Rapid separation of cells at unit gravity.

An apparatus is described for the rapid separation of cells at unit gravity. The apparatus is filled with a discontinuous density gradient, followed by the sample and then an overlay. The sedimentation chamber is turned from a vertical to a horizontal position before sedimentation takes place in order, (a) to form a continuous gradient out of the discontinuous gradient and, (b) to reduce the time required for the separation. After the sedimentation is completed the chamber is returned to a vertical position and the gradient fractionated by hydrostatic pressure using a newly developed floating device. The usefulness of the method is illustrated by the separation of leukemia cells in different phases of the life cycle.