People who need heart transplants have a tough road ahead of them. There are fewer organs available for transplants than there are patients who need them. And if a person is lucky enough to receive a heart, she must undergo surgery and a lifetime of medication to keep her body from rejecting the organ.

“At the moment, transplant medicine dominates, but it would be much better to create tissue in the lab, with the patient's own DNA, so that the danger of tissue rejection is completely eliminated," said Marko Mihovilovic, a researcher at the Vienna University of Technology.

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Mihovilovic and his colleagues have patented a synthetic substance that turns embryonic and adult stem cells into heart cells that eventually start beating in a petri dish.

The scientists call the process modular and liken it to playing with LEGO bricks. Assembling one combination of chemicals works to differentiate stem cells into one type of organ, while assembling another combination works to differentiate the cells into another type of organ.

In general, heart tissue regenerates poorly. If this kind of synthetic chemistry works in a patient, using her own DNA to grow new heart cells, it could help improve her quality of life and at the same time reduce health-care costs.