Digital light processing 3D printing enables versatile fabrication of human engineered heart tissues

Investigations into cardiac biology and drug discovery benefit from in vitro models that replicate human cardiac physiology. Current engineered heart tissue (EHT) models recapitulate aspects of this physiology but are often limited by scalability, cost, and reproducibility. We report a one-step method to fabricate hydrogel molds using digital light processing (DLP) three-dimensional (3D) printing to support EHT formation from human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). DLP enables rapid tuning of mold size, aspect ratio, and stiffness while increasing scalability for high-throughput experiments without compromising EHT quality. DLP-fabricated EHTs show aligned extracellular matrix and display improvements in maturity versus two-dimensional (2D) cultures, including a shift to fatty acid metabolism, increased myofilament density, and improved sarcomere organization. These EHTs also display expected responses to pathological stimuli (e.g., adrenergic agonism, increased stiffness), enabling disease modeling applications. Overall, 3D DLP-printed EHT molds provide versatile, scalable cardiac tissue platforms for both mechanistic studies and large-scale drug screening.