Surgeons have performed the first transplant operation using an organ wholly grown in a laboratory to give a man a new windpipe.
The 36-year-old is recovering after surgeons implanted the world's first wholly lab-grown organ into his body.
The synthetic trachea was created by growing the patient's own stem cells on an artificial "scaffold", which British scientists helped design.
Windpipes have been grown from stem cells before, but only using the collagen "skeletons" of donated tracheas.
The landmark operation at Karolinska University hospital in Sweden could mean patients may not have to wait for a suitable donor organ. This could be particularly significant for children, for whom donor tracheas are much more difficult to find.
The patient, an African student living in Iceland, had been suffering from life-threatening tracheal cancer.
Professor Paolo Macchiarini, an Italian expert in regenerative medicine who led the groundbreaking operation, designed the Y-shaped synthetic trachea scaffold with Professor Alexander Seifalian, from University College London.
The Y-shaped structure was made from a plastic-like "nanocomposite" polymer material consisting of microscopic building blocks.
Two days after stem cells were placed into the scaffold they had grown into tracheal cells ready for transplantation.
Since the organ was built from cells originating from the patient, there was no risk of it being rejected by his immune system.
Prof Seifalian said: "What makes this procedure different is it's the first time that a wholly tissue-engineered synthetic windpipe has been made and successfully transplanted, making it an important milestone for regenerative medicine. We expect there to be many more exciting applications for the novel polymers we have developed."
The patient is said to be doing well and is due to be discharged from hospital today.