Hot from the Mussel Lab: Biophysics of Sound Pulses in Lipid Membranes

In this work we highlight recent experimental and theoretical investigations of sound in lipid membranes and their potential function in biology. Compression waves within lipid membranes propagate electrical, chemical, and thermal variations in addition to the mechanical changes in lateral pressure and lipid density, and can interact with nearby ions, polymers, and water.  In particular, waves that reversibly traverse the melting transition of the lipid system display unusual nonlinear properties, including a sigmoidal response to excitation amplitude and annihilation upon collision. We describe many striking similarities between nonlinear sound waves and action potentials that propagate along the lipid membrane of excitable cells, and are principally associated with behavioral activities of many organisms. Clearly the cellular system is more complex than a synthetic, flat, homogeneous lipid layer. Nevertheless, the main properties of these two types of pulses may be governed by the same fundamental principles. More information may be found here.