A team of biomedical researchers at Wake Forest Institute for Regenerative Medicine has just completed an invention 10 years in the making. It’s a 3D printer that can craft relatively simple tissues like cartilage into large complex shapes—like an infant’s ear. Using cartridges that are brimming with biodegradable plastic and human cells bound up in gel, this new kind of 3D printer builds complex chunks of growing muscle, cartilage, and even bone. When implanted into animals, these simple fabricated tissues survive and thrive indefinitely.
“THIS IS THE FIRST BIOPRINTER THAT CAN PRINT TISSUE AT THE LARGE SCALES RELEVANT FOR HUMAN IMPLANTATION.”
“This is the first [bioprinter] that can print tissue at the large scales relevant for human implantation,” Atala says. “Basically, once we’ve printed a structure, we can keep it alive for several weeks before we implant it. Now the next step is to test these [printed tissues] for safety so we can implant them in the future in patients.”
Blood and Plasti
To those familiar with 3D printing, Atala’s new device—named the Integrated Tissue and Organ Printing System, or ITOP—is straightforward. The programmed printer slowly squirts out layer upon layer of a rapidly hardening material in the form of tiny droplets. Like other 3D printers, this layered approach allows ITOP to print highly complex shapes in three dimensions with incredible detail. The materials ITOP uses, and the way it structures the tissues that it builds, are what make this machine revolutionary.
Atala’s 3D printer can inject cells suspended in gel, and those cells can be anything from mouse muscle to rabbit cartilage to human stem cells filtered from amniotic fluid. The key to the machine’s success, however, is that it combines those cells with another material, a biodegradable plastic called polycaprolactone. Like an itty-bitty scaffold, this plastic keeps the printed tissue around it structurally sound as it is being fabricated and as the growing cells take root. Later on, it degrades away.
“This is very important. This process allows the tissues we print to keep the structural integrity necessary to implant inside the body,” Atala says. “Basically we’re printing a thread of hard [plastic], then a bead of these soft cells intermittently. So: hard, soft, hard, soft.”