  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.
