Dear Indoubt,Growing suspension cells: to stir or not to stir?
This depends on the cell line. You need to know if your cells stick to the flask or form large clumps without agitation.
If they don't stick (especially to untreated flasks), then you do not need shaking/stirring for small volumes of suspension cells (<50 ml). Just place into a standard 5% CO2 incubator on a slant to stop media getting into the lid area of the flask.
If they do stick, you can place a rotating shaker into the incubator (most incubators have a hole in the back for the cord) and then gently shake the cells while incubating. NB: gently means you don't want frothing of the media.
If however, you require larger volumes and have spinner flasks, then you'll need the spinner plate in the incubator and again, gently spin the cells.To feed suspension cells:
you will need to centrifuge them to remove the spent media and replace with fresh. Centrifuge speed is dependent on your cells but ~ 650 x g is fairly typical.
You can "split" the suspension cells without centrifuging by counting the main culture and then diluting the required volume of culture in fresh medium.
with regards to your last question ...
I can't help you there, sorry.