ELECTRIC-FIELD-INDUCED TRANSMEMBRANE POTENTIAL DEPENDS ON CELL-DENSITY AND ORGANIZATION

Electrochemotherapy is a novel technique to enhance the delivery of ch emotherapeutic drugs into tumor cells. In this procedure, electric pul ses are delivered to cancerous cells, which induce membrane permeabili zation, to facilitate the passage of cytotoxic drugs through the cell membrane. This study examines how electric fields interact with and po larize a system of cells. Specifically, we consider how cell density a nd organization impact on induced cell transmembrane potential due to an external electric field. First, in an infinite volume of spherical cells, we examined how cell packing density impacts on induced transme mbrane potential. With high cell density, we found that maximum induce d transmembrane potential is suppressed and that the transmembrane pot ential distribution is altered. Second, we considered how orientation of cell sheets and strands, relative to the applied field, affects ind uced transmembrane potential. Cells that are parallel to the field dir ection suppress induced transmembrane potential, and those that lie pe rpendicular to the applied field potentiate its effect. Generally, we found that both cell density and cell organization are very important in determining the induced transmembrane potential resulting from an a pplied electric field.