Wall effects in sucrose density gradient centrifugation of viruses

The depletion of sedimenting particles to be expected from wall effects in the course of sucrose gradient centrifugation, was computed for various types of swing-out rotors on the assumption that particles hitting the tube wall are lost from the gradient. This assumption was roughly verified for heat-denatured, but not for native poliovirus. Tween 20 reduced the depletion, and prevented tight sticking of heat-denatured virus particles to tube walls.