Mechanical Properties of Viral Capsids

TL;DR

This paper investigates the mechanical properties and stress distribution of viral capsids, comparing discrete polyhedral models with continuum elasticity theory, and explores mechanisms of shell failure and biological implications.

Contribution

It introduces a detailed analysis of stress distribution in viral capsids considering their discrete polyhedral structure, advancing understanding beyond classical elasticity models.

Findings

Stress distribution varies with capsid geometry and internal pressure

Discrepancies between discrete models and continuum elasticity are identified

Insights into failure mechanisms like cracking and bursting are provided

Abstract

Viruses are known to tolerate wide ranges of pH and salt conditions and to withstand internal pressures as high as 100 atmospheres. In this paper we investigate the mechanical properties of viral capsids, calling explicit attention to the inhomogeneity of the shells that is inherent to their discrete and polyhedral nature. We calculate the distribution of stress in these capsids and analyze their response to isotropic internal pressure (arising, for instance, from genome confinement and/or osmotic activity). We compare our results with appropriate generalizations of classical (i.e., continuum) elasticity theory. We also examine competing mechanisms for viral shell failure, e.g., in-plane crack formation versus radial bursting. The biological consequences of the special stabilities and stress distributions of viral capsids are also discussed.