Embryos are stored in liquid nitrogen at approximately minus 196 degrees Celsius, the temperature at which all biological activity effectively stops. Held at this point, embryos can remain viable for many years, even decades, with no measurable deterioration, which is why frozen embryo transfer is so dependable. As the HFEA explains in its guidance on embryo freezing, samples are held either fully submerged in liquid nitrogen or in the cold nitrogen vapour just above it.
The vessels used for this are vacuum-insulated to slow the natural evaporation of nitrogen and keep the internal temperature stable. Maintaining that temperature without interruption is the single most important factor in safe long-term storage, since even brief warming can damage delicate cells. Clinics therefore rely on well-designed containers and disciplined monitoring of nitrogen levels. Cryolab supplies CryoNest LN2 storage vessels and storage accessories engineered for stable, low-loss performance in busy laboratories.
