Event
Bioengineering Seminar Series: Jeffrey Urbach
Friday, November 12, 2010
11:00 a.m.-12:00 p.m.
Room 2108, Chemical and Nuclear Engineering Bldg.
Professor Helim Aranda-Espinoza
helim@umd.edu
Mechanics of Biopolymer Networks and Implications for Axon Growth
Jeffrey Urbach
Professor
Department of Physics
Georgetown University
Networks of relatively stiff filaments are responsible for many of the mechanical properties of cells and tissues, as well as many important synthetic materials. Unlike conventional gels, these materials are not well described by existing continuum theories based on the physics of flexible polymers. The mechanics of many biopolymer networks is strikingly nonlinear—the gels stiffen when subjected to applied shear. I will present recent experimental results showing that the nonlinear behavior is strongly dependent on the gel thickness, even at sizes that would normally be considered macroscopic. I will also present results from direct imaging of network rearrangements that provide some evidence for the mechanisms of strain stiffening. Finally, I will discuss the interaction between mechanical properties and cell motility, specifically in the context of axons extending from nerve cells. We find that the mechanical forces between axons and their environment, and the corresponding sensitivity to matrix stiffness, differs dramatically for different neuronal cell types.
