Inside a lab that will open in a couple of months in Chicago, a biotech startup will soon begin perfecting the process of 3D-printing human hearts that could eventually be used in transplants.

“What this is set up to do is to make a patient-specific, fully functioning heart that’s viable for transplant, using the patient’s own cells,” says Steven Morris, founding partner and CEO of the startup, Biolife4D.

The process combines several steps that have been developed by various researchers in university labs. First, a patient’s heart will be scanned using an MRI machine to create a digital image of the heart’s shape and size. Next, doctors will take a blood sample. Using techniques that have been developed over the last decade, the blood cells will be converted into stem cells–and then converted a second time into heart cells. Those new heart cells will be combined with nutrients in a hydrogel to make a “bio-ink” that can be used in a specialized 3D printer.

Printing one layer at a time, with a biodegradable scaffolding to keep everything in place, the cells can be formed into the exact shape of the patient’s original heart. The new heart will be moved to a bioreactor to strengthen it. Amazingly, new heart cells outside a body will begin to self-assemble.

“When we’re done ‘bioprinting,’ we have something that looks like a heart, but it’s just individual cells in proper places,” says Morris. “Within a couple of days, the cells just know . . . ‘I’m a heart cell, you’re a heart cell, we’re supposed to join together and start beating.’ And they do that.”

When the heart is strong enough, technicians will raise the temperature to melt the scaffolding around the cells. The new heart can then be transplanted–and because it is the exact size of a patient’s original heart, and made from the patient’s own cells, it has a greater chance of success than a traditional transplant. In studies, other researchers have successfully transplanted stem cells in both humans and animals without the need for anti-rejection drugs.

Most people who receive heart transplants now don’t live more than a decade. Their body may reject the organ directly. The drugs they take to suppress their immune system–in an attempt to prevent the body from rejecting the foreign organ–may also make them unable to fight off another disease, such as cancer. The Biolife4D heart, in contrast, won’t require patients to take immunosuppressant drugs since it is an exact genetic match.