We use 1% polyethylenimine to stick down fixed yeast cells for
immunofluorescence. The cells really stay stuck down all the way
through the entire process. The only problem is that you may put
down too many cells if you are used to using polylysine. The
concentration of cells on the slide at the beginning should be the
same as you need to see at the end of the process. Definitely don't
put down more cells than you need, just to account for loss of cells.
Protocol: Filter 1% polyethylenimine through 0.22 micron filter.
Place drop in well of slide. Wait 1-2 min. Rinse off with distilled
water and air dry. Add cells and let settle for 5-10 minutes (in a
moist chamber). Continue as usual.