Multiscale Anisotropic Scaffold Integrating 3D Printing and Electrospinning Techniques as a Heart‐on‐a‐Chip Platform for Evaluating Drug‐Induced Cardiotoxicity

Cardiac safety assessments are significant in drug discovery, as drug-induced cardiotoxicity (DIC) is the primary cause of drug attrition. Despite heart-on-a-chip (HoC) technology becoming an increasingly popular tool for evaluating DIC, its development remains a challenge owing to the anisotropic cardiac structure of the native myocardium. Herein, an anisotropic multiscale cardiac scaffold is presented via a hybrid biofabrication method by combining 3D printing with electrospinning technology, where the 3D-printed micrometer-scale scaffold frames enable mimicking the interwoven myocardium anatomical structure and the branched-aligned electrospun nanofibers network is able to directionally guide cellular arrangements. The in vitro 3D bioengineered cardiac tissues are then fabricated by encapsulating three-layer multiscale scaffolds within a photocurable methacrylated gelatin hydrogel shell. It is demonstrated that such an anisotropic multiscale structure could contribute to enhancing cardiomyocyte maturation and synchronous beating behavior. More attractively, with the integration of 3D bioengineered cardiac tissues and a self-designed microfluidic perfusion system, a 3D anisotropic HoC platform is established for evaluating DIC and cardioprotective efficacy. Collectively, these results indicate that the HoC model developed by integrating the 3D bioengineered cardiac tissues could effectively recapitulate the clinical manifestations, thereby highlighting their efficacy as a valuable preclinical platform for testing drug efficacy and cardiotoxicity.