Surface-textured PEG-based hydrogels with adjustable elasticity: Synthesis and characterization.

Poly(ethylene glycol)-dimethacrylate (PEGDMA)-based hydrogels with adjustable shear modulus within the range of 10kPa to 1MPa and precisely predefinable surface textures on a micro-scale were made. It was observed that the volume of all hydrogels after preparation almost exactly matched the volume of the precursor solution and that there were only slight volume changes upon equilibration in excess solvent. This characteristic swelling behavior enables the preparation of textures on the hydrogel's surface with precisely predefinable dimensions. The behavior can be modeled with the Flory-Huggins theory assuming a concentration-dependent polymer-solvent interaction parameter. Additionally, activation of the hydrogels by electrophilic oxirane groups creates reactive sites that will enable the later grafting of the hydrogel's surface with various specific nucleophiles, e.g. biomolecules. Thus, these hydrogels are particularly suitable as biomaterials for systematic investigations of cellular response to surface topography and elasticity of the substrate, both in vivo and in vitro.