Say you walk into a hospital today because your ear fell off. At the hospital, they would ask you if you had your ear with you. If you did, they might be able to sew it back on to your head. Otherwise, you'd probably be walking around for the rest of your life without an ear. The end.
However, a paper published this week in Nature Biotechnology might change all this. In your lifetime, science might be able to create whatever body part you want!
"The results of this study bring us closer to the reality of using 3-D printing to repair defects using the patient's own engineered tissue. It is often frustrating for physicians to have patients receive a plastic or metal part during surgery knowing that the best replacement would have been the patient's own tissue," says Dr. Anthony Atala, director of the Wake Forest Institute for Regenerative Medicine (WFIRM), via email.
3-D printing has been around for a while — for a few hundred dollars, you could go out today and buy a machine that could, using plastic resin, metal wire or even sugar as "ink," print a three-dimensional garlic press, wrench, or piece of candy. People have even built houses with 3-D printed parts. But the final frontier in 3-D printing has always been in creating living human tissue.
The researchers at Wake Forest Baptist Medical Center have successfully printed ear, bone and muscle tissue. So if science has printed tissue before — what's different about this?
The breakthrough here is that these researchers created a 3-D printer that can manufacture a tissue-like substance capable of hitching up with the body's own vascular system, which matures into something that passes as functioning tissue when attached to the body.
"This novel tissue and organ printer is an important advance in our quest to make replacement tissue for patients," says Atala in a press release. "It can fabricate stable, human-scale tissue of any shape. With further development, this technology could potentially be used to print living tissue and organ structures for surgical implantation."
Funded by Armed Forces Institute of Regenerative Medicine with the intention improving medical care on the battlefield, the research team worked for a decade developing the Integrated Tissue and Organ Printing System (ITOP). They discovered during these 10 years that squirting stem cells out of a machine similar to the ink-jet printer doesn't create a substance strong enough or similar enough in scale to actual tissue to be accepted by the human body.
What makes this particular printer and "ink" different from the previous attempts at creating replacement tissue is that it takes into consideration how delicate stem cells are, creating a biodegradable outer structures to protect the cells, which are suspended in a water-based ink specially formulated to hold cells in a way that will help them grow. The ink is printed into a “lattice of microchannels” so all the cells get the nutrients and oxygen they need while they're growing a network of blood vessels.
"Our results indicate that the bio-ink combination we used, combined with the micro-channels, provides the right environment to keep the cells alive and to support cell and tissue growth," says Atala.
The ITOP also takes into consideration that different structures have different sized blood vessels. For instance, a baby ear is going to grow a more delicate network of blood vessels than an adult ear, so the ITOP uses CT and MRI scans to figure out how to scale a custom-made tissue for each patient.
So far, this technology has only been used in lab rats, but the paper shows that ITOP was successful in making muscle tissue capable of growing blood vessels and nerves in two weeks. After five months, skull bone fragments implanted into rats had formed functioning bone tissue.
So congratulations, Van Gogh! We're one step closer to growing you a new ear, in case it ever comes up.