2021/09/20 | Research | Biomechanics

Bone Mineralized Collagen Fiber Mechanics

Bone self-organization and deformation mechanisms are essential components for understanding and treating bone-related diseases. To explore the mechanical behavior of bone’s fundamental unit, the mineralized collagen fiber, researchers from the Heriot-Watt University in Edinburgh, UK, and the ARTORG Musculoskeletal Biomechanics group have conducted a collaborative nanoscale study. Financial support was provided by the EPSRC (EP/P005756/1), the ESRF and the Royal Society of Edinburgh (RSE).

The study aimed at developing a model that captures the compressive elasto-plastic behavior of a mineralized collagen fiber, a composite of organic collagen molecules and inorganic mineral nanocrystals. The team devised a novel experimentally informed statistical elasto-plastic model to explain the fiber behavior including the nanoscale interplay and load transfer with its main mechanical components. Experiments included nanometer length-scale imaging of the fibers at Europe's largest synchrotron light facility, the European Synchrotron Radiation Facility (ESRF) in Grenoble, France (cp. illustration).

Results reveal mechanisms such as micro- and nanoscale heterogeneity that give bone its ductile behavior. Results further indicate that interfibrillar shearing supports this post-yield ductility. The model incorporates crystalline-, molecular- and tissue-levels, closing an important gap in the theoretical understanding of these tissues. It can be generalized towards other fibril-matrix reinforced (bio-)composites to shed light on characteristic features in their micro- and nanoscale mechanical behavior.