3D printing has expanded into nearly every arena of the medical world of late, from creating 3D-printed organs to developing completely live body parts. Scientists have even developed tiny printed surgical tools that can make surgeries less invasive. Most recently, a team of researchers from the Wallenberg Wood Science Center in Sweden have found a way to create 3D-printed cartilage that may one day heal damaged noses, ears, and knees.

“Three-dimensional bioprinting is a disruptive technology, and is expected to revolutionize tissue engineering and regenerative medicine,” said Paul Gatenholm, lead author of the study, in the press release. “Our team’s interest is in working with plastic surgeons to create cartilage to repair damage from injuries or cancer. We work with the ear and the nose, which are parts of the body that surgeons today have a hard time repairing. But hopefully, they’ll one day be able to fix them with a 3D printer and a bioink made out of a patient’s own cells.”

The research, which will be presented at the 251st National Meeting and Exposition of the American Chemical Society (ACS), describes a special type of printed ink, or “bioink,” that the researchers made out of living human cells. Their goal was to produce bioink that could fill a mold for a nose or ear then keep its shape afterwards. Previously, attempts to create printed bioinks have resulted in the materials losing shape.

The researchers’ new ink was made of polysaccharides from brown algae as well as tiny cellulose fibrils from wood or bacteria. They also mixed in human chondrocytes, cells that build cartilage, which allowed the ink to produce cartilage in a laboratory dish. This meant it could repair broken cartilage in various parts of the body that were damaged — like the knees or nose. The researchers then tested it in mice, implanting the ink into them and watching as the cells continued to produce cartilage.

Their next step involved increasing the number of cells in the mice that could produce cartilage. To do so, the researchers mixed the chondrocytes with human mesenchymal stem cells, which they pulled from bone marrow. These stem cells were able to trigger further production of cartilage from the other cells.

“We have developed a new bioink, CELLINK, for printing living soft tissue with cells,” the researchers wrote in the abstract. “The human chondrocytes have been successfully printed with CELLINK in a complex 3D shape of the human ear, and cells showed good viability after printing and crosslinking.”

In the past, researchers were able to 3D print nose cartilage in the context of reconstructive surgery on a damaged nose. This is the first time, however, that researchers have developed a bioink that can be molded into different body parts — from the ears to the knees — and spur the production and buildup of cartilage. Bioink holds a lot of promise as a feature of 3D printing, but the researchers will need to complete further tests before taking their results to the next level and collaborating with plastic surgeons on clinical applications.