Pipetting stress on cells - (Nov/14/2007 )
Does anyone have any info on the shear stress that cells experience when being pipetted for plating (i.e. 10, 20, 200, 1000 ul pipet tips)? Or more general any effects on cells during pipetting. Thanks.
Haven't thought about that, but I have been using 200 ul pipet tips to seed cells in 96 well plates on a routine basis.
My PI is picky about using a P-1000 for plating cells for primary cells. I use P-100 for all cell lines.
I think it does not give that much harm to the cells if you do not pipet them over and over otherwise any cells can grow on an agar plate after incubating them in LB.
It is well known that TRITURATION (pipetting a cell suspension up and down), can cause cell damage. The longer and more vigorous the trituartion, the more serious the effects.
This can be minimised by reducing trituartion to a minimum, and by cutting the tips off pipette tips. This effectively widens the bore and reduces damage.
Look in the literature : Mol.Reprod. Dev. 74 pages 1287-1294 2007 Rappolee et al. They looked at damage to embryo's via increased trituration. Transient changes in protein levels and mRNA were observed. However the long term effects were minimal........this at a shear stress level of 1.2 dynes/cm2.
Depends on the speed you are drawing and expelling and the opening size of the pipette. Shearing of cells can happen.