Membrane pores—From biology to track-etched membranes

Abstract

Flow of ions through narrow pores, either induced in biological membranes or created in synthetic membrane filters, exhibits, under appropriate conditions: 1) rapid switching of ion current between high and low conducting states; 2) selectivity between different ions; 3) inhibition by protons or divalent cations with an order of efficacy usually H⁺ >Zn²⁺>Ca²⁺ >Mg²⁺. It seems reasonable to conclude that these common properties arise from a common cause-the nature of the flow of ions close to a charged surface.