FICOLL has the follwing key advantages: Proven medium for density gradient centrifugation. -Does not penetrate biological membranes -High density solution of low viscosity and low osmotic pressure -Preserves functional and morphological integrity. -Useful for separating cells which are sensitive to centrifugation and for separating cells of similar density but different size (under conditions of sedimentation at unit gravity). -Can be used in other applications such as electrophoresis, hybridization cryopreservation and as a hapten carrier.