Detection of differences in surface-charge-associated properties of cells by partition in two-polymer aqueous phase systems.

Abstract

WHEN aqueous solutions of two polymers are mixed in certain proportions they may form two-phase systems1,2 which can be buffered and used to partition and separate cells, particles and macromolecules by countercurrent distribution (CCD). Partition generally depends on polymer composition and concentration, the ionic composition and the charge sign of the material being partitioned. Such systems have been used to separate erythrocytes from white cells and erythrocytes on the basis of age. Changes in the surface properties of cells resulting from enzyme treatment or storage have also been demonstrated by this means3. Higher cell partition often accompanies increasing electrophoretic mobility which suggests that surface charge may be an important factor in partitioning4–6. An apparent exception to this is the increased partition of stored human erythrocytes as compared with fresh7, as opposed to the mean electrophoretic mobility of both cell populations which remain identical8.