Molding Micropatterns of Elasticity on PEG-Based Hydrogels to Control Cell Adhesion and Migration

We present an innovative and simple, soft UV lithographic method “FIll‐Molding In Capillaries” (FIMIC) that combines soft lithography with capillary force driven filling of micro‐channels to create smooth hydrogel substrates with a 2D micro‐pattern on the surface. The lithographic procedure involves the molding of a polymer; in our case a bulk PEG‐based hydrogel, via UV‐curing from a microfabricated silicon master. The grooves of the created regular line pattern are consequently filled with a second hydrogel by capillary action. As a result, a smooth surface is obtained with a well‐defined pattern design of the two different polymers on its surface. The FIMIC method is very versatile; the only prerequisite is that the second material is liquid before curing in order to enable the filling process. In this specific case we present the proof of principle of this method by applying two hydrogels which differ in their crosslinking density and therefore in their elasticity. Preliminary cell culture studies on the fabricated elasticity patterned hydrogels indicate the preferred adhesion of the cells to the stiffer regions of the substrates, which implies that the novel substrates are a very useful platform for systematic cell migration studies, e.g. more fundamental investigation of the concept of “durotaxis”. An innovative and versatile soft lithographic method is presented, which is denoted FIMIC (FIll‐Molding In Capillaries). We have employed this method to fabricate smooth, hybrid surfaces with a micropattern of elasticity, using two hydrogel formulations with different crosslinking density. The hydrogels are prepared from PEG‐based macromonomers that are liquid before crosslinking, which is an essential requirement for the FIMIC process. The resulting hybrid hydrogels with micropatterns of elasticity represent a very useful platform to study cell motility in dependence of substrate rigidity, e.g. “durotaxis”. The first cell culture results show that the fibroblasts selectively move around on and eventually adhere to the stiffer regions.