Unlike polyacrylamide (black), natural networks become more difficult to deform with greater strain.
JANMEY/MACMILLAN
Natural networks, such as collagen gels or cytoskeletal webs, have the ability to increase their stiffness with increasing strain. This unique feature is an advantage over most synthetic fibers. If blood vessels were made of rubber tubing, for example, the pressure from a heart beat would vastly increase vessel diameter. But collagen's nonlinear elasticity prevents such a drastic endothelial deformation.
This ability is usually explained by the heterogeneous nature of biological gels—perhaps tauter filaments take over at increasing strains. But in vitro measurements by Storm et al. now show that uniform biopolymer gels also exhibit nonlinear elasticity. The authors then produced a...
