Regulation of Cell Adhesion on Physically Crosslinked Hydrogels Composed of Amino Acid-Based Polymers by Changing Elastic Modulus Using Shape Fix/Memory Properties

The elastic modulus of hydrogels is one of the most important factors for controlling cell fate. In this study, hydrogels composed of poly(N-acryloylglycinamide) (PNAGAm) grafted with arginine (R)-glycine (G)-aspartic acid (D)-serine (S) peptide is designed without a chemical crosslinker. The hydrogels are prepared by the conventional radical copolymerization of N-acryloylglycinamide with a polymerizable RGDS peptide. The peptide grafting ratio is easily controlled by adjusting the feed composition for polymerization. The hydrogels exhibit thermo-responsiveness of the upper critical solution temperature type based on the PNAGAm moiety. This characteristic reflects the shape fix/memory properties of hydrogels because of the reversible formation of multiple hydrogen bonds. The cell adhesiveness of the hydrogels drastically improves in the presence of a small amount of the peptide graft. The hydrogels exhibit good biocompatibility; the adhered cells proliferate on the hydrogels, and macrophages do not show activation or inflammation. Surfaces with different elastic modulus regions are successfully constructed on the same hydrogel by using shape fix/memory properties, allowing the regulation of cell adhesion. This hydrogel system offers promising opportunities for the design and application of functional cell scaffolds. In this study, the physically crosslinked hydrogels composed of amino acid-based polymers are prepared, which exhibited shape fix/memory and cell adhesive properties. By using the shape fix/memory property, surfaces with different elastic moduli composed of the same hydrogel are successfully constructed, which enables control of cell adhesion and extension behaviors. image