K.H. Tantawi
University of Tennessee at Chattanooga,
United States
Keywords: lipid bilayer membranes, phospholipids, electrochemical impedance spectroscopy
Summary:
In this work we conducted a molecular dynamic simulation coupled with results of an experimental electrochemical impedance spectroscopy to determine the dielectric properties of phospholipid bilayer membranes formed from phosphatidylserine. The MD simulation shows that the lipid bilayer membrane (LBM) remained intact with almost no observed effect after applying an electric potential of up to 1000 mV across it for the first 100 ps. Formation and recombination of nanopores and lipid flipping were observed at 900 mV and 1000 mV after less than 300 ps of application of the electric potential. The Electrochemical Impedance Spectra of phosphatidylserine show that a lipid bilayer membrane formed from this phospholipid has an average electrical specific resistance of 653 Ω.cm2 (equivalent to a resistivity of 13 MΩ.m ) and an average capacitance of 0.765 µF/cm2 . A wide range of values of the electrical resistivity are reported in literature for bilayer membranes formed from other phospholipids, that vary up to six orders of magnitude in range. The value reported here is close to the resistivity of cellular membranes and is approximately within one order of magnitude from the resistivity of human tissue.