Separation of human breast cancer cells from blood by differential dielectric affinity.

Electrorotation measurements were used to demonstrate that the dielectric properties of the metastatic human breast cancer cell line MDA231 were significantly different from those of erythrocytes and T lymphocytes. These dielectric differences were exploited to separate the cancer cells from normal blood cells by appropriately balancing the hydrodynamic and dielectrophoretic forces acting on the cells within a dielectric affinity column containing a microelectrode array. The operational criteria for successful particle separation in such a column are analyzed and our findings indicate that the dielectric affinity technique may prove useful in a wide variety of cell separation and characterization applications.