Title: Biological signaling by interfacial sound pulses. A physics
approach.
Abstract: Biological signaling is usually thought of as a
combination of activation and transport. The former is triggered by local
molecular interactions and the latter is the result of molecular
diffusion. However, other fundamental physical principles of communication
have yet to be addressed.
Here, we demonstrate that lipid interfaces allow for the excitation and
propagation of sound pulses [1]. Pulses are evoked by local acidification
and propagate at velocities controlled by the interface's compressibility.
Local pH changes of up to ∆pH = 0.6 induced by the pulse are
directly observed at the interface [2]. Furthermore, simultaneously
propagating mechanical and electrical changes in the lipid interface are
detected, exposing the thermodynamic nature of these pulses.
Even more exciting, these reversible pulse like perturbations are shown to
also control the activity of membrane embedded enzymes without the need of
molecular transport (e.g. second messengers) [3]. They therefore allow for
the rapid communication between distant biological entities (e.g. receptor
and enzyme) at the speed of sound, which in within the membrane is of
order 1 m/s. The mechanism reported provides a new physical framework for
thinking and discussions about biological signaling.
[1] Griesbauer, J., Bössinger, S., Wixforth, A. & Schneider, M. F.
Propagation of 2D Pressure Pulses in Lipid Monolayers and Its Possible
Implications for Biology. Phys. Rev. Lett. 108, 198103 (2012).
[2] Fichtl, B., Shrivastava, S., Schneider, M. F. Protons at the speed of
sound: Predicting Specific biological signaling from physics. Sci. Rep. 6,
22874 (2016).
[3] Fichtl, B., Schneider, M. F., Biological Signaling by Sound. In
Preparation.