Karl Franzens University Graz

Graz University of Technology 

Collagen - the glue holding our bodies together
Philipp J. Thurner
Institute of Lightweight Design and Structural Biomechanics, TU Wien
16:15 - 17:15 Tuesday 19 October 2021 TUG hybrid event: lecture hall P2 / Webex

Video: https://tugraz.webex.com/meet/p.hadley

Biological tissues with passive mechanical function in the human body are generally rich in collagen. Collagens provide both stiffness and toughness. Macroscopically, relationships between tissue-structure, composition and mechanical function have been explored, but comparatively little has been done in this context on the micro- and nanometer length scale. Yet, perhaps the most important basic structural building block of collagen-rich tissues can be found at these scales: the collagen fibril. Such fibrils are rope-like structures with diameters in the range of tens to hundreds of nanometers, having extreme aspect ratios with lengths reaching up to centimeters. These fibrils, in turn are composed of tropocollagen molecules, which have so far not been experimentally mechanically characterized in a satisfying manner.
Experiments on individual collagen fibrils show, that indeed chemical modifications in form of cross-links modify mechanics. Additionally, also hydration has effects of similar magnitude. Mutations of the collagen encoding genes can result in severe conditions, such as brittle bones (osteogenesis imperfecta) or super-extendable tissues (Ehlers-Danlos Syndrome). Altogether, collagen fibril mechanics can be seen as a multiparameter space that currently is only partially understood.
Insights into collagen fibril mechanics and tissue mechanics at the nano- and microscale levels are important for understanding changes due to age and disease. Mechanics in unison with analytical techniques can help uncover targets for diagnostics and treatment of pathologies. As cells sense their environment at the micro- and nanoscale, the insights gained are also useful in mechanobiology and can inform tissue engineering approaches.