Reversible Electrical Breakdown of Lipid Bilayer Membranes
Charge pulse experiments were performed with lipid bilayer membranes from oxidized cholesterol/n-decane at relatively high voltages (several hundred mV). The membranes show an irreversible mechanical rupture if the membrane is charged to voltages in the order of 300 mV. In the case of the mechanical rupture the Voltage across the membrane needs about 50 μs-200 μs to decay completely to zero. At much higher voltages, applied to the membrane by charge pulses of about 500 ns duration, a decrease of the specific resistance of the membranes by nine orders of magnitude is observed (from 108Ωcm2 to 0.1Ωcm2) without a mechanical rupture of the lipid bilayer membrane. Due to the high conductance increase (breakdown) of the bilayer it is not possible to charge the membrane to a larger value than the critical potential difference Vc. For 1 M alkali ion chlorides V c was about 1 V. The temperature dependence of the electrical breakdown voltage Vc is comparable to that being observed with cell membranes . Vc decreases between 2°C and 48°C from 1.5 V to 0.6 V in the presence of 1 M KC1.