ELECTROSTATICALLY INDUCED BUNDLE FORMATION OF RODLIKE POLYELECTROLYTES COMPARISON OF PREDICTIONS FROM MONTE CARLO SIMULATIONS WITH EXPERIMENTS ON FD AND M13 VIRUS PARTICLES

摘要

This work compares the electrostatic bundling of two Inovirus particles: fd and M13, that are structurally identical except that the effective axial charge density of M13 is approximately 30% lower than that of fd. The electrostatic force (or osmotic pressure) between these ordered biopolyelectrolytes, as a function of inter-rod separation, has been calculated with Monte Carlo simulations. Comparison is made with experiments on the bundling of fd and M13 caused by divalent ions, as detected by light scattering. In the theoretical calculations, the bundling results from electrostatic attraction between the neighbouring polyelectrolytes, caused by the correlated interactions between the ion clouds. The importance of this effect (i. e. capacity to induce bundling) is governed by surface charge density of the polyelectrolyte, amount of multivalent ion present, charge and size of the hydrated multivalent ion. These predictions are in very good agreement with the presented experimental results on bundling of fd and M13 caused by Ca~(2+) and Mg~(2+).