Levich Institute Seminar Announcement, 12/06/2016
Steinman Hall, Room #312
(Chemical Engineering Conference Room)
Professor Frederick MacKintosh
Chemical and Biomolecular Engineering Department
"Extracellular Matrix Rheology: Mechanical Phase Transitions and Anomalous Normal Stresses"
The mechanics of cells and tissues are largely governed by scaffolds of filamentous proteins that make up the cytoskeleton, as well as extracellular matrices of collagen. Evidence is emerging that such networks can exhibit rich mechanical phase behavior. A classic example of a mechanical phase transition was identified by Maxwell for macroscopic engineering structures: networks of struts or springs exhibit a continuous, second-order phase transition at the isostatic point, where the number of constraints imposed by connectivity just equals the number of mechanical degrees of freedom. We present recent theoretical predictions and experimental evidence for mechanical phase transitions in both synthetic and biopolymer networks. We show, in particular, excellent quantitative agreement between the mechanics of collagen matrices and the predictions of a strain-controlled phase transition in sub-isostatic networks. We also discuss recent theoretical and experimental work on anomalous negative normal stresses in biopolymer networks.
BRIEF ACADEMIC/EMPLOYMENT HISTORY
Professor MacKintosh received his Ph.D. in Theoretical Physics from Princeton University in 1989. Following a postdoctoral fellowship at Exxon Corporate Research, he began his academic career in the University of Michigan’s Physics Department, first as an Assistant and then Associate Professor. In 2001, he joined the Physics faculty of Vrije Universiteit in Amsterdam, as Professor of Theoretical Physics. In July, 2016, he joined the Chemical and Biomolecular Department at Rice University.
RECENT RESEARCH INTERESTS
Dr. MacKintosh’s research focuses on the fundamental material properties of biological and soft matter networks.