The research objective of this award is to apply an emerging dynamic nanoindentation method to bone so that age- and disease-related changes in the viscoelastic behavior of the tissue can be quantified at the micron length scale for correlation with its fracture behavior. The organization of the primary constituents of bone is inherently hierarchical, and as such, each level contributes to the ability of bone to resist fracture. Dynamic nanoindentation and R-curve testing will be conducted at the level of the lamellae and at the level of the osteonal structure using cortical bone from young and old human donors, rodent models of disease, and bone whose properties have been altered ex vivo. In addition, the compositional characteristics of the bone will be measured to assess their relative contribution to the viscoelastic properties and fracture toughness.
This work has the potential to demonstrate that aging and certain diseases such as diabetes cause bone to dissipate less energy by suppression of viscous mechanisms at the tissue-level, thereby contributing to an overall reduction in the fracture resistance of bone. Moreover, the research will introduce a new set of tools for investigating the small-scale deformation behavior of biological tissues. The scientific knowledge generated from this program will enhance efforts in the field to develop hierarchical models of bone quality and to identify new therapeutic targets for fracture prevention. The project brings together an engineering and medical school multidisciplinary team, providing the opportunity for cross-fertilization of expertise from researchers in materials science and biomedical engineering. The educational plan focuses on opening pathways for engineers to make an impact on medical research and biomedical researchers to benefit from experimental approaches developed in the physical sciences.
