Animal cells in tissues are supported by biopolymer matrices, which exhibit highly nonlinear mechanical properties. Here we show that this nonlinearity allows living contractile cells to generate a massive stiffness gradient in three distinct 3D extracellular matrix model systems: collagen, fibrin, and Matrigel. We decipher this remarkable behavior by introducing Nonlinear Stress Inference Microscopy (NSIM), a novel technique to infer stress fields in a 3D matrix from nonlinear microrheology measurement with optical tweezers. Using NSIM and simulations, we reveal a long-ranged propagation of cell-generated stresses resulting from local filament buckling. This slow decay of stress gives rise to the large spatial extent of the observed cell-induced matrix stiffness gradient, which could form a mechanism for mechanical communication between cells.

2:00 – 2:50 Contributed talks: Pierre Ronceray, Princeton University. 

https://mediaspace.gatech.edu/media/Perry+Ellis+-+PRonceray_SMF_20180419/1_mynq6f6u