The Interplay of Electric Potential and Morphology of Biomembranes

An electric potential difference across the plasma membrane is common to all living cells and is crucial for the generation of action potentials for cell-to-cell communication. Beyond excitable nerve and muscle, bioelectric signals conjugated with the transmembrane potential control many cell behaviors such as migration, orientation, and proliferation, which play crucial role in embryogenesis, would healing, and cancer progression. The mechanisms of cellular responses to electric stimuli are virtually unknown. An electricity-centered view, epitomized by the Hodgkin-Huxley model, focuses on the voltage-dependent ion channels. However, in recent years membrane mechanics is emerging as a potentially important player: membrane deformations are detected to co-propagate with action potentials, several ion channels have been found to be both voltage-gated and mechanosensitive, and lipid rafts have been implicated as electrosensors. Assessment of the relevance of these membrane-related effects in bioelectric phenomena requires fundamental understanding of the coupling between membrane morphology, stresses, and voltage, which is limited. To fill this void, we propose a combined theoretical and experimental study of biomimetic membranes with transmembrane potential induced by an externally applied electric fields. Specifically, the proposed research seeks to determine how membrane electric potential elicits membrane responses such as stretching or compression, curvature, and phase transitions, and vice versa, how changes in the membrane morphology modulate the transmembrane potential.