Digital Light Processing 3D Printing Enables Versatile Fabrication of Human Engineered Heart Tissues

Cardiac drug discovery requires in vitro models that mimic features of the native environment of the human heart. Engineered heart tissue (EHT) models recapitulate aspects of cardiac physiology but are limited by scalability, cost, and reproducibility. Here, we report a one-step method to fabricate hydrogel molds using digital light processing (DLP)-based 3D printing to support EHT formation by human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). DLP permits enhanced EHT design versatility (e.g., mold size, aspect ratio, stiffness), as well as scaling to accommodate high-throughput experiments without compromising EHT quality. Importantly, fabricated EHTs display expected improvements in maturity over 2D iPSC-CMs, including increased expression of fatty acid metabolism genes, increased myofilament protein density, and improved sarcomere alignment. Further, EHTs show a response to pathological cardiac stimuli (e.g., adrenergic agonism, increased stiffness), resulting in an increase in pathology-associated genes and activation of signaling cascades involved in pathological remodeling, compared to untreated controls or 2D iPSC-CMs. DLP 3D printing of EHT molds mitigates issues of EHT scalability, design versatility, cost, and batch-to-batch variability. These advantages elevate DLP-enabled EHTs as a model compatible with both mechanistic in vitro human cardiac tissue studies and large-scale drug screening.