time course experiment, treat them all at once, or harvest them all at once. - (May/08/2010 )
I am planning to do a time course experiment that will include 30 min, 1h, 2 h, 4h and 12 h incubation time of my treatments with my cells. I am just wondering if it is more acceptable to treat the cells all at the same time, and then harvest the cells for further analysis at the pre-determined termination time, or would it be ok to being treating cells at 12h, 4h, 2h,1h and 30 minute prior to termination time then harvest them all at the same time?
It depends on the experiment, but in most cases, no on cares which. Do the one that you think will generate the most reliable, consistent results.
Consider stuff like this:
"If I choose to harvest all at once, while I wait to treat the '30' minute sample, will the cell count increase and skew my final results?"
"If I treat all my samples at once, what will happen to my 30 minute sample during the 12 hours that follow?"
I prefer to treat all of the samples at the same time so that each plate/flask/whatever contains the same number of cells in the same conditions (ie fresh media).
Also be aware that you sampling proceedure may take longer than 30 min, so this may affect how you do your experiment.