Researchers at the University of Pittsburgh’s School of Medicine grew what they claim is the first living human cartilage on a laboratory chip. Artificial cartilage, formed by a patient’s own stem cells, could offer therapeutic benefits, especially to those combating osteoarthritis. Regeneration of material offers a potentially superior alternative to joint replacement.

Osteoarthritis is the gradual disintegration of cartilage—the flexible tissue in joints that acts as a pad between bones. Loss of cartilage causes great pain and loss of mobility in joints like the knees and fingers. One in two Americans are expected to develop some form of it sometime in their lives, and it is one of the leading causes of physical disability in the United States. Unfortunately, the only treatment is joint replacement, as previously mentioned. There is no cure.

The research team, led by Rocky Tuan, Ph. D, director of the Center for Cellular and Molecular Engineering, pinpointed three elements needed to create artificial cartilage: stem cells; biological factors to make the cells grow into cartilage; and a scaffold to give the tissue shape. The 3D printing process meets these goals by extruding thin layers of stem cells embedded in a solution that retains its shape and allows growth. The scaffold speeds up the process by giving the cells exactly the shape and structure they want. Tuan’s new method also uses visible light, not ultraviolet light as was the case with his predecessors—which can be harmful to living cells.

Taking the 3D printing process further, Tuan’s team produced the first “tissue-on-a-chip” replica of the bone cartilage interface. It consists of 96 blocks of living human tissue and measures 4 by 8 mm. The tissue-on-a-chip could provide a new testbed for researchers to develop drugs and learn more about the formation of osteoarthritis. In the future, researchers hope to combine 3D printing with the previously developed “nanofiber spinning technique.” Combining the two may result in a stronger scaffold, making it possible to create a more natural look and feel to artificial cartilage.