Nature’s Recyclable Fiber: How Velvet Worms Inspire the Future of Bioplastics

 

  

The majority of synthetic fibers and conventional plastics come from petroleum-based resources. High heat or chemical treatments are necessary for their energy-intensive manufacture, and recycling them frequently produces hazardous byproducts. Many biodegradable plastics still lack strength, durability, or environmental impact despite efforts to develop them. Designing materials that are robust, adaptable, and readily recyclable without sacrificing functionality or safety is the difficult part.

Small, caterpillar-like, velvet worms can be found in damp woodlands all over the southern hemisphere. These extinct invertebrates catch their prey with a special slime. After being expelled, the slime quickly changes into nylon-strength fibers that can be reformed into new fibers when they dissolve in water. Without heat, chemicals, or waste, this reversibility—the ability to change from a liquid to a solid and back again—occurs. Until now, the molecular mechanisms behind this reversible transformation remained unknown. But through advanced protein sequencing and AI-driven protein structure prediction using AlphaFold (2024’s Nobel Prize-winning tool), researchers led by Professor Matthew Harrington have decoded the protein structures responsible.

The team identified a previously unknown set of proteins within the slime, structurally similar to immune cell receptors. These receptor-like proteins likely link larger structural proteins during fibre formation. Interestingly, these protein sequences are conserved across velvet worm species from Australia, Singapore, and Barbados—despite having evolved separately for nearly 400 million years. This evolutionary conservation highlights their crucial role in the fibre-forming mechanism. This biological system exemplifies a highly efficient, low-energy, and fully recyclable material process. In contrast to conventional plastic manufacturing—which depends on heat, petroleum-based inputs, and chemical processing—the velvet worm produces robust fibres through simple mechanical actions such as pulling and stretching, using water as a reversible solvent.

Fig. Velvet worm releasing its slime fibers

As Professor Harrington explains, “Nature has already figured out a way to make materials that are both strong and recyclable.” The key insight lies in the protein-binding mechanism that governs fibre formation. If this mechanism can be replicated and chemically tuned, it could pave the way for next-generation bioplastics with inherent recyclability and minimal environmental impact. However, certain limitations must be addressed. For instance, a material that dissolves in water is not feasible for many applications, such as food or beverage containers. Nevertheless, researchers believe that by modifying the protein interaction chemistry, it may be possible to fine-tune material properties while retaining the system’s core advantage—reversibility without harmful byproducts.

This discovery lays a promising foundation for the development of bioinspired, high-performance materials that align with circular economy principles. The next phase involves experimental validation of the identified protein interactions and exploring their synthetic analogues for industrial applications. Though small and obscure, the velvet worm offers a powerful natural model for designing sustainable materials.

REFERENCES

1. Zhaolong Hu, Alexander Baer, Lars Hering, Ivo de Sena Oliveira, Alexandre Poulhazan, Darren C. Browne, Xue Guo, Quentin Moana Perrin, Radoslaw M. Sobota, Shawn Hoon, Georg Mayer, Srinivasaraghavan Kannan, Chandra S. Verma, Matthew J. Harrington, Ali Miserez. Conserved leucine-rich repeat proteins in the adhesive projectile slime of velvet worms. Proceedings of the National Academy of Sciences, 2025; 122 (12) DOI: 10.1073/pnas.2416282122
2. Image sources : https://www.straitstimes.com/singapore/environment/velvet-worm-proteins-sequenced-at-last-one-step-closer-to-becoming-a-bioplastic
3. https://www.horizons-mag.ch/2023/03/02/deciphering-a-natural-super-glue/