Biophysics Colloquium - Paul Janmey - University of Pennsylvania

Hosted by Mingming Wu

Title: Control of tissue, cell, and nuclear stiffness by filament networks and    particle inclusions

Abstract: Fibrous networks are ubiquitous in biology.   Collagen fibers form much of the extracellular matrix, the cytoskeleton controls cell mechanics, chromatin fibers span the volume of the nucleus, and various 2D networks line many cell membranes. The mechanical properties of the biopolymer fibers, the way in which the fibers are linked into networks, and the types of cells or particles within the network mesh all affect the macroscopic mechanical response of the material.   Filamentous polymer networks containing volume-conserving particles are found in the cytoskeleton and extracellular matrix of animal cells and tissues, bacterial biofilms, fungal mycelia, and other structures spanning multiple biological kingdoms.  The responses of biomaterials to uniaxial and shear deformations depends critically on the volume fraction of particles within networks and on the binding of particles to the network, but current data suggest that the mechanical properties of the particles themselves have only minor effects on the response of the composite material. Controlling biopolymer network connections and incorporation of appropriately sized particles within them can lead to viscoelastic properties that mimic those of biological tissues more closely than polymer networks alone. 

Poster