Rapid and mass manufacturing of soft hydrogel microstructures for cell patterns assisted by 3D printing

Micro-/nano-patterns on hydrogels are widely used in cell patterning. However, manufacturing molds with traditional lithography is time-consuming and expensive. In addition, the excessive demolding force can easily damage patterns since biocompatible hydrogels are ultra-soft or brittle. Here, we presented a novel method for rapid and mass fabrication of cell patterns. High-precision three-dimensional (3D) printing was used to manufacture a mold with a resolution of 2 μm, and the gelatin-based hydrogel was cured by thermal–photo-crosslinking so that the low-concentration and low-substitution-rate hydrogel could be demolded successfully. We found that pre-cooling before illumination made gelatin-based hydrogels resilient due to the partial regain of triple-helix structures . With this method, arbitrarily customized hydrogel patterns with a feature size of 6–80 μm can be fabricated stably and at low cost. When cardiomyocytes were seeded on ultra-soft hydrogels with parallel groove structures, a consistent and spontaneous beating with 216 beats per minute (BPM) could be observed, approaching the natural beating rate of rat hearts (300 BPM). Overall, this work provides a general scheme for manufacturing cell patterns which has great potential for cell ethology and tissue repair. Graphic abstract