The Fascination of Technology New Materials Inspired by Snail Mucus

In our “Fascination with Technology” section, we showcase impressive research and development projects for design engineers every week. Today: how snail mucus inspires the development of new materials.

Snails are particularly active after a rain shower. Even on the Max Planck Campus in Potsdam-Golm (Germany), common ribbon snails (Cepaea nemoralis) leave behind their shiny trails of slime. Researchers from the “Biomaterials” department at the Max Planck Institute of Colloids and Interfaces recognized the slime as a promising natural material. This is because the snail does not produce just one type of slime, but can vary it as needed so that it becomes liquid, solid, sticky, or slippery.
For the research team, the snail slime thus became the subject of a materials science analysis: How does the snail manage to produce completely different material properties using the same basic building blocks? The researchers provide the answer in a study that has now been published in the journal *Science*. In it, they demonstrate for the first time in detail the biochemical “recipes” the ribbon snail uses to specifically adapt its slime to different tasks.

Snail mucus may seem unremarkable at first glance, but it is an incredibly versatile substance. The fact that snails can specifically alter the properties of their mucus using the same basic building blocks is what makes them so fascinating to researchers. 

Dr. Franziska Jehle

The Building Blocks of Snail Mucus

To understand how nature produces this diversity of materials, the researchers analyzed five different types of mucus. They examined mucus that enables movement, acts as a strong adhesive on surfaces, protects the animal from dehydration, seals the shell during extended periods of rest, and serves as a defense mechanism.
They found that the snail consistently uses the same components for its various types of mucus, mixing them together in different proportions. The chemical building blocks are proteins—primarily collagen—and calcium.
The researchers were surprised to identify collagen VI as a central component of the mucus. This is because the protein is primarily known for its structural role in human skin, bones, and joints. Together with amorphous calcium carbonate—which the snail stores in its glandular tissue and releases along with the mucus as needed—the proportion of collagen VI plays a crucial role in determining the properties of the various types of mucus. Apparently, the snail uses the total amount of proteins and the proportion of collagen VI to adjust how dense the protein network in the mucus is. This has a direct effect on the mechanical properties: the tighter the protein network, the tougher the mucus. Calcium, in its ionic form, serves either to cross-link the material or, as calcite, to reinforce it.

Natural materials can perform an enormous variety of functions using just a few building blocks. Understanding the principles behind this is of great importance for the development of sustainable materials.

Prof. Peter Fratzl

Learning from Nature

“The findings of this study extend far beyond the biology of the snail,” says Prof. Peter Fratzl, co-author of the study and director at the Max Planck Institute of Colloids and Interfaces. “Natural materials achieve an enormous variety of functions with just a few building blocks. Understanding the principles behind this is of great importance for the development of sustainable materials.”
For example, following the model of snail slime, it might be possible to produce environmentally friendly adhesives, functional coatings, or materials for medical applications.