Is cell density (% confluence) and passage number important considerations?
Yes. Cell density will affect transfection performance. For example, Lipofectamine™ 2000 provides excellent transfection performance at a confluence of 90% or greater, while slight toxicity may be observed at confluencies lower than this. We recommend using Optifect™ for cell densities <70% confluence. Passage number may affect transfection experiments. We recommend splitting and plating cells consistently. Excessive numbers of passages may decrease transfection performance. If transfection performance declines and cells have been in culture for a long time or excessively/improperly passaged, we recommend that you restart your cultures with a new vial of cells from liquid nitrogen.
