A discovery about the slime projected by velvet worms could revolutionize the design of sustainable materials, according to a study conducted by a research team from McGill University.
The team found that a natural protein structure, preserved by animal species from Australia, Singapore, and Barbados over nearly 400 million years of evolution, allows their slime to transition from liquid to fibrous states and back. This discovery could pave the way for the next generation of recyclable bioplastics.
"Nature has already found a way to make materials that are both strong and recyclable," said Matthew Harrington, a chemistry professor and Canada Research Chair in Green Chemistry, who led the study. "Decoding the molecular structure of velvet worm slime brings us closer to the moment when we can replicate this mechanism with the materials we commonly use."
The velvet worm is a creature from the humid forests of the Southern Hemisphere that resembles a caterpillar. To capture prey, it ejects slime that rapidly forms fibers as strong as nylon. These fibers are water-soluble and can later reassemble. Until this study, the molecular mechanism explaining this reversibility remained a mystery.
Using protein sequencing and AI-based structure prediction (the AlphaFold tool, whose design earned a Nobel Prize in 2024), Professor Harrington's team discovered previously unknown proteins in the slime that function somewhat like immune system cell receptors. To form fibers, these receptor proteins bind large structural proteins together. By comparing two subgroups of velvet worms that diverged nearly 380 million years ago, the research team demonstrated the evolutionary importance and functional relevance of these proteins.
A model for recyclable materials
Synthetic fibers and plastics are typically made from petroleum-based precursors. Their production and recycling require energy-intensive processes and often involve heat or chemical treatments. In contrast, the velvet worm uses only simple mechanical forces—pulling and stretching—to produce strong, durable fibers from renewable biological precursors. These fibers can then be dissolved and reused without generating harmful byproducts.
"A plastic bottle that dissolves in water wouldn't be very useful, but we can solve this by modifying the chemical properties of this binding mechanism," said Matthew Harrington.
The study is a collaboration between researchers from McGill University and Nanyang Technological University in Singapore. The team will now conduct experiments to study binding interactions and attempt to determine whether the principle can be applied to engineered materials.