Sound pulses in lipid membranes and their potential function in biology

Experimental observations in lipid monolayers at the air-water interface have demonstrated that solitary sound pulses can be excited. These pulses 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 addition, it was demonstrated that sound pulses that reversibly traverse the melting transition between the so-called liquid-expanded and liquid-condensed phases display unusual nonlinear properties that are strikingly similar to those of action potentials in living cells. This review describes recent experimental and theoretical investigations of sound in lipid membranes and their potential function in biology.