Exploding cryovials - (Sep/08/2009 )

I normally store our frozen cells in the vapor phase of the liquid nitrogen tank but some months back, it was inadvertently filled to the top by another lab member. Since then, I have experienced that about 1 in every 2 vials I thaw is exploding. These are primary human cells and we just can't afford to waste that many samples and as my screen name implies, I've also become a bit of a nervous wreck every time I have to thaw cells (I do wear proper PPE so am not really worried about being hurt but I'm a person who hates thunder, fireworks and gunshots and this rates right up there on that scale!). I do let them vent in the safety hood for a few minutes before transferring to the water bath but the odd thing is that they seem to be exploding either when I touch them to transfer them or when I place them in the water bath (and I was always taught to let them vent first b/c that is when they will explode if they are going to do it). Does anyone have any other suggestions as to what I might try? I read something about thawing on dry ice - is this likely to work and if so, how long do I leave them on dry ice? I can't ask anyone else to do it as I'm the only lonely soul here. Thanks in advance - unless I can figure out a better solution my cell culture days may be numbered b/c I am way too stressed over this thawing process.

Hi,

I experienced a similiar problem when I first started working with frozen cell cryovials. Unfortunately the only thing I could suggest to you is to very quickly take your vial from storage and transfer it very quick to a biological safety cabinet and then unscrew the cryovial lid off to avoid pressure build up. This ought to stop the cap from exploding off and wasting the vial contents. Let me know if this works.

There are a number of solutions possible:

1) Try a different brand of cryovial - we use cryo-s from Nunc (I think). It will help if they have a silicone gasket and are not over-tightened.
2) loosen the cap slightly immediately after removal from the LN2
3) put the tube inside one of the products that are designed to stop this happening (cryoflex from Nunc is the product that springs to mind, there will be others)

Never thaw the samples completely on dry ice, ice (or preferably dry ice) should only be used to transfer the cells from the LN2 to the waterbath where you are thawing the cells. The general rule for cells is freeze slow, thaw fast.

Dry ice is also warm enough (-86˚C) that the LN2 (-196˚C) will evaporate almost instantly.