Fluctuations of red blood cell membranes: The role of cytoskeleton

TL;DR

This theoretical study models red blood cell membrane fluctuations by coupling the membrane to a sparse cytoskeleton network, revealing how coupling strength influences fluctuation spectra at different wavelengths.

Contribution

It introduces an exactly solvable model of membrane-cytoskeleton coupling, elucidating how this interaction affects membrane undulation behavior across various length scales.

Findings

Coupling modifies fluctuation spectrum at wavelengths longer than the mesh size.

Membrane behavior remains fluid-like at shorter wavelengths despite coupling.

Fluctuation spectra depend on bilayer bending energy and coupling strength.

Abstract

We theoretically investigate the membrane fluctuations of red blood cells with focus laid on the role of the cytoskeleton, viewing the system as a membrane coupled to sparse spring network. This model is exactly solvable and enables us to examine the coupling strength dependence of the membrane undulation. We find that the coupling modifies the fluctuation spectrum at wavelengths longer than the mesh size of the network, while leaving the fluid-like behavior of the membrane intact at shorter wavelengths. The fluctuation spectra can be markedly different, depending on not only the relative amplitude of the bilayer bending energy with respect to the cytoskeleton deformation energy but also the bilayer-cytoskelton coupling strength.