Hard Tissue Biomechanics and Bone Degradation in Aging

We have taken a similar approach to studies of bone fracture and osteoporosis. Again, here the ultrastructure composed of collagen, mineral, water and the respective interactions creates a load carrying biomaterial. Its degradation in the aging population has widely been acknowledged as a major health concern. Our experimental and multi-scale mechanics analyses again connect the tissue ultrastructure and bone biomechanical function. This allows for insight into the connection of tissue level changes with aging, hydration and drug treatment in relation to bone strength and toughness. The multi-scale mechanics approaches developed in the recent past have proposed a new hypothesis for bone degradation in which bone mineral density alone no longer serves as the characterizing risk parameter, but molecular diagnostics on collagen crosslinking, in-vivo bone biomechanical testing, and bone microstructure from tomographic imaging are merged to not only more accurately assess fracture risk, but also to establish new therapeutic guidelines and insight into how therapeutic compounds actually affect bone strength.

Collaborators: M. Allen, J. Wallace, D. Burr, M. Allen, IU School of Medicine

Support: NSF

Bone Images


Biomechanics of Phonation

Our research aims to apply engineering mechanics methods to the understanding of problems in the biomechanics of soft and hard tissue.


 Soft Tissue Biomechanics and the Mechanics of Speech

Soft tissues derive their mechanical properties from the interaction between collagen, elastin, the cell cytoskeleton, water, and the adhesion processes between these constituents. Organ function depends on the organization of the molecular tissue components, but the connections between tissue ultrastructure and organ function are often unknown. In my research group we have investigated one particular human organ, the vocal fold system, as an example with complex biological function.  From our research we now can draw clear connections between tissue microstructure and speech function, allowing us to understand changes to phonation with aging and lifestyle choices, and to connect function to the molecular structure. We employ conduct quantitative histological studies on collagen microstructures, define hyperelastic-large strain viscoplastic constitutive equations, and employ information from such models to structural vibration models and to flow structure-interaction computations. Therapeutic approaches to remediation of phonation remain challenging, but our biomechanics insights have the promise to create individualized therapy by combining information of tissue ultrastructure, MRI generated subject specific phonation models and acoustics. 

Collaborators: RW. Chan, UT Southwestern Medical Center;

Funding: NIH