The Slime of the Hagfish

Scientists have long been intrigued by a gelatinous slime, or hydrogel, produced by the hagfish. Why the interest? Hagfish hydrogel has been described as one of the “softest elastic biomaterials known.”

Consider: The hagfish is an eellike creature that lives on the seabed. When a predator attempts to eat it, the hagfish ejects a gel from special glands. This secretion contains mucus-forming proteins and thousands of long threads of other proteins. Together, these proteins turn the water around the hagfish into a viscous slime. This slime clogs the gills of would-be predators, prompting them to disgorge the hagfish and flee.

Hagfish hydrogel has remarkable properties. Each of its protein threads is one hundredth the width of a human hair and is up to ten times stronger than nylon. When released into seawater, the mixture of mucus and threads forms a structure similar to a delicate three-dimensional sieve. This structure can retain water 26,000 times its own weight. In fact, the slime is almost 100 percent water!

Scientists have been unable to replicate hagfish hydrogel. “This natural system is far too complex,” says one researcher. Yet, scientists intend to reproduce the protein threads genetically, using bacteria. Their aim is to develop a product that is lightweight, tear-resistant, elastic, and biodegradable. Synthetic protein threads could be used to develop sustainable materials for the textile industry and the medical field. Indeed, the potential applications seem endless.

What do you think? Did the highly complex structure of hagfish hydrogel evolve? Or was it designed?