Three-dimensional simulation of nanoindentation response of viral capsids. shape and size effects

Aylin Ahadi, Josep Colomo, Alex Evilevitch

Research output: Contribution to journalArticlepeer-review


The nanoindentation response of empty viral capsids is modeled using three-dimensional finite element analysis. Simulation with two different geometries, spherical and icosahedral, is performed using the finite element code Abaqus. The capsids are modeled as nonlinear Hookean elastic, and both small and large deformation analysis is performed. The Young's modulus is determined by calibrating the force-indentation curve to data from atomic force microscopy (AFM) experiments. Force-indentation curves for three different viral capsids are directly compared to experimental data. Predictions are made for two additional viral capsids. The results from the simulation showed a good agreement with AFM data. The paper demonstrates that over the entire range of virus sizes (or Föppl-von Karman numbers) spherical and icosahedral models yield different force responses. In particular, it is shown that capsids with dominantly spherical shape (for low Föppl-von Karman numbers) exhibit nearly linear relationship between force and indentation, which has been experimentally observed on the viral shell studies so far. However, we predict that capsids with significant faceting (for large Föppl-von Karman numbers) and thus more pronounced icosahedral shape will exhibit rather nonlinear deformation behavior.

Original languageEnglish (US)
Pages (from-to)3370-3378
Number of pages9
JournalJournal of Physical Chemistry B
Issue number11
StatePublished - Mar 19 2009
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry


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