Scientists have created the first example of a living human cartilage grown on a laboratory chip, an advance that will help treat patients with osteoarthritis or soldiers with battlefield injuries.
Creating artificial cartilage requires three elements: stem cells, biological factors to make the cells grow into cartilage, and a scaffold to give the tissue its shape.
The 3-D printing approach used by researchers in this study achieves all three by extruding thin layers of stem cells embedded in a solution that retains its shape and provides growth factors.
"We essentially speed up the development process by giving the cells everything they need, while creating a scaffold to give the tissue the exact shape and structure that we want," said Rocky Tuan, director of the Center for Cellular and Molecular Engineering at the University of Pittsburgh School of Medicine, member of the American Association of Anatomists and the study's senior investigator.
The researchers ultimately aim to use their innovative 3-D printing approach to create replacement cartilage for patients with osteoarthritis or soldiers with battlefield injuries.
Osteoarthritis is marked by a gradual disintegration of cartilage, a flexible tissue that provides padding where bones come together in a joint.
Tuan said artificial cartilage built using a patient's own stem cells could offer enormous therapeutic potential.
"Ideally we would like to be able to regenerate this tissue so people can avoid having to get a joint replacement, which is a pretty drastic procedure and is unfortunately something that some patients have to go through multiple times," said Tuan.
In addition to offering relief for people with osteoarthritis, Tuan said replacement cartilage could also be a game-changer for people with debilitating joint injuries, such as soldiers with battlefield injuries.
The ultimate vision is to give doctors a tool they can thread through a catheter to print new cartilage right where it's needed in the patient's body.
Although other researchers have experimented with 3-D printing approaches for cartilage, Tuan's method represents a significant step forward because it uses visible light, while others have required UV light, which can be harmful to living cells.
In another significant step, Tuan has successfully used the 3-D printing method to produce the first "tissue-on-a-chip" replica of the bone-cartilage interface.
Housing 96 blocks of living human tissue 4 millimetres across by 8 millimetres deep, the chip could serve as a test-bed for researchers to learn about how osteoarthritis develops and develop new drugs.
The research was presented at the Experimental Biology 2014 meeting in US.