Discovery Magazine

Understanding Bone Loss in microgravity through Nanoscale Finite Element analysis of Load bearing structures in Bone

It is well-known bones respond to stress but the mechanisms by which it occurs are very difficult to understand. This study will examine the structure of bone using atomic force microscopy and apply this data to the development of a finite element model of the process of loadbearing in bone. We will develop a geometric dataset to describe the osteon, a common structural component of bone, based on atomic force microscopy images.

In particular, we will examine the manner in which loads are transferred between the protein and mineral elements of bone and test a theory we have developed based on atomic force microscopy observations. This model must be based on what is known about the structural geometry and properties of bone at the nanoscale level, e.g. the properties of the collagen and mineral components in the pure state, including such properties as modulus of elasticity, Poisson’s ratio, ultimate strength, and what can be deduced from our observations from atomic force microscopy images regarding the structural organization of these components.

The model must explain, on the basis of theory and structure modeling alone, the behavior of bone at the macroscopic level, including ultimate strength, stiffness and impact resistance. This will be particularly critical for the transition from compact to trabecular bone. Finally, the model must predict the effect of changes in bone structure, including those changes seen in pathologic states and injury on these properties.