Urea-Mediated Anomalous Diffusion in Supported Lipid Bilayers

Abstract: Diffusion in biological membranes is seldom simply Brownian motion; instead, the rate of diffusion is dependent on the timescale of observation and so is often described as anomalous. In order to help better understand this phenomenon, model systems are needed where the anomalous subdiffusion of the lipid bilayer can be tuned and quantified. We recently demonstrated one such model by controlling the excluded area fraction in supported lipid bilayers (SLBs) through the incorporation of lipids derivatised with polyethylene glycol. Here we extend this work, using urea to induce anomalous subdiffusion in SLBs. By tuning incubation time and urea concentration, we produce DCPC bilayers that exhibit anomalous behaviour on the same scale observed in biological membranes.