Serological pipettes

iPSC‐derived cardiomyocytes were collected from the bioreactor on Day 14, washed with phosphate buffered saline (PBS)^−/− (ThermoFisherScientific) once and resuspended in Liberase solution (50 μg/ml; Roche) and incubated at 37°C for 30 min. The aggregates were triturated every 15 min using 10 ml serological pipettes (Corning). Following dissociation, an equal volume of growth medium (RPMI‐1640 + B27 with insulin) was added to the cell suspension to dilute the Liberase. The cells were centrifuged at 200g for 3 min at room temperature. Following centrifugation, the supernatant was removed and discarded. TrypLE solution was added to the cells and incubated for 7–8 min at 37°C. The enzyme was subsequently diluted by adding equal volume of growth medium. Viable cell counts were performed with the NC‐200 and the cells centrifuged at 200g for 3 min at 4°C. The supernatant was removed, discarded and the cell pellet was resuspended in CryoStor CS10 (BioLife Solutions) supplemented with 10 μM Y‐27632 at 5 × 10⁶ cells/ml. Cryovials (ThermoFisherScientific) were filled at 1.0 ml and cryopreserved using a Controlled Rate Freezer (ThermoFisherScientific).