(Color online) Schematic of the molding process demonstrates the use of a PDMS stencil to obtain distinct, topographically patterned hydrogel regions. In the process, PDMS stencils were placed on PDMS stamps with ridge and groove features, where the pitches range from 400 to 4000 nm. Hydrogel precursor solutions were constrained within the void space of the stencil, covered with a treated glass cover slide and polymerized by exposure to UV light source. Discrete arrays of topographically molded hydrogels were then released from the elastomeric stamp and stencil.
(Color online) AFM measurements of the hydrated samples show the groove and ridge features molded into hydrogels with pitch sizes of 400, 1400, and 4000 nm. The difference in elevation from the ridge and groove is approximately 300 nm.
(Color online) (a) Fluorescence image of topographically molded hydrogel arrays functionalized with different concentrations of fluorescently tagged peptide. Rectangular or circular areas were spatially defined by a PDMS stamp, where the individual domains are isolated from the other regions. (b) Photograph of a rectangular topographically molded hydrogel array.
(Color online) hTCEpi cells migrate parallel to the pattern on both RGD (a) and AG73 (b) functionalized surfaces, where the arrow indicates the direction of the ridges and grooves. (c) The speed of cell migration was dependent on both the pitch of the topography and the biochemical cues of the peptide. (d)Similarly, the confinement ratio was also dependent on the pitch of the topography and the peptide. * is 0.01 ≤ p < 0.05, ** is 0.001 ≤ p < 0.01, and *** is p < 0.001 compared to the flat control (c) or the corresponding RGD gel (d).
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