Fibrillar Structure and Mechanical Properties of Collagen

Fratzl, Peter; Misof, K.; Zizak, Ivo; Rapp, Gert; Amenitsch, Heinz; Bernstorff, Sigrid

doi:10.1006/jsbi.1998.3966

Cited by 589 publications

(502 citation statements)

References 15 publications

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“…The collagen fibrils in leather are less aligned than in pericardium, allowing more possibility for realignment. For rat tail tendon, this ratio is 40% for the second (linear) region of the strain curve, 29 perhaps reflecting the high alignment of collagen in tendon.…”

Section: Resultsmentioning

confidence: 96%

Poisson's ratio of collagen fibrils measured by small angle X-ray scattering of strained bovine pericardium

Wells

Sizeland

Kayed

et al. 2015

Journal of Applied Physics

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Type I collagen is the main structural component of skin, tendons, and skin products, such as leather. Understanding the mechanical performance of collagen fibrils is important for understanding the mechanical performance of the tissues that they make up, while the mechanical properties of bulk tissue are well characterized, less is known about the mechanical behavior of individual collagen fibrils. In this study, bovine pericardium is subjected to strain while small angle X-ray scattering (SAXS) patterns are recorded using synchrotron radiation. The change in d-spacing, which is a measure of fibril extension, and the change in fibril diameter are determined from SAXS. The tissue is strained 0.25 (25%) with a corresponding strain in the collagen fibrils of 0.045 observed. The ratio of collagen fibril width contraction to length extension, or the Poisson's ratio, is 2.1 ± 0.7 for a tissue strain from 0 to 0.25. This Poisson's ratio indicates that the volume of individual collagen fibrils decreases with increasing strain, which is quite unlike most engineering materials. This high Poisson's ratio of individual fibrils may contribute to high Poisson's ratio observed for tissues, contributing to some of the remarkable properties of collagen-based materials.

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Section: Resultsmentioning

confidence: 96%

Poisson's ratio of collagen fibrils measured by small angle X-ray scattering of strained bovine pericardium

Wells

Sizeland

Kayed

et al. 2015

Journal of Applied Physics

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“…During loading of collagen molecules, fibrils, and fibril bundles deform and finally fail by a process termed defibrillation. Up to a strain of 2% (toe region), stretching of the triple helix is the predominant mechanism of deformation [268][269][270][271] and corresponds to the gradual removal of a macroscopic crimp in the collagen fibrils [272][273][274][275][276][277][278][279][280][281]. This macroscopic crimp has been characterised as the shock absorber of tendons that permits non-damaging longitudinal elongation of fibrils within the tissue [261,282].…”

Section: Mechanical Properties Of Tendon Tissuementioning

confidence: 99%

The past, present and future in scaffold-based tendon treatments

Lomas

Ryan

Sorushanova

et al. 2015

Advanced Drug Delivery Reviews

183

188

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“…For reduced loads, the collagen fibres are in relaxed conditions and appear wavy and crimped (Section 4.2 includes some additional microscopic information) [5,22,24]. ii) Next, a region of linear behaviour develops from point A to point B.…”

Section: Tensile Testsmentioning

confidence: 99%

Determination of the mechanical properties of normal and calcified human mitral chordae tendineae

Casado

Diego

Ferreño

et al. 2012

Journal of the Mechanical Behavior of Biomedical Materials

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The aim of the present research is to determine the influence of the calcification of human mitral valves on the mechanical properties of their marginal chordae tendineae. The study was performed on marginal chords obtained from thirteen human mitral valves, explanted at surgery, including six non-calcified, four moderately calcified and three strongly calcified valves. The mechanical response of the chords from the non-calcified and moderately calcified valves was determined by means of quasi-static tensile tests (the poor condition of the strongly calcified valves prevented them from being mechanically characterised). The material parameters that were obtained and analysed (the Young's modulus, the secant modulus, the proportional limit stress, the ultimate strength, the strain at fracture and the density of energy stored up to maximum load) revealed noticeable differences in mechanical behaviour between the two groups of mitral chordae tendineae. Large scatter was obtained in all cases, nevertheless, considering the mean values, it was observed that the normal chords are between three and seven times stiffer or more resistant than the moderately calcified ones. On the contrary, the results obtained for the strain at fracture showed a rather different picture as, in this case, no significant differences were observed between the two families of chords. A scanning electron microscopy study was conducted in order to find out the relevant features of the calcium deposits present in the calcified chordae tendineae. In addition, the general aspects appreciated in the stress vs. strain curves were correlated with the collagen morphological evidences determined microscopically. Finally, the calcium content present in the three groups of chords was quantitatively determined through atomic absorption spectroscopy; then, the relation between the mechanical properties of normal and moderately calcified chords as a function of its calcium content was obtained. This analysis confirmed the existence of a strong correlation between calcium content and stiffness or resistance whereas the influence on the ductility seems to be negligible.

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Fibrillar Structure and Mechanical Properties of Collagen

Cited by 589 publications

References 15 publications

Poisson's ratio of collagen fibrils measured by small angle X-ray scattering of strained bovine pericardium

Poisson's ratio of collagen fibrils measured by small angle X-ray scattering of strained bovine pericardium

The past, present and future in scaffold-based tendon treatments

Determination of the mechanical properties of normal and calcified human mitral chordae tendineae

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