Scientists have grown walnut-sized human livers and hope the technique can be used for transplantations. The research also opens the prospect of testing the safety of experimental drugs.
US scientists created the organs by sowing seeds of human cells onto scaffolds derived from animal livers. The original cells were then replaced with immature human liver cells before being fed nutrients and oxygen in a bio-reactor, The Telegraph reported.
The researchers said that after a week in the lab bio-reactor, the livers seemed to be growing and functioning like a normal human organ.
Pedro Baptista from the Wake Forest Institute for Regenerative Medicine in the US said: "Our hope is that once these organs are transplanted, they will maintain and gain function as they continue to develop."
The new research was presented on Saturday at the annual meeting of the American Association for the Study of Liver Diseases in Boston.
The next step, explained the researchers, is to see if the organs will continue to function after they have been transplanted into animals. Only then will it be possible even to consider their use in humans.
It could take five or more years for the technology to find its way from the lab into hospitals.
Earlier this year, US scientists at Massachusetts General Hospital in Boston reported using a similar scaffold technique to construct miniature rat liver grafts. They were able to transplant the organs into live rats, where they survived for several hours.