title: Packing defects and the width of biopolymer bundles.
abstract: The formation of bundles composed of actin filaments and cross-linking proteins is an essential process in the maintenance of the cells' cytoskeleton. It has also been recreated by in-vitro experiments, where actin networks are routinely produced to mimic and study the cellular structures. It has been observed that these bundles seem to have a well-defined width distribution, which has not been adequately described theoretically. We propose here that packing defects of the filaments, quenched and random, contribute an effective repulsion that counters the cross-linking adhesion energy and leads to a well-defined bundle width. This is a two-dimensional strain-field version of the classic Rayleigh instability of charged droplets.
authors.affiliation: Department of Chemical Physics, The Weizmann Institute of Science, POB 26, Rehovot, Israel.
authors.forename: Nir S
authors.initials: NS
authors.lastname: Gov