by Camila Domonoske

Vocal cords are small and complex — and, when badly damaged, they’re difficult to treat.

Now, scientists at the University of Wisconsin-Madison have engineered lab-grown vocal cord tissue for the first time.

The tissue appears to be functional, the researchers report, although so far it has only been tested outside of an animal’s body.

The Associated Press explains the researchers’ process:

Welham’s team started with some rare donations of vocal cords from four patients who had had their larynx removed for non-cancerous reasons, and from one deceased donor. The researchers culled two types of cells that made up most of the tissue, and grew a large supply of them.