A Close Look at Hagfish Slime

Hagfish are primitive, eel-like fish that are nearly blind and lack jaws or true vertebrae, but they have the unnerving capability of producing copious amounts of slime when disturbed.

Researchers from the Cambridge Polymer Group in Boston and the University of British Columbia are now taking a close look at Hagfish slime, in an attempt to understand how the slime protects the fish in nature and to help determine if the slime could lead to practical materials for industry or medicine.

Hagfish slime is a concoction of mucus and threadlike fibers, and is produced in concentrated form from a series of pores that line the sides of the fish's body. Upon contact with seawater, the concentrated slime expands rapidly into a sticky gel that can ensnare and sometimes suffocate an attacker.

Unlike the mucous produced by the membranes of humans and other animals, which become more rigid, viscous gels at and below ambient body temperatures, the researchers (Gavin Braithwaite, 617-629-4400, gavin@campoly.com; Douglas Fudge, dfudge@interchange.ubc.ca) found that Hagfish slime is much less elastic, even at high concentrations, than its human counterpart.

In addition, over the ranges of temperatures encountered by the hagfish, the gel strength is relatively temperature independent. The insensitivity to temperature perhaps ensures that slime is an effective defense in a variety of conditions. In addition, artificial materials that mimic Hagfish slime chemistry might make good space-filling gels.

One potential application for such gels, explain the researchers, is as a way to curtail bleeding in an accident victim or during surgery. In addition, studying the slime may help us understand how mucins, the components of mucous, function in our own bodies and elsewhere.

There is currently some debate regarding the relative importance of the fibers and the mucous in the material properties of Hagfish slime. The recent research, which was presented earlier this month at the 75th Annual Society of Rheology meeting in Pittsburgh, focused on characterizing the properties of the mucous after the fibers had been removed from the slime.