Generation and Culture of Cardiac Microtissues in a Microfluidic Chip with a Reversible Open Top Enables Electrical Pacing, Dynamic Drug Dosing and Endothelial Cell Co-Culture

Cardiovascular disease morbidity has increased worldwide. Organs-on-chips and human pluripotent stem cell (hPSC) technologies aid to overcome some of the limitations in cardiac in vitro models. Here, a bi-compartmental, monolithic heart-on-chip device that facilitates porous membrane integration in a single fabrication step is presented. Moreover, the device includes open-top compartments that allow facile co-culture of hPSC-derived cardiomyocytes and human adult cardiac fibroblast into geometrically defined cardiac microtissues. The device can be reversibly closed with a glass seal or a lid with fully customized 3D-printed pyrolytic carbon electrodes allowing electrical stimulation of cardiac microtissues. A subjacent microfluidic channel allowed localized and dynamic drug administration to the cardiac microtissues, as demonstrated by a chronotropic response to isoprenaline. Moreover, the microfluidic channel can also be populated with human induced pluripotent stem-derived endothelial cells allowing co-culture of heterotypic cardiac cells in one device. Overall, this study demonstrates a novel heart-on-chip model that systematically integrates an open-top device with a 3D printed carbon electrode for electrical pacing and culture of cardiac tissues while enabling active perfusion and dynamic drug dosing. Advances in the engineering of human heart-on-chip models represent an important step towards making organ-on-a-chip technology a routine aspect of preclinical cardiac drug development.