The first human vocal chords have been grown in the laboratory by a team of scientists at the University of Wisconsin-Madison. The international group published the work in Science Translational Medicine in November.
Human cells from donors were coaxed into becoming tissue that replicates vocal fold mucosa, which form flaps inside the human larynx. These vibrate to produce sound.
The cells, one from a cadaver and four from surgically removed larynxes, were grown for two weeks around a collagen scaffold structure until the folds were one millimetre thick and 16 millimetres long.
By blowing air along them inside an artificial windpipe the team produced a sound they describe as a “robotic kazoo”. In the body, vocal chords vibrate up to 1000 times per second.
Mouth and throat modulations are required alongside this to produce the recognisable sounds of speech.
This research could be used in future to restore the power of speech to people who have lost or damaged their vocal chords. Voice impairment of some form currently affects 20 million Americans.
Quoted in New Scientist, Prof Harald Ott, who developed the first lab-grown bio-limb for a rat, says “It shows we’re getting closer and closer to engineering clinically relevant tissues”. There is a call for customisable repairs for specific parts of the body.
As such medical applications become commonplace, how far can tissue engineering be pushed?
The editor of Science Translational Medicine reflects on the limits of the research - vocal chords are one thing, but the ability to sing well is another: “Adele’s lyrics would not elicit chills (or tears) without strategic pitch and harmonizing known as appoggiatura”.
Just as we auto-tune popstars today, could the singers of the future upgrade their vocal chords for a richer tone?
Image credit: epSos.de / flickr
New Scientist (November 18, 2015) Human vocal chords build from scratch in world first
Science Translation Medicine (November 18, 2015) Bioengineered vocal fold mucosa for voice restoration