DIFFERENTIAL DIELECTRIC BEHAVIOR OF THE PLASMA MEMBRANE IN MOUSE FIBROBLASTS AND HUMAN EMBRYO KIDNEY CELLS

The dielectric features of “native” human embryo kidney cells (HEK293) and mouse fibroblasts (3T6) were investigated by electrorotation. The specific dielectric parameters Capacitance (C) and Conductance (G) exhibit a significant difference between the two cell lines. In the case of the human one, both parameters result in an increase by one order of magnitude, in the early stage of the culture. This drastic difference with respect to 3T6 cells, tends to disappear as the culture time proceeds. Parameter C is directly related to the membrane structure, while G mainly derives from the active and passive ion flux. The variation of these parameters is discussed in terms of an intrinsic functional/structural difference of the cell membrane in the two cell lines. Finally, the phenomenon is not ascribable to membrane mal-functions, as evidenced by cellular/molecular assays.