Elasticity and breakdown of soft biological tissues

Bela Suki, Department of Biomedical Engineering, Boston University

In diseases, various biochemical processes alter the composition and mechanical properties of soft biological tissues. We developed experimental systems to measure the stress-strain and failure properties of tissues while simultaneously imaging the underlying structure. The results provide evidence that failure of collagen contributes to the progressive nature of pulmonary emphysema. We also developed elastic network models of lung tissues and tissue engineered materials. Using percolation, we demonstrate how the progression of disease processes such as fibrosis or emphysema can be better understood. Specifically, the global elastic properties of the network can be linked to percolation of local lesions such as clusters of stiff regions in fibrosis or clusters of failed regions in emphysema. Additionally, we will demonstrate how the inverse process of percolation, whereby a percolating cluster is broken down to a set of isolated clusters, can be used as a guiding principle in functionally efficient tissue engineering.