Changes in electric properties of human breast cancer cells.

Studies of the electrical surface properties of biological cells have provided fundamental knowledge about the cell surface. The change in biological functions of cells may affect the surface properties and can be detected by electrokinetic measurements. The surface density of fibroblasts and breast cancer cells (MDA-MB-231 and MCF-7) as a function of pH was measured by electrophoresis. The interaction between solution ions and the breast cancer cell or fibroblast surface was described by a four-component equilibrium model. The agreement between the experimental and theoretical charge variation curves of the breast cancer cells and fibroblasts was good at pH 2.5-9. The extent of fibroblast and breast cancer cell lipid peroxidation was estimated by HPLC measurement of the malondialdehyde level. The acid (C(TA)) and basic (C(TB)) functional group concentrations and the average association constant with hydroxyl (K(BOH)) ions values of the breast cancer cell membranes were higher than in normal cells, while the average association constant with hydrogen (K(AH)) value was smaller. The level of lipid peroxidation products was higher in breast cancer cells than in normal cells.