Elasticity of Semiflexible Biopolymer Networks

We develop a model for cross-linked gels and sterically entangled solutions of semiflexible biopolymers such as F-actin. Such networks play a crucial structural role in the cytoskeleton of cells. We show that the rheologic properties of these networks can result from nonclassical rubber elasticity. This model can explain a number of elastic properties of such networks in vitro, including the concentration dependence of the storage modulus and yield strain.