 Some cells in culture grow better on surfaces coated with positive charge like poly-L-lysine or polyornithine or Alcian blue.Alcian blue coated surfaces hold onto the negatively charge glycocalyx so tight that it can even be used to cover a layer of cells and then float it up to peel off the roof ("unroofing") to study the cytoplasmic side of the plasma membrane.Alcian Blue has been used as a gelling agent for lubricating fluids likely due to the stacking properties of this macrocylic aromatic compound.