Currently being developed by scientists at the University of Pennsylvania, the hydrogel contains a modified form of a gooey substance known as hyaluronic acid, which is produced naturally by the body's connective tissue. In recent years, the acid has also been experimentally used to ward off glaucoma, heal damaged cardiac tissue, and refill herniated spinal discs.

In lab tests, the U Pennsylvania hydrogel was injected into degenerated joint cartilage in mice. Such cartilage covers the interfacing ends of the bones within a joint, and when not damaged, it keeps them from painfully grinding against one another as that joint moves.

It was found that after being injected, the hydrogel intertwined with the structural matrix of the cartilage, thus stabilizing and strengthening it. This finding was backed up by other tests, in which the gel restored the regular activity of cartilage-producing/maintaining chondrocyte cells in living cartilage tissue samples.

Additionally, the sticky hyaluronic acid hydrogel was found to provide a good "roosting" surface for mesenchymal stem cells that were subsequently injected into the injured joint. Those cells proceeded to grow into a new external layer of cartilage, further protecting the recently reinforced original tissue beneath.