I've been having problems with SW480 cells dying or lifting off after PBS washing or sample treatment.

Normally I dispense PBS or sample on the left side of the well, and I noticed that only the cells on the left side or left edge of the well shrink/lift off/die. SO i thought maybe it's the pressure from the fluid flow that's making the cells die and I've been trying my best to minimize this by extending seeding hours (24 to 48hrs) to make sure cells are firmly attached and dispensing liquids really slowly to minimize fluid flow, but it doesn't seem work well.

Are there any better ways to prevent this other than using coated wells? Thanks :)