The research objective of this project is to characterize the microscale mechanical behavior of bone tissue. Bone is a hierarchically structured material with organization levels ranging in size from nanometers to millimeters. Composition and microstructure vary with age and disease. The majority of work to date on mechanical characterization of bone has focused on macroscale properties (e.g. millimeter-centimeter scale), and little is known about the intrinsic mechanical properties of the mineralized tissue that constitutes the building block of bones. This research project characterizes these properties by applying micromachining techniques to isolate specific microstructural components, which are then tested in simple compression. Micropillars ranging in size from hundreds of nanometers to tens of microns are produced by femtosecond laser ablation and focused ion beam micromachining techniques and then tested using a modified nanoindenter. The results of the mechanical tests will be used to develop micromechanical models of bone fracture.
The results of this research project will establish an experimental approach for micro- and nanoscale mechanical characterization of a tissue whose mechanical function is critical for musculoskeletal health. These methods will complement existing techniques for studying age- and disease-related changes in bone composition and microstructure by providing a means of determining how these changes affect bone mechanical properties at the same length scale as the changes themselves. This research project will also focus on professional preparation of young scientists and engineers. Undergraduate and graduate students will participate directly in the research activities. The research activities will also be incorporated in courses and outreach events that expose pre-college and non-technical students to the field of materials science and engineering.
