Details

Autor(en) / Beteiligte

• Maciel, Dylan
• Veres, Samuel P.
• Kreuzer, Hans Juergen
• Kreplak, Laurent

Titel

Quantitative phase measurements of tendon collagen fibres

Ist Teil von

• Journal of biophotonics, 2017-01, Vol.10 (1), p.111-117

Ort / Verlag

Weinheim: WILEY‐VCH Verlag

Erscheinungsjahr

2017

Quelle

Wiley Online Library All Journals

Beschreibungen/Notizen

• Collagen is the main component of structural mammalian tissues. In tendons, collagen is arranged into fibrils with diameters ranging from 30 nm to 500 nm. These fibrils are further assembled into fibres several micrometers in diameter. Upon excessive thermal or mechanical stress, damage may occur in tendons at all levels of the structural hierarchy. At the fibril level, reported damage includes swelling and the appearance of discrete sites of plastic deformation that are best observed at the nanometer‐scale using, for example, scanning electron microscopy. In this paper, digital in‐line holographic microscopy is used for quantitative phase imaging to measure both the refractive index and diameter of collagen fibres in a water suspension in the native state, after thermal treatments, and after mechanical overload. Fibres extracted from tendons and subsequently exposed to 70 °C for 5, 15, or 30 minutes show a significant decrease in refractive index and an increase in diameter. A significant increase in refractive index is also observed for fibres extracted from tendons that were subjected to five tensile overload cycles. Quantitative phase imaging using digital inline holography (DIHM) allows the direct determination of the optical index of micron scale objects. Using this technique we measure the optical index of collagen fibres extracted from tendons in water. Heat exposure and tensile overload, both decrease the optical index of the fibres by 0.008 or less, demonstrating that DIHM can be used to quantify changes in collagen fibres a few microns in diameter.