Microwrinkled pH-sensitive hydrogel films and their role on the cell adhesion/proliferation

In this work, hydrogels based on HEMA and DMAEMA (pH-sensitive monomer) were used to form biocompatible films which present microwrinkled patterns in their surface, with the focus of exploring the role of chemical composition on cell adhesion and proliferation. Three different pH (5.4, 7.4, and 8.3) were employed to prepare these hydrogels. The pre-polymerized hydrogel mixtures were deposited via spin coating, then exposed to vacuum for deswelling the films and finally, to UV-light to spontaneously generate the wrinkled pattern. By following this procedure, is possible to form a thin rigid layer on the top of the soft and incompletely polymerized hydrogel film which generates, in turn, a wrinkled pattern due to strain mismatch in the interface. FE-SEM and AFM micrographs allowed us to characterize the wrinkled pattern dimensions. The results evidenced that chemical composition is directly related to the surface pattern morphologies obtained, not so in the case of pH variation, which does not generate relevant changes in the pattern morphology. Interestingly, these pH variations resulted in significant alterations on the interface-cell interactions. More precisely, a premyoblastic cell monolayer was cultured over the wrinkled pattern, showing an optimal cell proliferation at neutral pH. Also, the variation of DMAEMA amount on the monomer feed composition employed for the preparation of the wrinkle surfaces revealed that a certain amount is required to favor cell attachment and growth.