(527i) High Resolution Optical and Electrical Recording of Free Standing Lipid Bilayers

Cellular membranes possess a transmembrane electric potential of ∼100 mV but this fact, which is generally conserved across all cell and organelle types, is often neglected in model phospholipid bilayer studies. The cause of this potential is due to a variety of factors operating in tandem, namely the action of ion pumps to maintain an osmotic pressure difference, the presence of charged membrane proteins, membrane curvature, and asymmetry of charged lipid composition. This talk will highlight recent work evaluating the electromechanical properties of model lipid bilayers which dictate how cell membranes respond to electrical stress. Simultaneous optical and capacitive monitoring of a large-area free standing model membrane provides unique insight into the dynamic response as the bilayer compresses and stretches due to the applied field. Measurements of the thickness-voltage relationships for monocomponent bilayers and lipid mixtures containing different degrees of saturated lipids and anionic lipids will be presented to elucidate the factors that govern membrane elastic properties. These properties play an important role many biological processes, namely the function of membrane proteins, and as an outlook initial experiments incorporating model membrane proteins will be discussed.