Controlling Anomalous Diffusion in Lipid Membranes

H. L. E. Coker; M. R. Cheetham; D. R. Kattnig; Y. J. Wang; S. Garcia-Manyes; M. I. Wallace

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arXiv · 1709.04698

Controlling Anomalous Diffusion in Lipid Membranes

H. L. E. Coker·M. R. Cheetham·D. R. Kattnig·Y. J. Wang·S. Garcia-Manyes·M. I. Wallace

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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.

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H. L. E. Coker, M. R. Cheetham, D. R. Kattnig, Y. J. Wang, S. Garcia-Manyes, M. I. Wallace. 2017-09-14. Controlling Anomalous Diffusion in Lipid Membranes. https://arxiv.org/abs/1709.04698

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