Soft Matter Seminar: Electrical, chemical and mechanical aspects of acoustic pulses in membranes
Matan Mussel, NICHD, National Institutes of Health
Abstract: Action potentials (these electrical pulses we have in our brain) show remarkable similarities to acoustic pulses that propagate along lipid monolayers, while causing a local reversible phase transition. Despite the striking experimental similarities, a comprehensive theoretical study of acoustic pulses in lipid membranes is still lacking. In addition, acoustics remains a non-intuitive mechanism for action potentials because it is typically associated with mechanical changes while action potentials are most commonly measured electrically. In this work, we demonstrate that an idealized description of an interface near phase transition captures many properties of acoustic pulses in lipid membranes, as well as action potentials in living cells. Furthermore, we show that the discrepancy is lifted upon considering the electrical and chemical aspects of the interface, in addition to its mechanical properties. Our theory is based on classical physical principles that must exist in the soft material and contains no fit parameters. The pulses that emerge are semi-quantitatively similar in shape and scales (time, velocity and voltage) to action potentials, demonstrate a sigmoidal response to stimulation amplitude (an ‘all-or-none’ behavior), and annihilate upon collision.
Friday, May 31 at 11:00am
Regents Hall, 351
3700 O St. NW