Modern medicine has come a long way over the last few decades, internist and gastroenterologist Dr. Roshini Raj says, but not much has changed when it comes to organ transplants — until now. 

"[Organ donation] is an area of medicine [where] we really need innovation," she says. "If you think about all those people waiting for organs, and some of them don't make it unfortunately. Now, we have this concept of 3D printing."

Can you 3D print organs?

"We're actually able to 3D print human organs made out of human cells," Dr. Raj explains.

How does 3D printing organs work?

"You're using human cells as ink in the printer. It's going to print a heart," the doctor explains. 

Watch the video above to see a printer in action, courtesy of biolife4D.com.

Cells in the body have the same number of genes and the same composition, so stem cells taken from blood samples can be converted to cells of another organ, like a heart, Dr. Raj explains. Those heart cells are loaded into a 3D bioprinter, and the organ is printed one layer at a time. 

"[Once printed], this heart, which is made out of cells, is put into a bioreactor [and] surrounded by fluids that actually make it grow into the heart tissue."

Incredible — but not so fast.

"[The first 3D heart] hasn't been grown into a life-sized functioning heart right now, but they have actually made a smaller version of it," Dr. Raj explains. "They've actually had a heartbeat — not life-sized yet, but still, it's an amazing technology." Wow!

"I think it's probably in the next few years that we're going to see this," she predicts, adding that heart valves have already been printed.

Watch the video above to see the example of a 3D-printed heart that Dr. Raj brought, courtesy of Loop Lab.