Industrialization of 3D hiPSC-cardiac microtissues for high-throughput cardiac safety and drug discovery screening

: Current cardiac cell models for drug screening often face a trade-off between cellular maturity and throughput. 3D human-induced pluripotent stem cell (hiPSC)-based heart models typically exhibit adult-like features, but their use often requires large cell numbers or complex equipment. In this study, we developed cost-effective methods to scale the production of stem cell-derived cardiac microtissues (cMTs) containing three cardiac cell types and assess calcium transients and action potential metrics for high-throughput screening (HTS). Automating the procedure revealed reproducible drug responsiveness and predictive accuracy in a reference compound screen. Furthermore, an arrhythmic phenotype was reliably triggered in cMTs containing cardiomyocytes with an RYR2 mutation. Screening a library of more than 2000 compounds demonstrated the suitability of the assay for identifying potential antiarrhythmic agents. Our findings underscore the scalability of cMTs and their utility in disease modeling and HTS. The advanced technology readiness level of cMTs supports their regulatory uptake and acceptance within the pharmaceutical industry.