An artificial heart made with a 3D printer uses air pressure to mimic the movements of the real organ and can one day be used to pump blood for people on heart transplant lists, potentially giving them more time to wait for a donor.

The soft device is made of silicone and has a left and right ventricle, the two main chambers of the heart that expand and contract to pump blood into the rest of the body. But instead of a section of tissue in between the ventricles called a septum, according to a study in the journal Artificial Organs, the 3D-printed heart has another chamber that itself expands and contracts through air pressure to get that pumping action going.

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“It looks like a real heart,” the Swiss university ETH Zurich explained. It also “fundamentally works and moves in a similar way to a human heart.”

So far, the researchers could only get the silicone heart to last for about 3,000 beats, which is the equivalent of half an hour to 45 minutes of service, before “the material can no longer withstand the strain,” the university said. But this concept holds some promise, if refined, for the millions of people around the world who need heart transplants, perhaps keeping them alive as they wait for a donor organ, or to help people whose hearts are recovering from heart failure.

silicone-heart An artificial heart made of silicone with a 3D printer uses air pressure to pump blood through its chambers just like a real heart. Photo: ETH Zurich

silicone-heart-3dprint Researchers have used a 3D printer to make an artificial heart out of silicone, and it shows promise for keeping heart transplant patients alive as they wait for donor organs. Photo: ETH Zurich

In the United States alone, there are about 4,000 people waiting on heart transplants, according to data from the U.S. Department of Health & Human Services. They are among the roughly 118,000 total people waiting on a transplant of any organ, with the greatest need being for kidneys, followed by livers. Another person is added to the national transplant waiting list every 10 minutes, and 20 people die every day before a replacement organ comes through.

The study says the artificial heart also needs design improvements to increase the blood flow. Still, “the preliminary results of this study show a promising potential of the soft pumps in heart replacements.”

Other devices that are currently used to keep cardiac patients alive are pumps made out of metals and plastics — materials that can cause issues for the patients. The silicone is friendlier to the body.

“Our goal is to develop an artificial heart that is roughly the same size as the patient’s own one and which imitates the human heart as closely as possible in form and function,” researcher Nicholas Cohrs said in the ETH Zurich statement.

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The 3D-printed heart is close to the same size and weight as an average human heart — it doesn’t even weigh a full pound.

“As a mechanical engineer, I would never have thought that I would ever hold a soft heart in my hands,” researcher Anastasios Petrou said in the statement. “I’m now so fascinated by this research that I would very much like to continue working on the development of artificial hearts.”