Orientationally ordered aggregates of stiff polyelectrolytes in the presence of multivalent salt

TL;DR

This study uses molecular dynamics simulations to explore how multivalent salt influences the aggregation and orientation of stiff polyelectrolytes, revealing formation of metastable structures and ordered bundles.

Contribution

It provides new insights into the role of multivalent salt in inducing orientational order and aggregation in stiff polyelectrolytes, supported by detailed simulation analysis.

Findings

Formation of long-lived metastable structures similar to actin filaments

Finite-sized bundles of parallel polyelectrolytes form at equilibrium

Preferred angles and interaction types depend on salt concentration

Abstract

Aggregation of stiff polyelectrolytes in solution and angle- and distance-dependent potential of mean force between two like-charged rods are studied in the presence of 3-valent salt using molecular dynamics simulations. In the bulk solution, formation of long-lived metastable structures with similarities to the raft-like structures of actin filaments is observed within a range of salt concentration. The system finally goes to a state with lower free energy in which finite-sized bundles of parallel polyelectrolytes form. Preferred angle and interaction type between two like-charged rods at different separations and salt concentrations are also studied, which shed some light on the formation of orientationally ordered structures.