Approximately one in two Americans will suffer from some form of osteoarthritis—a condition by which the cartilage around joints begins to disintegrate—yet the origin of the disease remains poorly understood and there is no cure. Patients with severe conditions can require joint replacements, in some cases on multiple occasions. But, help may be on the horizon. Researchers have successfully grown living human cartilage on a laboratory chip using 3D-printing techniques. The ultimate goal is to 3D-print custom cartilage using a patient's own stem cells and, further down the road, provide surgeons with a tool that could be threaded through a catheter to print new cartilage precisely where it is needed.
Creating artificial cartilage requires three main elements: stem cells, biological factors to make the cells grow into cartilage, and a scaffold to give the tissue shape. The 3D printing approach pioneered by a team of researchers under the leadership of Rocky Tuan, PhD, Director of the Center for Cellular and Molecular Engineering at the University of Pittsburgh School of Medicine, achieves this by extruding layers of stem cells in a solution. "We essentially speed up the development process by giving the cells everything they need [to grow ], while creating a scaffold to give the tissue the exact shape and structure we want," says Tuan. He presented the research at the Experimental Biology 2014 meeting on April 27 in San Diego, CA.
Tuan is not the first researcher to use 3D printing to grow human cartilage, but his method reportedly represents a significant step forward because it uses visible light. Other projects have relied on UV light, which can harm living cells.
Replacement cartilage could also be a game changer when it comes to battlefield injuries, according to Tuan, who co-directs the Armed Forces Institute of Regenerative Medicine. "We are on a mission," he says.
Tuan's research has also produced the first "tissue-on-a-chip" replica of the bone-cartilage interface. The chip, which contains 96 blocks of living human tissue and measures 4 mm across and 8 mm deep, could serve as a simulation device to learn more about how osteoarthritis develops and to develop drugs to treat the condition.
Next, the researchers hope to combine 3D printing with a nanofiber spinning technique they have developed to create more-robust scaffolds and artificial cartilage that even more closely resembles natural cartilage.