Shearing in a biomimetic apatite-protein composite: molecular dynamics of slip zone formation, plastic flow and backcreep mechanisms

PLoS One. 2014 Apr 1;9(4):e93309. doi: 10.1371/journal.pone.0093309. eCollection 2014.

Abstract

We report molecular dynamics simulations of shear in a biomimetic hydroxyapatite-collagen composite. Our model exhibits elastic properties fully dominated by the inorganic component. However, beyond the elastic regime the biomolecules along with the hierarchical nature of the composite account for the formation of structure-inherent slip zones. These accommodate shear without compromising the overall structure and lead to the sliding of intrinsically defined rods at roughly constant restoring force. Upon releasing load, rod displacement is reversible and backcreep is observed as gradual ionic rearrangement in the slip zone, subjected to an activation barrier.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apatites / chemistry*
  • Biomimetic Materials / chemistry
  • Biomimetics*
  • Collagen / chemistry
  • Durapatite / chemistry
  • Molecular Dynamics Simulation
  • Proteins / chemistry*
  • Shear Strength*

Substances

  • Apatites
  • Proteins
  • Collagen
  • Durapatite

Grants and funding

The authors gratefully acknowledge DFG grant ZA 420-7, and the cluster of excellence ‘engineering of advanced materials’ EXC 315. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.