Tuesday, August 29, 2017 at 12:20pm to 1:45pm
Clark Hall, 700
M. Lisa Manning, Department of Physics, Syracuse University, Syracuse, NY, will present seminar. Professor Itai Cohen, host.
Seminar Title: Weird properties of biological matter
Abstract: Many tissues in your body are composed of tightly packed, or confluent, cells. The mechanical properties and dynamical behavior of these "materials" help govern important processes such as embryonic development, wound healing, and cancer progression, and so our goal has been to develop tractable models that make accurate predictions for these properties. A happy surprise is that these models exhibit rich and unexpected physics. For example, we have discovered that they exhibit a continuous rigidity transition governed by a purely geometric minimal surface criterion, which is qualitatively different from constraint counting arguments that ubiquitously explain rigidity in normal particulate matter. These models also have weird surface tension properties -- when probed mechanically, interfaces between two tissue types behave just as predicted from equilibrium stat mech, but the interfaces are orders of magnitude sharper than expected from standard capillary wave arguments. We now understand that this sharpness is a special feature generated by the topological nature of the cell-cell interactions. I will also touch upon other interesting phenomena, including a flocking fluid phase, spontaneous cellular streaming in heterogeneous mixtures, and implications of this physics for cancer, asthma, and organ formation in embryos.