Planar biaxial mechanical behavior of bioartificial tissues possessing prescribed fiber alignment

Choon Sik Jhun, Michael C. Evans, Victor H Barocas, Robert T Tranquillo

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

Though it is widely accepted that fiber alignment has a great influence on the mechanical anisotropy of tissues, a systematic study of the influence of fiber alignment on the macroscopic mechanical behavior by native tissues is precluded due to their predefined microstructure and heterogeneity. Such a study is possible using collagen-based bioartificial tissues that allow for alignment to be prescribed during their fabrication. To generate a systemic variation of strength of fiber alignment, we made cruciform tissue constructs in Teflon molds that had arms of different aspect ratios. We implemented our anisotropic biphasic theory of tissue-equivalent mechanics to simulate the compaction by finite element analysis. Prior to tensile testing, the construct geometry was standardized by cutting test samples with a 1:1 cruciform punch after releasing constructs from the molds. Planar biaxial testing was performed on these samples, after stretching them to their in-mold dimensions to recover in-mold alignment, to observe the macroscopic mechanical response with simultaneous fiber alignment imaging using a polarimetry system. We found that the strength of fiber alignment of the samples prior to release from the molds linearly increased with anisotropy of the mold. In testing after release, modulus ratio (modulus in fiber direction/modulus in normal direction) was greater as the initial strength of fiber alignment increased, that is, as the aspect ratio increased. We also found that the fiber alignment strength and modulus ratio increased in a hyperbolic fashion with stretching for a sample of given aspect ratio.

Original languageEnglish (US)
Article number81006-1
JournalJournal of Biomechanical Engineering
Volume131
Issue number8
DOIs
StatePublished - Aug 1 2009

Fingerprint

Fungi
Tissue
Fibers
Anisotropy
Molds
Aspect ratio
Finite Element Analysis
Stretching
Polytetrafluoroethylene
Mechanics
Polarimeters
Collagen
Tensile testing
Testing
Polytetrafluoroethylenes
Compaction
Imaging techniques
Finite element method
Fabrication
Microstructure

Keywords

  • Bioartificial tissue
  • Collagen fiber alignment
  • Planar biaxial testing
  • Polarimetry
  • Tissue mechanical anisotropy
  • Tissue modulus
  • Tissue tensile mechanical properties

Cite this

Planar biaxial mechanical behavior of bioartificial tissues possessing prescribed fiber alignment. / Jhun, Choon Sik; Evans, Michael C.; Barocas, Victor H; Tranquillo, Robert T.

In: Journal of Biomechanical Engineering, Vol. 131, No. 8, 81006-1, 01.08.2009.

Research output: Contribution to journalArticle

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