Automated cell culture system for the production of cell aggregates with growth plate-like structure from induced pluripotent stem cells

Programmable liquid handling devices for cell culture systems have dramatically enhanced scalability and reproducibility. We previously reported a protocol to produce cell aggregates demonstrating growth plate-like structures containing hypertrophic chondrocytes from human induced pluripotent stem cells (hiPSCs). To apply this protocol to large-scale drug screening for growth plate-related diseases, we adapted it to the automated cell culture system (ACCS) consisting of programmable liquid handling devices connected to CO₂ incubators, a refrigerator, and labware feeders, designed for up to 4 batches with several cell culture plates culturing for several months. We developed a new program preparing culture media with growth factors at final concentration immediately before dispensing them to each well and precisely positioning the tip for the medium change without damaging cell aggregates. Using these programs on the ACCS, we successfully cultured cell aggregates for 56 days, only needing to replenish the labware, medium, and growth factors twice a week. The size of cell aggregates in each well increased over time, with low well-to-well variability. Cell aggregates on day 56 showed histochemical, immunohistochemical, and gene expression properties of growth plate-like structures containing hypertrophic chondrocytes, indicating proper quality as materials for basic research and drug discovery of growth plate related diseases. The established program will be a suitable reference for making programs of experiments requiring long term and complex culture procedures using ACCS.