Failure of mineralized collagen fibrils: Modeling the role of collagen cross-linking

Thomas Siegmund, Matthew R. Allen, David B. Burr

Research output: Contribution to journalArticle

79 Scopus citations

Abstract

Experimental evidence demonstrates that collagen cross-linking in bone tissue significantly influences its deformation and failure behavior yet difficulties exist in determining the independent biomechanical effects of collagen cross-linking using in vitro and in vivo experiments. The aim of this study is to use a nano-scale composite material model of mineral and collagen to determine the independent roles of enzymatic and non-enzymatic cross-linking on the mechanical behavior of a mineralized collagen fibril. Stress-strain curves were obtained under tensile loading conditions without any collagen cross-links, with only enzymatic cross-links (modeled by cross-linking the end terminal position of each collagen domain), or with only non-enzymatic cross-links (modeled by random placement of cross-links within the collagen-collagen interfaces). Our results show enzymatic collagen cross-links have minimal effect on the predicted stress-strain curve and produce a ductile material that fails through debonding of the mineral-collagen interface. Conversely, non-enzymatic cross-links significantly alter the predicted stress-strain response by inhibiting collagen sliding. This inhibition leads to greater load transfer to the mineral, which minimally affects the predicted stress, increases modulus and decreases post-yield strain and toughness. As a consequence the toughness of bone that has more non-enzymatically mediated collagen cross-links will be drastically reduced.

Original languageEnglish (US)
Pages (from-to)1427-1435
Number of pages9
JournalJournal of Biomechanics
Volume41
Issue number7
DOIs
StatePublished - 2008

Keywords

  • Bone
  • Collagen
  • Computational mechanics
  • Cross-linking
  • Fibril

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine

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