If you’re like most people, you probably don’t think much about hydrogels. Even when you encounter them  those Jell-O cubes in the school cafeteria, say, or the Sea Foam Salad you had at Grandma’s  you probably don’t give them a second thought.

But some scientists think about hydrogels a lot, and these materials made up of cross-linking compounds and water have come a long way in recent years. One goal is to develop gels that are stronger and self-healing, with potential applications in tissue replacement and other medical fields.

An advance toward that goal is reported in the journal Nature. Scientists in Japan have created such a gel, primarily of water and clay.

The key for Takuzo Aida of the University of Tokyo; Justin L. Mynar, who is now at the University of California, Berkeley; and colleagues was the development of a binder, a long molecule with extensive “fingers” at the ends, that links the clay particles into a network, trapping the water. The bonds that form the network are relatively weak, which is what makes the material self-healing.