3D Bioprinting of Elastic Ear Cartilage

There is a widespread belief that we are on the verge of 3D printing functional organs, but the reality in the lab is far more complex. Although that goal remains distant, a team of researchers at ETH Zurich has reached a milestone that brings it closer. They successfully created elastic, stable ear cartilage from human cells grown in the lab. Led by researcher Philipp Fisch and Professor Marcy Zenobi-Wong, the team developed a 3D-printed artificial ear that retained its shape and mechanical properties after implantation in animal models, bringing personalized solutions for patients with severe malformations or injuries one step closer.

The main objective of this research is to overcome the limitations of current reconstruction methods. Today, the standard treatment for ear malformations or ear loss caused by accidents involves harvesting cartilage from the patient’s own ribs to sculpt a new ear. In addition to being painful, this method often results in an ear that is stiffer than a natural one. For this reason, scientists are working to create a tissue that offers the necessary stability and flexibility before being implanted in the human body.

Schematic overview of the ear cartilage manufacturing process (credits: P. Fisch, S. Kessler, S. Ponta, et al.).

To obtain the necessary biological material, the researchers extracted cells from small cartilage fragments left over from previous surgeries performed on other patients. From a tiny sample measuring just three millimeters, they initially isolated about 100,000 cells, which they then grew in a special nutrient solution until reaching the hundreds of millions needed to create a complete ear. During this cultivation process, the team optimized the environment to ensure that the cells produced type II collagen and elastin, both characteristic of ear cartilage, rather than turning into fibroblasts, which would produce much softer scar tissue.