Zipping mechanism for force-generation by growing filament bundles

TL;DR

This paper explores how polymerizing filament bundles generate force through a zipping mechanism, which is unaffected by buckling and depends on adhesive energy, with implications for force-induced unbinding.

Contribution

It introduces a zipping mechanism for force generation in filament bundles, highlighting its independence from buckling and its dependence on adhesive energy.

Findings

Bundles can generate force via zipping, unaffected by buckling.

Critical zipping force equals the adhesive energy gained.

Force-induced unbinding occurs when opposing force exceeds critical force.

Abstract

We investigate the force generation by polymerizing bundles of filaments, which form because of short-range attractive filament interactions. We show that bundles can generate forces by a zipping mechanism, which is not limited by buckling and operates in the fully buckled state. The critical zipping force, i.e. the maximal force that a bundle can generate, is given by the adhesive energy gained during bundle formation. For opposing forces larger than the critical zipping force, bundles undergo a force-induced unbinding transition. For larger bundles, the critical zipping force depends on the initial configuration of the bundles. Our results are corroborated by Monte Carlo simulations.