Effect of X-rays on the Electrical Conductance of Phospholipid Bilayer Membranes

Abstract

A LONG-STANDING hypothesis suggests that a significant contribution to the radiobiological effects of ionizing radiations comes from the damage they cause to cell membranes¹. The production in this way of massive damage to the membranes—allowing the movement of macromolecules across them—would be of considerable importance, but a smaller change affecting only their permeability to simple electrolytes could also have noticeable biological effects. We have studied the possibility of the latter phenomenon using a system recently introduced as a partial model of the cell membrane. The model membranes are optically black structures formed of phospholipid dissolved in a hydrocarbon; they can be made 1 mm² or more in area, are probably two molecules thick², are stable for several hours and have readily measurable electrical characteristics^2,3.