The surface conductance of red blood cells and platelets is modulated by the cell membrane potential

Dielectrophoretic analysis of cell electrical properties via the Clausius–Mossotti model has been widely used to estimate values of the membrane conductance, membrane capacitance and cytoplasm conductivity of cells. However, although the latter two values produced by this method compare well to those acquired by other electrophysiological methods, the membrane conductance is often substantially larger than that acquired by methods such as patch clamp. In this paper, the electrical properties of red blood cells (RBC) are analysed at two conductivities and following membrane-altering treatments, to develop a mathematical model of membrane conductance. Results suggest that the RBC “membrane conductance” term is primarily dominated by surface conduction, comprising an element related to medium conductivity augmented by conduction in the electrical double layer, which is in turn altered by the cell membrane potential. Validation of the relationship between membrane potential and membrane conductance was performed using platelets, where a similar relationship was observed. This sheds new light on the origin and significance of the membrane conductance term and explains for the first time phenomena of alterations in the parameter counter to changes in membrane potential or cytoplasm conductivity.