MC simulations of water meniscus in nanocontainers: explaining the collapse of viral particles due to capillary forces

Abstract

By using a lattice‐gas model, we report numerical simulation for the action of capillary forces of water confined at the nanoscale during desiccation of viruses. Results are compared with structural effects of desiccation measured by Atomic Force Microscopy on individual viruses of the bacteriophage ϕ 29 and the minute virus of mice (MVM). Structural integrity is found for theMVM, but not for the ϕ 29. Numerical simulations show that in the desiccation process, the meniscus shape formed inside the capsids strongly depends on the virus symmetry. This suggests that capillary forces could play a key role on the explanation of the different measured collapse processes (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Exploring the role of genome and structural ions in preventing viral capsid collapse during dehydration

“…2 nm) and narrow (about 0.3 nm) means of traversing a protein body [45,49,50]. Since virus wall is the border of the virion with the external environment, its structure and porosity determine the release of water during desiccation [35]. In this respect, the hydrophobic character of the 12 transversal channels at the pentons of TrV capsid seems to influence the structure of virus particles after desiccation.…”

“…Specifically, freeze drying of virus structures avoid menisci formation and reduce virus collapse during dehydration process [30]. These forces strongly depend on the existence of nanometric channels and pores at the virus shell that regulate the way that the water escapes from the virus [35].…”

Identification of water content in nanocavities

“…The conditions considered correspond to equilibrium bulk evaporation. The concrete expression of the Hamiltonian we have considered is reported in [5] and includes water-water, water-tip, and water-substrate terms. For a given set of geometrical parameters and physical conditions (temperature and humidity), an approximate shape of the water meniscus is obtained from an averaging procedure involving hundreds of different configurations.…”

“…The meniscus formation along with the geometry of the nanocavity allows capillary force to modify the mechanical stability towards collapse [5]. An important issue that arises from these AFM studies on biological samples is whether the condensation of water in these viral nanocavities may be detected by a direct measurement.…”