Wrinkled Hydrogel Surfaces with Modulated Surface Chemistry and Topography: Evaluation As Supports for Cell Growth and Transplant

We report a straightforward procedure to simultaneously functionalize hydrophobic PC supports with vinylpyrrolidone (VP)-based hydrogels with both variable ionic load as well as surface topography, forming wrinkles. The strategy involves three consecutive steps: first, a contact of the polymeric support (PC) with a photopolymerizable solution comprising vinylic monomers is established. Second, UV-light exposure curing of the solution and finally, the third step involes the swelling of the hydrogel network that finally provokes its surface detachment. Interestingly, a wrinkled hybrid PC/hydrogel interface remains after this detachment. Several experimental parameters permitted us to finely control the wrinkle characteristics such as amplitude and period. The experimental parameters that can be varied, herein we will focus on the variation of the elapsed time (i.e., time of contact between the support and the photosensitive monomer mixture, or the solvent (type and amount) included in the monomer mixture. Equally, the nature of the additional ionic methacrylate monomers (M) employed plays a key role on the final topography. According to confocal raman microscopy results, we evidenced that a monomer diffusion into the PC substrate before the UV irradiation step modifies the interfacial (hydrogel/substrate) chemical composition and leads upon UV irradiation to the formation of a thin hydrogel surface layer. The surface chemical composition and structural characteristics were demonstrated to significantly change the surface interaction with different cell lines, affecting cell adhesion, proliferation, or transplantation.