Dynamics of Flexible Viruses in Polymer Solutions

Abstract

We examine the coupling of the dynamics of flexible viral nanoparticles to the dynamics of comparably sized polymer chains. Using fluorescence microscopy, we quantify the dynamics of three filamentous viruses, potato virus M (PVM), M13, and pf1, that are suspended in semidilute solutions of partially hydrolyzed polyacrylamide. The dynamics of the viral nanoparticles are approximately diffusive on accessible time and length scales, but the distributions of displacements are non-Gaussian and exhibit increasingly extended tails as the aspect ratio of the viruses or the polymer concentration is increased. The long-time diffusion coefficients do not collapse onto a universal curve based on existing models for rodlike or spherical nanoparticles that are comparably sized to the polymer chains. Instead, the diffusivities appear to collapse as a function of the ratio of the polymer correlation length and a length scale intermediate between the virus radius and length, indicating that the hydrodynamic coupling to the polymer dynamics is affected by the virus anisotropy and flexibility.