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

Recent advance in surface modification for regulating cell adhesion and behaviors

“…Soft lithography (SL) is a micro-nano processing technology based on elastic seal printing [82,83]. Elastic seals with patterned relief structures are used to generate patterns and structures with feature sizes from 30 nm to 100 μm.…”

“…Soft lithography uses elastomeric stamp to replace hard stamp in traditional lithography to fabricate arrays of microstructures onto hydrogel surfaces (reproduced from ref [82]…”

Manufacturing micropatterned collagen scaffolds with chemical-crosslinking for development of biomimetic tissue-engineered oral mucosa

“…(A) 1% collagen scaffolds with 1% EDC crosslinking. www.nature.com/scientificreports/ micropatterns did not seem to have sufficient physical property to tolerate the mechanical forces during epithelial formation 39,40 . To manufacture a stiffer collagen scaffold, another approach, such as producing basement membrane-like structure or use of supramolecular cross-linkers, may be required to tolerate the mechanical force generated by cells, producing a stable microenvironmental cue 41 .…”

Formation of Stem Cell Aggregates and Their Differentiation on Surface-Patterned Hydrogels Based on Poly(2-hydroxyethyl Methacrylate)

“…The hydrogel micropillar arrays of different heights (2.05 and 4.91 μm) were prepared using PDMS molds: the negative replicas of original surface-patterned silicon wafers, using the previously described procedure. 25 The composition of the hydrogel was adapted from work published by You and Auguste. 26 In brief, the monomers HEMA, DMAEMA, and TEGDMA were mixed with the initiator 2-hydroxy-2-methylpropiophenone in a ratio of 38:2:1:1 mol/mol, respectively, and the solvent mixture containing water and ethylene glycol (1:1 mol/mol).…”

“…This is a continuation of our recent study where we showed the microfabrication of poly(HEMA/DMAEMA/TEGDMA) micropillar arrays from negative replicates of the original pattern on silicon wafers. 25 Pillars with 1 μm diameter and different heights were patterned as hexagonal arrays with a pitch of 3 μm. Pillars with two heights, 2.05 and 4.91 μm, were utilized to understand the effect of bending deflection on hMSCs within 24 h after seeding the cells.…”