Cryovial with partial membrane sealing can prevent liquid nitrogen penetration in submerged storage

Cryopreservation is one of the fundamental techniques in life science. To preserve the viability of cells and tissues, many researchers use plastic cryogenic vials and immerse them into liquid nitrogen for long-term storage. However, the non-sterile liquid nitrogen usually infiltrates into the vials and may cause a high rate of microbial contamination, and even some explosive incidents upon retrieval. To prevent these drawbacks while retaining the benefit of constant ultra-low temperature in submerged liquid nitrogen, we used a heat-sealable membrane to cover the upper portion of vials. After heat-sealing, the vials were completely free of liquid nitrogen penetration in the submerging test. Moreover, the sealing process did not affect the cell viability. This modified protocol provides an easy and efficient tool to ensure the integrity of biospecimens in long-term storage without interfering with existing cryobox storage systems.