A design framework for actively crosslinked filament networks

TL;DR

This paper develops a theoretical framework to understand how microscopic forces from crosslinking molecules influence the macroscopic mechanical properties of highly crosslinked filament networks, such as those in the cytoskeleton.

Contribution

It introduces a phenomenological force model and derives a predictive theory linking crosslink properties to network mechanics, advancing understanding of cytoskeletal behavior.

Findings

Force exertion by crosslinks determines network stiffness

Material properties depend on crosslink density and force characteristics

Framework enables design of networks with tailored properties

Abstract

Living matter moves, deforms, and organizes itself. In cells this is made possible by networks of polymer filaments and crosslinking molecules that connect filaments to each other and that act as motors to do mechanical work on the network. For the case of highly cross-linked filament networks, we discuss how the material properties of assemblies emerge from the forces exerted by microscopic agents. First, we introduce a phenomenological model that characterizes the forces that crosslink populations exert between filaments. Second, we derive a theory that predicts the material properties of highly crosslinked filament networks, given the crosslinks present. Third, we discuss which properties of crosslinks set the material properties and behavior of highly crosslinked cytoskeletal networks. The work presented here, will enable the better understanding of cytoskeletal mechanics and its molecular underpinnings. This theory is also a first step towards a theory of how molecular perturbations impact cytoskeletal organization, and provides a framework for designing cytoskeletal networks with desirable properties in the lab.