In 2011, an Eritrean man named Andemariam Teklesenbet Beyen was dying from tracheal cancer. The tumor in his windpipe was, the doctors explained, too big to remove. There was no time to wait for a donor organ to show up.

In years past, this might have been the end of the line for Beyen. Instead, he received a healthy new windpipe, made from his own cells. Beyen was the first of eight patients to receive a trachea grown on synthetic scaffolding in a laboratory. And so far, just two have died, from causes unrelated to their transplants. Harvard Apparatus Regenerative Technology, the regenerative medicine company behind many of the innovations used in the trachea transplants, believes we’re only seeing the beginning of the lab-grown organ industry.

I know it sounds all kinds of science-fictiony.

“We make regenerated organs for transplant. I know it sounds all kinds of science-fictiony. I think we’ve proven with the trachea that this approach works,” says CEO David Green.

HART, a spinoff from Harvard Bioscience, sees a booming business in lab-grown organs. Green estimates that there is a $600 million per year revenue opportunity for trachea transplants alone. “The major technological hurdles have been overcome. Now the main issues are regulatory,” he says.

The technological hurdles may have been overcome, but growing a trachea in a lab and then putting it inside a patient is no small feat. First, stem cells have to be taken from the patient. Then, they’re added to a scaffold tailored to the dimensions of the patient’s trachea. The scaffold is made out of a thin, styrofoam-like plastic polymer (HART doesn’t use donor tracheas as natural scaffolding, even though this is technically possible, because plastic ones can be made in unlimited quantities and don’t require immunosuppressant drugs).

The major technological hurdles have been overcome. Now the main issues are regulatory.

Two days before transplant time, the scaffold is seeded with the patient’s cells inside a rotating bioreactor, which offers ideal growing conditions for the new trachea.

Green believes this technique can be used in other hollow organs, like blood vessels, the small intestine, and the esophagus. But solid organs, like the heart, lungs, and kidneys, are more complex. And science isn’t even close to having lab-grown hearts and lungs available for patients (though scientists are certainly working hard to make that a reality).