Controlling Anomalous Diffusion in Lipid Membranes
Abstract
Diffusion in cell membranes is not just simple two-dimensional Brownian motion, but typically depends on the timescale of the observation. The physical origins of this anomalous sub-diffusion are unresolved, and model systems capable of quantitative and reproducible control of membrane diffusion have been recognised as a key experimental bottleneck. Here we control anomalous dif- fusion using supported lipids bilayers containing lipids derivatized with polyethylene glycol (PEG) headgroups. Bilayers with specific excluded area fractions are formed by control of PEG-lipid mole fraction. These bilayers exhibit a switch in diffusive behaviour, becoming anomalous as bilayer continuity is disrupted. Diffusion in these bilayers is well-described by a power-law dependence of the mean-square displacement with observation time. The parameters describing this diffusion can be tailored by simply controlling the mole fraction of PEG-lipid, producing bilayers that exhibit diffusive behaviour with similar characteristics to those observed in biological membranes.
Cite
@article{arxiv.1709.04698,
title = {Controlling Anomalous Diffusion in Lipid Membranes},
author = {H. L. E. Coker and M. R. Cheetham and D. R. Kattnig and Y. J. Wang and S. Garcia-Manyes and M. I. Wallace},
journal= {arXiv preprint arXiv:1709.04698},
year = {2017}
}