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BP: Fachverband Biologische Physik

BP 9: Poster II

BP 9.19: Poster

Montag, 16. März 2020, 17:30–19:30, P2/2OG

Influence of viscoelastic properties on the speed of sound in lipid membranes — Matthias F. Schneider and •Gregor Haider — Med. & Biol. Physik, TU Dortmund, Dortmund, Germany

There is an ongoing controversy on the physical origin of nerve pulse propagation. Besides the standard model of Hodgkin and Huxley a physical theory based on momentum conservation and thermodynamics in which density pulses form the basis of action potentials is proposed. In order to test the latter we study the velocity variation of density pulses both in theory and experiment. Indeed the velocity variation of action potentials by at least five orders of magnitude across different species and even up to 3 orders of magnitude within the same system represents an excellent test against theories for pulse propagation in biology and can hence presumably provide new clues to the current debate on the origin of the action potentials. We here explore the predictions of a thermodynamic theory of pulses and study the role of viscoelastic properties of the membrane as well as the surrounding medium on pulse propagation. We show experimentally that an increased shear viscosity of the subphase decreases the velocity of acoustic pulses in lipid monolayers in accordance with theoretical prediction. Finally, the influence of the 2-dimensional dilational surface viscosity on pulse propagation is investigated theoretically and experimentally.