edge effect in cell-based assays - (Oct/28/2004 )

Hi

I use 96/48-well plates for adherent cell culture, with about 25% confluency at seeding. I noticed that the cell distribution WITHIN each well is not uniform. There are more cells along the rim than at the center. I am not sure about the reason and couldn't think of a way to reduce this edge effect. Uniformity of cell seeding is very critical for me since I will be analyzing the wells individually by imaging to look at the effect of different compounds on cell growth.

Can somebody help me out? Thanks!

Kalyani.

Hi Kalyani,

The edge effect cannot be avoided especially with 96well plate because the liquid tends to take a shap that has the least surface area so it will hang to the side wall and that is why there are fewer cells in the center. Try using plates with bigger wells if possible.

Try using more volume of media and adjust your seeding concentration accordingly.

Thanks for the responses. I found this tech report which says that, pre-incubating the cell-seeded wells at room temperature in air before keeping it in the incubator can reduce the uneven distribution. weird, eh?

http://www.ingentaconnect.com/searching/Ex...000005/art00009

Hello, I read that paper as well, but I think the edge effect that is mentioned in this paper was more about the difference of cell amount in different wells accross the plate, whereas your concern is more within the well.

Yes, zienpiggie is right. There are two types of edge effect, one is within the well, the other is within the plate. All edge wells tend to behave differently from inside wells (due to medium evaporation?). I usually don't use those wells for treatment. Also I always place the plates in a dump box.