My work informed us of a 6 hours power cut to the whole building in a couple of months time in April. We have thin tissue cryosections (for immunofluorescence staining) and aliquots of primary antibodies at -20 and fresh tissues at -80. Without opening the doors for those 6 hours, what temperature would the freezers be able to keep? I would expect adverse effect on the above contents. We did experience some quality deterioration of tissue in immunofluorescence experiments, which is likely due to a previous couple of hours power cut in August (hottest time of the year, again due to building/installation work). Any insights/experience/advice are very welcome and appreciated.
First of all, I am very sorry for the problems you have had. The average heating rate of the freezer will depend on the specific model, but it is usually between 1ºC and 8ºC per minute. In the datasheet of your freezer should appear a parameter that is "warmup time" that in the case of the ultrafreezers is the time to go from -80ºC to -50ºC. My biggest concern would be the fresh material. Although with some antibodies there may be problems, I have never had any. Anyway it will also depend on whether they contain a cryoprotectant or not (glycerol). I would suggest adding a glycerol to the antibodies (50:50), in case they do not contain it.
If you have room in the freezers, you can add blocks of dry ice to prevent the temperature from increasing. Put the blocks as high as possible without contacting the walls of the freezer.
You can also slowly increase the thermal bulk of your freezers by adding periodically frozen gel packs in the week leading up to the power outage. This will slow the warming without the complications of working with dry ice.
Hi Lan,
I have faced similar kind of issues during my PhD, tissue sections stored properly in OCT did not showed much alterations on immunostaining and similarly no changes were observed in in protein expression also when fresh tissue samples were lysed in RIPA buffer.. Maximal you can see a downfall of upto -30 degrees, in my case our -80 use to go down till 47 degrees, but fortunately our samples were fine and worked well. In general samples usually start degrading if samples have been stored at lesser than -20 degrees for a longer period of time, and from rapid freeze thaw. However, I would like to let you know that antibodies are very sensitive and they may degrade. Best is to store your antibody at some alternative place.
I hope all goes well.
Best,
Dr. Jaspreet
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