Living skeletal muscle that not only functions like the real thing but can heal itself has been engineered by scientists.
The lab-grown tissue, produced from immature pre-cursor cells, was demonstrated in mice.
Scientists believe it marks a significant step towards growing viable replacement muscle in humans.
Unlike previous examples of bioengineered muscle, the artificially-constructed muscle fibres contracted as strongly as their natural counterparts.
Satellite cells - dormant step cells that can be activated by injury to regenerate damaged tissue - were at the heart of the self-repair mechanism.
The secret was supplying them with the right environment, the researchers writing in the journal Proceedings of the National Academy of Sciences said.
"Simply implanting satellite cells or less-developed muscle doesn't work as well," said Mark Juhas, a member of the team from Duke University in Durham, US.
"The well-developed muscle we made provides niches for satellite cells to live in, and, when needed, to restore the robust musculature and its function."
Stimulating the tissue with electric pulses to make it contract showed that the engineered muscle was more than 10 times stronger than any of its predecessors.