Scientists grow elastic ear cartilage in the lab ^{CEFR B2}

Researchers from ETH Zurich, the Friedrich Miescher Institute in Basel and the Cantonal Hospital of Lucerne have produced elastic ear cartilage from human cells in the laboratory. The engineered cartilage shows mechanical properties close to natural tissue and was reported in the journal Advanced Functional Materials.

The team began with small cartilage remnants removed during corrective operations and expanded the cells in a nutrient solution. About 100,000 cells can be isolated from a piece roughly three millimetres across, yet a printed ear requires several hundred million cells. To address this gap they optimised cell proliferation, adjusted material properties and increased cell density while developing a culture environment that supplies nutrients and oxygen to the printed structure.

• Optimised cell proliferation
• Adjusted material properties
• Increased cell density
• Controlled the maturation environment

They tested growth factors to encourage cell division and to avoid cells turning into fibroblasts, which would form fibrocartilage rather than elastic cartilage. After about nine weeks of pre-maturation the constructs were implanted under the skin of rats and stayed stable after six weeks, though elastin did not mature fully. The experiments take roughly three to four months, and the team hopes to find the blueprint for the elastin network within the next five years before moving to clinical studies and formal approval.