The Wake Forest Institute for Regenerative Medicine has built a 3D printer that makes human-sized muscle, cartilage, and bone that all grew and developed blood vessels after being implanted into mice.

A new method of 3D printing, which has been a decade in the making, can produce human-sized bone, muscle, and cartilage. And when implanted into mice and rats, the 3D-printed ear, cartilage and bone all grew and developed blood vessels. The 3D-printed skeletal muscle has similar results, contracting like developing muscle two weeks after implantation.

This 3D printing process, called the Integrated Tissue-Organ Printing System (ITOP), was developed by a team of researchers at the Wake Forest Institute for Regenerative Medicine. As outlined in the journal Nature Biotechnology, ITOP produces a network of tiny channels that allows the printed tissue to be nourished after being implanted into a living animal. As soon as more tests are conducted and researchers receive government approval, the technology will be tested on humans.

“The main goal is to scale up production of these tissues so they can be used in patients long-term,” Dr. Anthony Atala, director of the Wake Forest Institute for Regenerative Medicine and lead author of the paper, says in Nature Biotechnology.

This custom 3D printer uses bio-gel and biodegradable materials and can scan a blueprint, then create whatever is ordered. This isn’t the first bio-3D printer, however, but previous models were limited by the size of the tissue they could print. Atala writes that ITOP gets around the size limitation with a latticework of microscopic valleys into the bone, muscle, and cartilage it prints that allow nutrients and blood to flow in, keeping tissues alive for months before they’re implanted.

“The concept is, you would take a small piece of tissue from a patient – less than half the size of a postage stamp – then we can expand the cells outside the body and place them in the printer so we could print tissues for that same patient,” Atala says.

Completed ear and jaw bone structures printed with ITOP. (Photo Credit: Wake Forest Institute for Regenerative Medicine)

Atala said it takes several weeks to grow the cells and a few hours to print them. Part of the goal of this project is to grow replacement tissues and organs in the lab to offset the shortage available for transplants. Atala said the “goal is to treat patients and our wounded warriors.”

Dr. Lobat Tayebi from Marquette University School of Dentistry, Milwaukee, Wisconsin, who has also done bioprinting research, told Reuters that although ITOP’s approach has some challenges, it “can eventually be applied for producing reliable and robust bioprinted tissues.”

“There are numerous difficulties in bioprinting tissues in terms of robustness, integrity, and (blood vessel supply) of the end product. What is the most admirable about this study is the serious effort to overcome these problems by introducing an integrated tissue-organ printer (ITOP). This is a big step toward producing robust bioprosthetic tissues of any size and shape.”