calculating the number of cells to freeze down
Posted 24 November 2011 - 05:29 AM
i desparately need your help with the following.
I need to start growth curve experiments that will run over 7 days, my supervisor wants me to seed 1x105 cells in 20ml of medium in each T75 flask and im struggling to calculate
i need to freeze down SK-N-SH cells. the final concerntration of cells should be 3x106. the total number of cells i have in 20ml is 3.14x107.
Posted 24 November 2011 - 11:33 AM
If so: if 20ml contains 3.14x107 cells, then how much cells are there in 1ml? And how much you need to take to end up with 1x105 cells ?
3.14x107cells/20ml = 1.570.000cells/ml ==> how much you need to take to have 100.000 ? Cleary 1ml still contains too many cells...
If you don't know it, then ask it! Better to ask and look foolish to some than not ask and stay stupid.
Posted 07 January 2012 - 09:30 AM
1) Spin down my SK-N-SH cells and resuspend in 1ml of media. that 1ml should contain 3.14x10^7 cells.
2) Aliquot 100 microL into a cyrovial and top-up the desire amount of media and cyro preservatives for freezing.
- This would have ~3 million cells.
3) To get 1x10^5 in 20ml, just use this formula:
Initial concentration(M1) X Initial Volume (V1) = Final Concentration (M2) X Final Volume (V2)
=> Initial Volume (V1) = [0.1 X 20ml]/31.4 = ~0.06369ml or 63.69 microL
Simple calculations hehe