Chronopotentiometric studies of electroporation of bilayer lipid membranes

Abstract

The constant-intensity current chronopotentiometric measurements of egg yolk phosphatidylcholine bilayer membranes (BLM) are presented. It is demonstrated that a constant-intensity current flowing through the bilayer membranes generates the pores in their structures. For the current intensity from 0.1 to 2.0 nA, the generated pores open and close cyclically. The frequency of oscillations depends on the current intensity: the higher current intensity, the higher frequency of pore oscillations. It is suggested that the presented method may allow to create one pore in BLM and to observe its dynamical behaviour. Based on chronopotentiometric curves, a method of pore conductance calculations is presented. It is demonstrated that the value of obtained conductance can be applied for pore diameter estimation. The hypothetical application of constant-current method as a biotechnological tool for selective and controlled incorporation of molecules into microorganisms is discussed.

Evidence of Conducting Hydrophobic Nanopores Across Membranes in Response to an Electric Field

“…46 The measuring system 47 was comprised of four Ag-AgCl electrodes (2 current and 2 reference electrodes) and consisted of two modules allowing the measurement of the lipid bilayer capacitance and the voltage across the bilayer, and a potentiostat-galvanostat for the current control. The specific membrane (bilayer) capacitance (c BLM ) normalized to the surface area of the bilayer was measured with capacitance to period conversion.…”

Simulation of electroporated cell by chronopotentiometry

“…This effect is a sign of an electropore formation. Estimation of the electropore diameter indicates that usually a single nanopore is formed [21]. Short breaks in current supply do not let the electropore reseal [18].…”

“…Electropore conductance G p at any selected point (Fig. 4) was calculated by the method described previously [21] as:…”

“…This method takes into account the resistance of the membranes without the electropore and changes in the membrane capacitance caused by the membrane potential [21]. The electropore diameter was calculated based on the following assumptions: (a) the shape of the electropore is cylindrical, (b) the electropore is filled with the same electrolyte as a bulk electrolyte, (c) the change in the temperature inside the electropore, resulting from the current flow, did not significantly change the electropore conductance.…”

A System for the Determination of Planar Lipid Bilayer Breakdown Voltage and Its Applications

“…It is believed that during these kinds of measurements, the lipid bilayer is more stable due to less voltage stress [27], [30]; therefore, small changes in the membrane structure can also be observed. Scalas et al [31], for example, reported on the time course of voltage fluctuations that followed an increase of the membrane conductance due to the opening and closing of hydrophilic pores [28], [31], [40].…”