You freeze mammalian cells by dunking them in LN2? I’ve… never heard of anyone do that. I’ve always put them in either a Mr. Frosty or a styrofoam conical holder (makeshift Mr. Frosty)
Comment on Sup, guise.
Beryl@jlai.lu 2 months ago
You’d actually want to freeze them as fast as possible, to prevent the growth of large ice crystals that would tear the cell apart. That’s why you do it by dunking them in liquid nitrogen. But yeah frozen bacteria are basically immortal.
Contramuffin@lemmy.world 2 months ago
SydBa@sh.itjust.works 2 months ago
I really enjoy that the actual name for a scientific too is Mr. Frosty.
Beryl@jlai.lu 2 months ago
I guess I forgot about the first part of the meme and was talking bacteria, sorry. For eucaryotic cells sure you’d take your time in a -80°C first.
Swedneck@discuss.tchncs.de 2 months ago
i for one also think it’s most intuitive to assume you’re talking about the last part of the meme when it’s not specified in the comment
phdepressed@sh.itjust.works 2 months ago
No you add DMSO (5-10%) and freeze slowly. Using a Mr frosty or similar. Otherwise a few hours at -20, then -80, before the LN2.
Just chucking in LN2 is going to have terrible recovery. That might have been done with HeLa way back when but certainly isn’t standard anymore.
Beryl@jlai.lu 2 months ago
I mean obviously you’d use DMSO or glycerol, I just didn’t want to get too technical. That being said I’ve always snap-frozen bacteria with LN2 and it worked just fine. Now for eucaryotic cells, sure, you’d want to go slow.