulated vessels known as dewars. These range from compact 2-litre benchtop units to large 500-litre bulk tanks, depending on the volume of biological material being stored and the frequency of access required. The choice of storage vessel directly affects LN2 consumption, evaporation rate, and ultimately the safety margin available before a temperature excursion becomes a risk.
Cryolab has supplied LN2 storage vessels to UK fertility clinics, NHS trusts, and research laboratories for over 40 years. Browse the full range of storage vessels at cryolab.co.uk/product-category/storage-vessels/.
