Quantification of Interfibrillar Shear Stress in Aligned Soft Collagenous Tissues via Notch Tension Testing
Date
2015-10-15
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Journal ISSN
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Publisher
Nature Publishing Group
Abstract
The mechanical function of soft collagenous tissues is largely determined by their hierarchical
organization of collagen molecules. While collagen fibrils are believed to be discontinuous and
transfer load through shearing of the interfibrillar matrix, interfibrillar shear stresses have never been
quantified. Scaling traditional shear testing procedures down to the fibrillar length scale is impractical
and would introduce substantial artifacts. Here, through the use of a novel microscopic variation of
notch tension testing, we explicitly demonstrate the existence of interfibrillar shear stresses within
tendon fascicles and provide the first measurement of their magnitude. Axial stress gradients along
the sample length generated by notch tension testing were measured and used to calculate a value
of 32 kPa for the interfibrillar shear stress. This estimate is comparable to the interfibrillar shear stress
predicted by previous multiscale modeling of tendon fascicles, which supports the hypothesis that
fibrils are discontinuous and transmit load through interfibrillar shear. This information regarding the
structure-function relationships of tendon and other soft collagenous tissues is necessary to identify
potential causes for tissue impairment with degeneration and provide the foundation for developing
regenerative repair strategies or engineering biomaterials for tissue replacement.
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Citation
Szczesny, S. E. et al. Quantification of Interfibrillar Shear Stress in Aligned Soft Collagenous Tissues via Notch Tension Testing. Sci. Rep. 5, 14649; doi: 10.1038/srep14649 (2015).