When cultured in T25 or T75 TC-treated/untreated flasks, majority of the cells stay in suspension. However, when I culture them in untreated 6/12/24/96-well plates, they stick to the bottom of the dish within a few minutes of seeding. I also tried culturing them on ultra-low attachment dishes coted with hydrogel (which is supposed to prevent cell attachment) and they stick to these as well. What is happening here? Is it only electrostatic interactions?