Figure 1. Contiguous substrate with regions of dissimilar stiffness.
(a) Schematic describing the fabrication steps of mPA substrates of heterogeneous stiffness through modular polymerization of PA solutions of distinct compositions, resulting in dissimilar ECM stiffness in adjoining primary and secondary regions. (b) Atomic Force Microscopy (AFM) measurements of Young’s Modulus of PA gels plotted in logarithmic scale at different locations within a substrate with dissimilar primary and secondary ECM regions. Stiffness values are averaged over 1mm length intervals and plotted along with scattered data points and error bars (SEM). N>150. Data is included from at least 3 different PA gels, in which the left side was intended to be stiff (acrylamide/bisacrylamide=12/0.6%) and right side as soft (acrylamide/bisacrylamide=4/0.2%) matrix.