(406g) Photopatterning Hydrogel Biomaterials with Site-Specifically Modified Bioactive Proteins

Polymer-based hydrogels have emerged as a unique class of biomaterials that enable stem cells to be cultured in three-dimensions within near-physiological, synthetic microenvironments. Recently developed strategies permit user-defined spatiotemporal introduction of bioepitopes to control cell function within subvolumes of the bulk material. Though such initial attempts have proven successful in the tethering of small molecules and short synthetic peptides within 3D culture platforms, there is a growing interest to direct cell fate through the patterned immobilization of full-length proteins. The high degree of protein-substrate specificity, as well as their ability to modulate complex cellular behavior (e.g., stem cell differentiation, protein secretion, and cell-cell interactions) generally exceeds that from simple chemical moieties. In this work, we demonstrate that site-specifically-modified proteins can be immobilized within a 3D material using a bioorthogonal light-based chemistry. As the exact residue of protein conjugation to the material can be explicitly defined a priori, proteins maintain wild-type levels of bioactivity and substrate specificity throughout modification and usage. Results further highlight the versatility of such dynamic biochemical signal presentation to probe and direct changes in cell fate.