Controlling Anomalous Diffusion in Lipid Membranes

TY - JOUR

T1 - Controlling Anomalous Diffusion in Lipid Membranes

AU - Coker, H. L. E.

AU - Cheetham, M. R.

AU - Kattnig, D. R.

AU - Wang, Y. J.

AU - Garcia-Manyes, S.

AU - Wallace, M. I.

PY - 2018/12/14

Y1 - 2018/12/14

N2 - 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.

AB - 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.

KW - physics.bio-ph

U2 - 10.1016/j.bpj.2018.12.024

DO - 10.1016/j.bpj.2018.12.024

M3 - Article

SN - 0006-3495

JO - Biophysical Journal

JF - Biophysical Journal

ER -