“There have been groups that have attempted to generate liver cells, and that’s been promising,” says Daley, who wasn’t involved in the current study. “This is the first attempt to regenerate the organ by mixing the cells that are critical components of that organ.”

Several labs around the world have been trying to grow organs on plastic scaffolds, which offer a three-dimensional surface on which cells can stick.

This approach has been used to make from a person’s own cells. And doctors have even transplanted these synthetic organs into a handful of patients.

But more complex organs – kidneys, pancreases and livers – have been elusive. So Takanori Takebe and a team at the Yokohama City University tried a more laid-back strategy: They let the cells build their own scaffold.