Red Blood Cell Thermal Fluctuations: Comparison Between Experiment and Molecular Dynamics Simulations

We outline a new method of analysis of thermal shape fluctuations of red blood cells, based on comparison between experiments and coarse-grained molecular dynamics simulations. The fluctuations of 2D equatorial contours of red blood cells are recorded experimentally using fast phase-contrast video microscopy, from which the fluctuation spectrum is calculated. The spectrum is compared to the corresponding contour fluctuation spectrum obtained from a finite-temperature particle-dynamics simulation, modelling a cell with bending and shear elasticity and conserved volume and surface area. We demonstrate that the simulation correctly describes the mean cell shape as well as the membrane thermal fluctuations, returning physically sound values for the relevant membrane elastic moduli.