Automated Process Developed for Bulk Lung Organoid Production

A team led by Professor Diana Klein at the University of Duisburg-Essen has developed a straightforward automated method for producing human lung organoids in a stirred bioreactor. These miniature “mini lungs” contain many of the same cell types as real lung tissue and offer a more realistic alternative to conventional cell lines for studying lung disease and testing potential treatments.

Klein describes the key achievement simply: “The best result for now—quite simply—is that it works. This means that, in principle, lung organoids can be produced using an automated process. These complex structures represent the in vivo situation better than conventional cell lines and thus serve as an excellent disease model.”

The method starts with stem cells grown in culture dishes until they reach sufficient numbers. The cells are then detached, placed in anti-adhesive dishes to form floating aggregates known as embryoid bodies, and exposed to growth factors that are typically present in the lungs or during lung development. Under these conditions, the cells differentiate into various lung cell types.

To scale up production, the embryoid bodies are transferred into a bioreactor with a continuously stirring membrane and a suitable culture medium that supports organoid growth over four weeks. In parallel, the scientists manually generated a control set of lung organoids on standard culture plates. After the growth period, both groups of organoids were analyzed using microscopy, immunofluorescence, immunohistochemistry, and RNA sequencing to assess their structure and cell composition and to compare the automated method with the conventional approach.

The analyses showed that both automated and manual organoids formed lung-like airway and alveolar structures and developed characteristic epithelial and mesodermal lung cells. Although the same cell types appeared in both groups, their proportions differed somewhat: manually grown organoids contained more alveolar cells, while bioreactor-grown organoids tended to be larger with fewer alveolar spheres. Even so, Klein emphasizes that the organoids display “very good bronchiolar and alveolar structures” and that they are human-based models containing cells also found in patients.

The study, published in Frontiers in Bioengineering and Biotechnology, points to practical applications in high-throughput testing of potential therapies and in predicting patient-specific responses to treatments such as radiotherapy. At the same time, Klein notes that “organoids can’t yet fully recapitulate the lung cellular composition” because elements like immune cells and blood vessels are still missing. She adds that “there is still a lot of room for optimization” and calls for robust, scalable protocols that carefully consider bioreactor design, cell types, and culture conditions—but concludes, “we’re working on it!”