Characterization via atomic force microscopy of discrete plasticity in collagen fibrils from mechanically overloaded tendons: Nano-scale structural changes mimic rope failure

Samuel J. Baldwin, Laurent Kreplak, J. Michael Lee

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35 Citas (Scopus)

Resumen

Tendons exposed to tensile overload show a structural alteration at the fibril scale termed discrete plasticity. Serial kinks appear along individual collagen fibrils that are susceptible to enzymatic digestion and are thermally unstable. Using atomic force microscopy we mapped the topography and mechanical properties in dehydrated and hydrated states of 25 control fibrils and 25 fibrils displaying periodic kinks, extracted from overloaded bovine tail tendons. Using the measured modulus of the hydrated fibrils as a probe of molecular density, we observed a non-linear negative correlation between molecular density and kink density of individual fibrils. This is accompanied by an increase in water uptake with kink density and a doubling of the coefficient of variation of the modulus between kinked, and control fibrils. The mechanical property maps of kinked collagen fibrils show radial heterogeneity that can be modeled as a high-density core surrounded by a low-density shell. The core of the fibril contains the kink structures characteristic of discrete plasticity; separated by inter-kink regions, which often retain the D-banding structure. We propose that the shell and kink structures mimic characteristic damage motifs observed in laid rope strands.

Idioma originalEnglish
Páginas (desde-hasta)356-366
Número de páginas11
PublicaciónJournal of the Mechanical Behavior of Biomedical Materials
Volumen60
DOI
EstadoPublished - jul. 1 2016

Nota bibliográfica

Funding Information:
This work was supported by grants to LK and JML from the National Sciences and Engineering Research Council of Canada ( NSERC ) (Grant #: RGPIN 355291-2013). SJB received salary support from the ASPIRE CREATE program of NSERC . The authors would like to express their thanks to Jasmin Astle for valuable assistance with tissue decellularization and to Dr. Sam Veres for assistance with the mechanical overload protocol. Gratitude is also expressed to Oulton׳s Meats, Windsor, Nova Scotia for assistance in harvesting tendon samples.

Publisher Copyright:
© 2016 Elsevier Ltd.

ASJC Scopus Subject Areas

  • Biomaterials
  • Biomedical Engineering
  • Mechanics of Materials

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