Mechanical properties and microdomain separation of fluid membranes with anchored polymers

The entropic effects of anchored polymers on biomembranes are studied using simulations
of a meshless membrane model combined with anchored linear polymer chains. The
bending rigidity and spontaneous curvature are investigated for anchored ideal and
excluded-volume polymer chains. Our results are in good agreement with the previous
theoretical predictions. It is found that the polymer reduces the line tension of membrane
edges, as well as the interfacial line tension between membrane domains, leading to
microdomain formation. Instead of the mixing of two phases as observed in typical binary
fluids, densely anchored polymers stabilize small domains. A mean field theory is proposed
for the edge line tension reduced by anchored ideal chains, which reproduces our
simulation results well.