The applicability of freeze-thaw Percoll gradients to whole-cell isopycnic fractionations: preliminary results.

The freeze-thaw method of gradient generation, using Percoll as the density medium, is shown to be adaptable for the isopycnic sedimentation of live whole cells. Methods of controlling gradient profiles are examined with preliminary evidence showing that three types of cells brought to isopycnic equilibrium in these gradients and recovered from them retain satisfactory levels of several vital functions.