Hydrodynamics of Diffusion in Lipid Membrane Simulations

TL;DR

This paper demonstrates that hydrodynamic theory accurately explains finite-size effects in lipid membrane simulations, enabling the extraction of true diffusion coefficients and membrane viscosities from large-scale molecular dynamics data.

Contribution

It introduces a hydrodynamic correction method for membrane diffusion simulations, applicable to complex and asymmetric membranes, improving the accuracy of diffusion measurements.

Findings

Hydrodynamic theory explains finite-size effects in membrane diffusion.

Oseen correction enables extraction of infinite-system diffusion coefficients.

Method applies to complex, asymmetric, and protein-embedded membranes.

Abstract

By performing molecular dynamics simulations with up to 132 million coarse-grained particles in half-micron sized boxes, we show that hydrodynamics quantitatively explains the finite-size effects on diffusion of lipids, proteins, and carbon nanotubes in membranes. The resulting Oseen correction allows us to extract infinite-system diffusion coefficients and membrane surface viscosities from membrane simulations despite the logarithmic divergence of apparent diffusivities with increasing box width. The hydrodynamic theory of diffusion applies also to membranes with asymmetric leaflets and embedded proteins, and to a complex plasma-membrane mimetic.