Colloquium: Untangling the Mechanics of Entangled Biopolymer Composites

Colloquium:  Untangling the Mechanics of Entangled Biopolymer Composites

Speaker:  Rae Robertson-Anderson, University of San Diego

Time: 2:00 p.m., Friday, February 15, 2019 (refreshments served at 1:45 p.m.) 

Place: P-148 

Abstract:  Biology naturally produces a wide range of polymers of varying stiffnesses and sizes, such as DNA, actin and microtubules. These ubiquitous biopolymers are often forced to function in highly concentrated environments and form composite networks by entangling with each other. Such networks display complex viscoelastic properties similar to those we find in the soft, squishy materials in and all around us. Our lab engineers molecular-level spectroscopy techniques and novel biopolymer composites to elucidate the macromolecular dynamics underlying the intriguing mechanics these networks display. We use optical tweezers to push and pull microspheres through the composites and measure the force the biopolymers exert to resist the strain. We also use fluorescence microscopy to characterize the macromolecular mobility and architecture of the composites. I will discuss three of our recent experiments that highlight these techniques and reveal fascinating impacts of macromolecular stiffness, interactions, and connectivity on the microscale mechanical response of entangled biopolymer composites.