3D printers capable of building an entire human heart may already be on their wayAs ambitious project aimed at replacing human organs is underway all around the world, scientists at the Cardiovascular Innovation Institute in Kentucky are working on designs for a 3D printer capable of recreating that most poetic of parts, the human heart.

Dr. Stuart Williams, Scientific Director of the project in Louisville, Ky., says his team is already well down the road to developing custom-built 3D printers capable of printing an entire human heart – right down to heart muscle, vessels, valves and tissues, and he says the organ will be "grown" and printed from fat stem cells taken directly from a patient's own body.

"We're building next-generation printers to build the heart from the bottom up," said Williams.

A Ph.D. in cell biology from the University of Delaware who did his postdoctoral training in pathology at the Yale School of Medicine, Williams founded the University of Arizona biomedical engineering program to create a research an educational link between the medical school and the college of engineering. He was selected as the scientific director of the CII in 2007 and now works on projects related to regenerative medicine and infection control.

A number of projects to 3D print various human tissues, like those in the liver and kidneys, have already found success, and most of those processes also use stem cells taken from fat or bone marrow as source material, but Williams and his team plan to use 3D printing to reproduce individual segments of what they're calling the "bioficial" human heart.

According to Williams, that approach could one day lead to scientists being able to print and assemble a fully functional heart – and all within a week's time.

Williams says it's all about discovering a way to reproduce the components of the heart and then assembling them in working order.

One stumbling block facing the scientists in their quest to re-create full-sized organs is finding a way to include the delicate networks of blood vessels and capillaries needed to serve those organs. Williams says 3D printing can be used to create blood vessels, and indeed, his team has already built large blood vessel networks for use in transplant surgery. He adds that the system is currently challenged beyond its capabilities when applied to the smallest-scale levels. As the smallest blood vessel may be just a few microns across, current technology in the hands of bio-engineers is only capable of creating much larger structures.

"We will be printing things in the order of tens of microns – or more like hundreds of microns – and then cells will undergo their biological developmental response in order to self-organize correctly," Williams said.