exponential growth = or ^= 50-80% confluence? - (Apr/14/2006 )

some cells like immortalized normal epithelial cell and primary epithelial cell still keep their growing characters such as contact inhibit well. so when we culture them, we always want them to be at exponential growing phase. how to judge this?

the growing speed or confluence?

I would say both, for sure

when my primary cells are happy, they grow at a fairly predictable rate (minor variation between lots) and reach confluence in a fairly predictable time-frame, based on splitting ratio

of course, this only applies applies till they reach senesence, being primary cells...that's how you know; the only change is that they start growing veerrryyyy sllloooowwwwwllllyyyyyy...but are mycoplasma negative...and it also usually occurs around the same passage