The Protein Mat(ters) - Revealing Biologically Relevant Mechanical Contribution of Collagen and Fibronectin Coated Micropatterns

Understanding cell-material interactions requires accurate characterization of substrate mechanics, which are generally measured by indentation-type atomic force microscopy. Although model extracellular matrix coatings are used to facilitate cell-substrate adhesion, their tensile mechanical properties are generally unknown. In this study a novel tensile mechanical characterization of collagen and fibronectin micropatterned polyacrylamide hydrogels is performed. Our findings reveal that the protein coating itself has measurable and biologically relevant consequences, with ligand-specific tensile resistance of the patterned regions relative to the non-patterned surfaces. To our knowledge our study is the first to uncover a direction-dependent mechanical behavior of the protein coatings and to demonstrate that it affects cellular response relative to substrate mechanics.