Bioelectrochemistty and Bioenergetics, 15 (1986) 229-241 A section of J. Electroanal. Chew., and constituting Vol. 211 (1986) Elsevier Sequoia S.A., Lausanne - Printed in The Netherlands 229 zyxwvutsrqpo 852 - CONDUCTION ONSET CRITERIA FOR TRANSIENT AQUEOUS PORES AND REVERSIBLE ELECTRICAL BREAKDOWN IN BILAYER MEMBRANES * JAMES C. WEAVER ** and ROBERT A. MINTZER *** Harvard-MIT Division of Health Sciences and Technology, 2OA-128, MIT, Cambridge, MA 02139 (U.S.A.) HA0 LING * Departments of Electrical Engineering and Computer Science, and Physics, MIT, Cambridge, MA 02139 (U.S.A.) STEVEN R. SLOAN ** Departments of Electrical Engineering and Computer Science, and Biology, MIT, Cambridge, MA 02139 (U.S.A.) (Manuscript received June 18th 1985) SUMMARY As in the preceding paper, the hypothesis is adopted that a large number of transient aqueous pores can be continually present in a bilayer membrane. Here approximate criteria are obtained for the onset of ionic conduction through such pores. The pore radius, r, and transmembrane potential, U, are both important parameters. Small pores do not conduct significantly for small values of CJ, which is consistent with the well-known high electrical resistance of artificial bilayer membranes at low transmembrane potentials. In contrast, large pores conduct readily even at low transmembrane potentials. This allows a qualitative description of reversible electrical breakdown (REB). REB is the sudden, dramatic increase in both conductance and permeability which occurs when large transmembrane potentials of short duration are experienced by the membrane. In the following paper the conduction criteria are used in a fully quantitative theory of REB. INTRODUCTION zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA The dramatic phenomenon of reversible electrical breakdown (REB) has been amply demonstrated experimentally by others in a variety of artificial bilayer * Contribution presented at the 8th International Symposium on Bioelectrochemistry and Bioenergetics, Bologna, June 24th-29th 1985. ** To whom correspondence should be addressed. *** Present address: Department of Physics, University of Chicago, Chicago, IL, U.S.A. * Present address: Department of Electrical Engineering, University of Illinois, Urbana, IL, U.S.A. ** Present address: Medical School, New York University, New York, NY, U.S.A. 0302-4598/86/$03.50 0 1986 Elsevier Sequoia S.A.