Researchers Successfully Implant 3D-Bioprinted Human Cartilage in Mice

Swedish researchers used a bioink composed of human cells to 3D print and implant cartilage into mice — with results that could lead to advances in reconstructive surgery.

A team of researchers in Sweden successfully implanted 3D-bioprinted human cartilage into mice, a development that could eventually yield medical solutions like complete, bespoke replacements for human noses or ears - skin included.

The researchers printed a hydrogel of nanocellulose mixed with human-derived cartilage cells, then surgically implanted the structures into mice. Once implanted, new blood vessels formed within the printed cartilage.

"This is the first time anyone has printed human-derived cartilage cells, implanted them in an animal model and induced them to grow," said Dr. Paul Gatenholm, professor of biopolymer technology at Chalmers University of Technology in Gothenburg, Sweden.

Gatenholm stressed the goal of the research is to eventually develop new solutions for real-life medical applications, including reconstructive surgery.

"This is not a party trick," he said. "We're looking for new technology to repair the body."

Damaged cartilage has a limited ability to heal itself. Existing options for replacing human ears or noses lost due to accidents or other trauma are extremely limited, Gatenholm said.

"Normally, cartilage tissue is taken from the patient's rib, and this surgery is painful and difficult," he said.

Eventually, 3D printed cartilage structures for noses or ears may be combined with 3D-printed human skin to form the basis of completely artificial replacement body parts, Gatenholm said.

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Gatenholm said he and his colleagues are already working on solutions for 3D printing human skin. In January, another group of scientists in Spain presented a prototype for a 3D printer that can create functional human skin.

But one problem with creating 3D-printed noses or ears for real human patients is that the new appendages would take a significant amount of time to harden, Gatenholm said.

"The cartilage takes about a month before it grows," Gatenholm said. "So if you put on a new ear, and then you slept on it, it would be deformed."

For now, one possible solution might be to encase the replacement appendage in supportive external bandages until it has time to harden. Advanced techniques in 3D printing may eventually produce appendages with structures that harden faster.

Gatenholm and his team, which hailed from both the Chalmers University of Technology and Sahlgrenska Academy, used a 3D bioprinter manufactured by the Gothenburg-based startup Cellink. Their study was published in the journal Plastic and Reconstructive Surgery Global Open.

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