Woohoo, it's the Bank holiday weekend!

I've topped up our liquid nitrogen storage tank to keep our cells at a cool -196C while I'm out in the sunshine this weekend.  At this temperature, metabolic activity ceases and in theory the cells can be stored indefinitely.  It's really important that cells are stored in the vapour phase of a nitrogen store and not in the liquid, for 3 reasons: First, safety: small droplets of liquid can enter the threads of the vial cap, and cause the vial to explode upon thawing, especially in older designs of cryovials.  Second, to avoid contamination: it may be hard to imagine, but cases have been documented of mycoplasma contamination spreading between vials stored in the liquid phase.  And third: cost.  Liquid nitrogen is a major expense for cell culture labs.Why fill the storage vessel to the brim with liquid nitrogen, when using only a small percentage of the volume would actually do a better job?....
OK, on that note I will sign off for the week.  You all have a fab bank holiday weekend, and we'll catch up next week with more cell culture info and tips!  Cheers, Cellwyn.