Velvet worm shoots slime that stiffens in mid-air

"The fact that the slime transitions from a liquid to a solid in mid-air is extremely unusual," says Matthew Harrington. "It appears that the forces it experiences when ejected initiate the transition." (Credit: Getty Images)

The projectile slime of the velvet worm could inspire sustainable synthetic materials, say researchers.

In the tropical, temperate forests it calls home, the velvet worm uses a projectile slime to capture its prey. When ejected from the worm, the slime transforms into a gel before solidifying into stiff fibers when exposed to air. This forms an inescapable trap for struggling prey.

“The fact that the slime transitions from a liquid to a solid in mid-air is extremely unusual,” says professor Matthew Harrington, co-director of McGill University’s Institute for Advanced Materials. “It appears that the forces it experiences when ejected initiate the transition.”

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In a new study exploring the molecular structure of velvet worm slime, Harrington’s group and their collaborators have found a chemical modification that has been preserved throughout evolution for nearly 400 million years. They say these findings bring scientists one step closer to developing sustainable synthetic materials inspired by this natural phenomenon.

The fibers produced from the slime exhibit a strength akin to nylon, yet they can dissolve in water and be reconstituted into new fibers from the solution. This solidified slime essentially becomes recyclable, Harrington says, a quality with profound implications for inspiring sustainable materials research.

This unusual chemical modification, known as a phosphonate, is extremely rare in land animals and may hold a clue to the materials properties of the slime. “This modification is clearly important to the slime’s function since it has been conserved across species for so long,” says Harrington.

The next phase of research aims to unravel the evolutionary significance of this unique chemical modification and its role in the velvet worm’s hunting mechanism.

The findings appear in the Journal of the American Chemical Society.

Source: McGill University