  The mechanical properties of biopolymer networks depend on their mean
coordination number and stress state. Models based on spring networks have been
shown to capture some properties of materials such as the actin cortex, but the
effect of prestress combined with filament pruning, known to exist in the
cortex, has not been studied. We show that in central-force spring networks
below isostatic coordination that are rigidified by prestress, details of the
pruning method significantly affect mechanical properties: networks pruned by a
tension-inhibited method not only have a larger shear modulus than
randomly-pruned networks, but require far smaller initial prestrains in order
to remain rigid at biologically-relevant coordinations. These findings suggest
a possible reason for the common motif of tension-inhibited filament-cleaving
proteins in biopolymer networks.
