Regensburg 2019 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 13: Membranes and Vesicles II (joint session BP/CPP)

CPP 13.4: Vortrag

Montag, 1. April 2019, 15:45–16:00, H10

On the propagation of acoustic waves along the membrane based on the thermodynamic state of the interface — •Kevin Kang and Matthias Schneider — Technische Universität Dortmund

Biological membranes form hydrated, quasi-2D elastic interfaces, and it has been proposed that acoustic waves propagating along the membrane play a fundamental role in biological communication. Here we investigate whether thermodynamic principles can be applied on interfaces to study mechanical signaling along membranes. Using fluorescent probes embedded on an lipid monolayer assembled at the air-water interface, we excite the monolayer and measure the acoustic waves propagating along the membrane using FRET. We find that stimulation near the phase transition region of the state diagram (liquid-expanded/liquid condensed) can generate all-or-none type pulse, and the threshold behavior and the pulse shape show similarity with the nervous impulse. Altering the environment (pH, Ca2+, temperature, etc.) changes the material properties of the membrane (e.g. lateral compressibility), and the observed pulse characteristics (velocity, amplitude, period, etc.) generally agree with those expected from the compressibility profile. Furthermore, these characteristics also appear consistent with pulses seen in various excitable systems (squid axons, algae, etc.) under varying environmental conditions (e.g. increase in conduction velocity with increase in temperature). These results altogether show that the signaling properties along the interface can be derived from its state diagram and the thermodynamic properties, and they support a physical basis of communication in living systems.