Fast and robust fabrication of reusable molds for hydrogel micro-patterning.

Mechanical interactions between cells and their microenvironment are crucial for fundamental biological processes ranging from migration to differentiation. This has led, over the last decades, to the development of new ways to culture cells. Living cells are now grown not only on glass coverslips, where they completely lose the mechanical and geometrical constraints coming from their microenvironment, but also on soft patterned substrates that mimic the rigidity and spatial information of their in vivo niches. Microfabrication processes have thus logically emerged has new tools to create model environments to probe the behavior of biological objects. Here, we present a method for fast and robust protein micropattern transfer onto polyacrylamide hydrogels that can be used for traction force microscopy. The technique relies on the elaboration of glass templates bearing patterned polymer brushes, which can be re-employed several times for the production of patterned gels without the need to repeat the critical microfabrication steps.