Generally speaking, injured cartilage doesn’t heal well ... if at all. In recent years, however, scientists have successfully regrown cartilage at injury sites, using things like hydrogel, microspheres and collagen-based nano-scaffolding. Now, a team of scientists led by Prof. James Yu of North Carolina's Wake Forest Institute for Regenerative Medicine have developed something else – a 3D printer that creates implantable cartilage.

For some time now, it’s been possible to create items such as artificial arteries using what’s known as a 3D bio-printer. What’s unique about the new device is the technologies and printing materials that it combines.

One of those technologies is electrospinning. In this process, an electrical current is utilized to create fine fibers from a synthetic polymer solution. These fibers are used to create a porous nanostructure which serves as a sort of “nesting ground” for cartilage cells, making it easier for cartilage adjacent to the injury site to grow back into it.

Flexible mats of this electrospun polymer then have a solution of cartilage cells (obtained from a rabbit ear) deposited on them using traditional ink jet printing. A series of these “seeded” mats are layered together, until they form a structure measuring 10 cm (3.9 inches) diagonally by 4 mm thick.

This material is the finished implantable cartilage. Due to its synthetic polymer content, it is said to offer considerably more mechanical stability than some previous efforts, which consisted of tissue made solely from ink jet-printed gel – an important consideration, given that the material would likely be implanted at high-stress areas such as knees.

Pieces of the 3D-printed cartilage were strength-tested with weights, plus they were implanted in mice. After eight weeks, the implanted samples reportedly “appeared to have developed the structures and properties that are typical of elastic cartilage, demonstrating their potential for insertion into a patient.”

A paper on the research was published yesterday in the journal Biofabrication.

View gallery - 2 images