Samuel Veres Lab published new work using CHP technology to evaluate the molecular damage caused to tendons that serve a positional function and tendons with energy-storing functions. Together with SHG and AFM they were able to rupture these tendons and saw that there is a difference in the molecular damage caused to the collagen triple helix depending on the type of tendon. This image shows a positional tendon that has been ruptured and shows short "nodes" of intact collagen while the rest of the ruptured segment showing kinking and periphery delamination in AFM stains positively for the presence of denatured collagen.
Abstract: The collagen-based tissues of animals are hierarchical structures: even tendon, the simplest collagenous tissue, has seven to eight levels of hierarchy. Tailoring tissue structure to match physiological function can occur at many different levels. We wanted to know if the control of tissue architecture to achieve function extends down to the nanoscale level of the individual, cable-like collagen fibrils. Using tendons from young adult bovine forelimbs, we performed stress-strain experiments on single collagen fibrils extracted from tendons with positional function, and tendons with energy storing function. Collagen fibrils from the two tendon types, which have known differences in intermolecular crosslinking, showed numerous differences in their responses to elongation. Unlike those from positional tendons, fibrils from energy storing tendons showed high strain stiffening and resistance to disruption in both molecular packing and conformation, helping to explain how these high stress tissues withstand millions of loading cycles with little reparative remodeling. Functional differences in load-bearing tissues are accompanied by important differences in nanoscale collagen fibril structure.
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