A soft lithography method to generate arrays of microstructures onto hydrogel surfaces

ABSTRACT Materials bearing microscale patterns on the surface have important biomedical applications such as scaffolds in tissue engineering, drug delivery systems, sensors, and actuators. Hydrogels are an attractive class of materials that has excellent biocompatibility, biodegradability, and tunable mechanical properties that meet the requirements of the aforementioned applications. Generating patterns of intricate microstructures onto the hydrogel surfaces, however, is challenging due to properties such as the crosslinking density, low mechanical strength, adhesion, or chemical incompatibility of hydrogels with various molds. Here, we report the use of a soft lithography technique to successfully transfer arrays of micropillars onto a poly(2‐hydroxyethyl methacrylate)‐based hydrogel. The swelling of the hydrogel in solvents, such as phosphate‐buffered saline, deionized water, 60% ethanol, and absolute ethanol, facilitates the reproducible replication of the pattern. Furthermore, the micropillar pattern promotes the attachment of HeLa cells onto this hydrogel which is not inherently adhesive when unpatterned. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 1144–1157 Generating microscale features on soft hydrogels with high fidelity and reproducibility remains a challenge. This paper demonstrates the successful replication of micropillar patterns onto a poly(2‐hydroxyethyl methacrylate)‐based hydrogel using the soft lithography technique. The swelling of the hydrogel was utilized to make the pattern transferring process convenient and complete. The hydrogel was found to be non‐cytotoxic and the micropillar arrays facilitate the attachment of mammalian cells onto this intrinsically non‐adhesive material.