A 3D hydrogel scaffold with adjustable interlayer spacing for the formation of compact myocardial tissue

The design and optimization of three-dimensional tissue scaffolds have presented a persistent challenge for myocardial tissue engineering. While current scaffolds have made strides in mimicking in vivo three-dimensional environments, the presence of interlayer spacing has limited the formation of densely packed tissue, impeding cell-to-cell connections. We proposed a novel dynamic three-dimensional myocardial tissue engineering scaffold with adjustable interlayer spacing, aiming to improve the uniformity of cell distribution and facilitate effective cell communication. The device was composed of hydrogel scaffolds that were fabricated with poly (ethylene glycol) diacrylate (PEGDA) and flexible elastomer actuators that composed of polyurethane acrylate (PUA). Human induced pluripotent stem cell-derived cardiomyocytes mixed with gelatin methacryloyl (GelMA) were seeded onto the multi-layered scaffold with initial spacing of 100-500 mu m. Experimental results indicated the seeding efficiency was maximized at an initial spacing of 400 mu m. By decreasing the interlayer spacing, cell growth morphology and gap junction protein expression was improved. This work demonstrated the effect of interlayer spacing modulation to the tissue density and provided a potential approach for cultivation of compact and multi-layered myocardial tissue.