The extracellular matrix is a complex assembly of structural proteins that provides physical support and biochemical signaling to cells in tissues. Over the last decade, studies have revealed the important role that extracellular matrix elasticity plays in regulating a variety of biological processes in cells, including stem cell differentiation and cancer progression. However, tissues and matrix are often viscoelastic, exhibiting stress relaxation over time in response to a deformation. This talk will focus on our recent efforts to elucidate the viscoelastic properties of extracellular matrices, and then engineer new biomaterials for 3D culture in which the stress relaxation properties can be modulated independent of initial elasticity and cell adhesion ligand density. Using these materials, we find that the rate of stress relaxation regulates stem cell differentiation, cartilage matrix deposition by chondrocytes, and breast cancer cell invasion.
Our group's research is focused at the intersection of mechanics and biology. We are interested in elucidating the underlying molecular mechanisms that give rise to the complex mechanical properties of cells, extracellular matrices, and tissues. Conversely, we are investigating how complex mechanical cues influence important biological processes such as cell division, differentiation, or cancer progression. Our approaches involve using force measurement instrumentation, such as atomic force microscopy, to exert and measure forces on materials and cells at the nanoscale, and the development of material systems for 3D cell culture that allow precise and independent manipulation of mechanical properties.