Facile and Versatile Method for Micropatterning Poly(acrylamide) Hydrogels Using Photocleavable Comonomers.

We here present a micropatterning strategy to introduce small molecules and ligands on patterns of arbitrary shapes on the surface of poly(acrylamide)-based hydrogels. The main advantages of the presented approach are the ease of use, the lack of need to prefabricate photomasks, the use of mild UV light and biocompatible bioconjugation chemistries, and the capacity to pattern low-molecular-weight ligands, such as peptides, peptidomimetics, or DNA fragments. To achieve the above, a monomer containing a caged amine (NVOC group) was co-polymerized in the hydrogel network; upon UV light illumination using a commercially available setup, primary amines were locally deprotected and served as reactive groups for further functionalization. Cell patterning on various cell adhesive ligands was demonstrated, with cells responding to a combination of pattern shape and substrate elasticity. The approach is compatible with standard traction force microscopy (TFM) experimentation and can further be extended to reference-free TFM.