Cryopreservation of MSC at lower cell density - (Feb/04/2013 )
Most publications suggest freezing mesenchymal stem cells at about 10^6 cells/ml of cryopreservative solution.
If I have very low cell numbers, my inclination is to store at below 10^6 cells/ml to ensure I'm not working with tiny volumes.
I have done a quick literature search & can't see anything - does anyone have a link to anything published about freezing at lower cell density?
I don't work with stem cells, so this should be read with caution - many cells lines will survive well if frozen at lower densities, however, it does pay, when reviving the cells, to take this lower density into account and adjust the area onto which they are plated. For example, seed into a t-25 instead of a t-75.
I don't work with MSCs either, but with a different kind of stem cells. I'd say it should be fine to freeze at lower density and I fully agree with bob that when you thaw your cells, you should plate them in a small flask first. Also take care to keep the time for thawing as short as possible and if they don't really seem to grow well in the first few days, just leaving them alone in the incubator for a while (lower frequency of medium exchange etc.) might be helpful.