Faux cartilage could take joint pain away

Athletes who suffer from torn-cartilage injuries may soon be in luck. Mimicking the strength and suppleness of natural cartilage is tricky, but Duke researchers have developed a synthetic version that comes pretty close to the real thing.

Articular cartilage, the tissue between bones and joints, enables us to bend body parts like elbows, hips, and knees. But overuse or injury can lead to wear-and-tear on cartilage, making movement painful and difficult.

The new artificial cartilage is the result of collaboration between two Duke engineers: Farshid Guilak, professor of orthopedic surgery and biomedical engineering, and Xuanhe Zhao, assistant professor of mechanical engineering and materials science and founder of Duke’s Soft Active Materials Laboratory.

In 2007, Guilak and his team designed a three-dimensional fabric “scaffold” into which stem cells could be injected and grown into articular cartilage tissue. Made of tiny woven fibers, the scaffold is about a millimeter thick, with each of its seven layers about as thick as a human hair.

Next Guilak went hunting for the proper material to fill the empty spaces between the scaffold’s layers. Some materials he tried were too fragile, while others were too firm. Meanwhile, Zhao proposed a theory for durable hydrogels (water-based polymer gels). In 2012, he collaborated with a team from Harvard University to create a strong yet pliable interpenetrating-network hydrogel.

Guilak and Zhao recently joined forces to insert hydrogel into the woven scaffolds, the results of which appeared in the December 2013 issue of the journal Advanced Functional Materials. While it’s not quite as good as natural cartilage, it is “a very promising candidate for artificial cartilage in the future,” according to Zhao. So far, the design has outperformed other artificial replacements.