Stanford University scientists have created a method to 3D-print living heart tissue, potentially revolutionizing organ transplantation. The team, led by Mark Skylar-Scott, aims to print essential parts of the heart, such as ventricles and valves, that can grow with the patient.

In the US, one in 100 children is born with a heart defect, and while they can receive transplants, rejection can occur up to 30 years later. Bioprinting an organ from a patient’s own cells could significantly reduce these cases. 3D printing technology has already impacted industries such as automotive, housing, and food, and now it could revolutionize medicine as well.
The process of bioprinting involves using living cells to create structures similar to organs, and while it is not a new concept, it has traditionally been a slow process that involves printing cells one at a time. Even at a rate of 1,000 cells per second, it would take more than a millennium to print a single human heart.
However, a team led by Skylar-Scott has developed a method to accelerate the bioprinting process by using clusters of thousands of cells known as organoids. These organoids are condensed into a “human stem cell mayonnaise,” which can be printed through the printer for quicker and more efficient printing.
After printing, the cells assume a tissue-like form, which can accommodate the printing of blood vessels within them. A tube-like structure akin to a human vein has already been printed by the team, which can function as a pump for fluids. The team’s next objective is to print a larger structure, such as a functional chamber that can be grafted onto an existing heart.
Skylar-Scott is optimistic that a heart valve produced using this method could be transplanted into a human patient in as little as five years. However, it is anticipated that a fully printed heart is at least two decades away.