Electromechanical stress produced in the plasma membranes of suspended cells by applied electrical fields

We analyze the electrical and mechanical stress in the bounding membrane of a cell (or vesicle) in suspension which is deformed by an external applied field. The membrane is treated as a thin, elastic, initially spherical, dielectric shell and the analysis is valid for frequencies less than the reciprocal of the charging time (i.e. less than MHz), or for constant fields. A complete analytic solution is obtained, and expressions are given which relate the deformation, the surface tension and the transmembrane potential difference to the applied field. We show that mechanical tensions in the range which lyse membranes are induced at values of the external field which are of the same order as those which are reported to lyse the plasma membranes of cells in suspension.