Fascination technology A superglue made from the body's own mucus

In our "Fascination Technology" section, we present impressive projects from research and development to designers every week. Today: An adhesive that combines the waterproof stickiness of mussel plaques with mucus as a germ-repellent natural material.

In the animal kingdom, mussels are masters of underwater adhesion: Sea mussels gather on rocks and the bottoms of ships and can hold onto the ocean waves thanks to an underwater adhesive that they secrete through their foot. These persistent adhesive structures have led scientists in recent years to develop similar bio-inspired, waterproof adhesives.

Every surface of the human body not covered by skin is lined with a protective mucus layer—a slimy network of glycoproteins that acts as a physical barrier against bacteria and other infectious agents. In their new work, the engineers combined sticky, mussel-inspired polymers with mucins, glycoproteins derived from mucus, to form a sticky gel that adheres strongly to surfaces.

An international research team from the Massachusetts Institute of Technology (MIT) in the USA and the Collaborative Research Center "Dynamic Hydrogels at Biological Interfaces" at the Free University of Berlin (Germany) has developed a novel adhesive that combines the waterproof stickiness of mussel plaques with mucus as a germ-repellent natural material. The team's new approach to adhesive production could also be adapted to incorporate other natural materials, such as keratin—a fibrous substance found in feathers and hair with certain chemical properties similar to those of mucus.

Materials derived from or inspired by mucus could be used, for example, as multifunctional biomedical adhesives that also prevent infections. Or applying our approach to keratin could enable the development of sustainable packaging materials.

George Degen, Postdoktorand am MIT Department of Mechanical Engineering

"The applications of our material design approach will depend on the specific precursor materials," says George Degen, postdoctoral fellow at the MIT Department of Mechanical Engineering. "Mucus-derived or mucus-inspired materials could, for example, be used as multifunctional biomedical adhesives that also prevent infections. Or, applying our approach to keratin could enable the development of sustainable packaging materials."

Before coming to MIT, George Degen was a doctoral student at the University of California, Santa Barbara, where he worked in a research group studying the adhesion mechanisms of mussels. "Mussels are able to deposit materials that adhere to wet surfaces within seconds to minutes," says Degen. "These natural materials adhere better than commercial adhesives, especially on wet surfaces and underwater, which has long been a technical challenge."

Combine adhesive properties of mussel plaques with properties of mucus

To adhere to a rock or a ship, mussels secrete a protein-rich liquid. Chemical bonds or cross-links serve as connection points between the proteins, allowing the secreted substance to simultaneously solidify into a gel and adhere to a wet surface.

Coincidentally, similar cross-linking features are found in mucin—a protein that is the main non-aqueous component of mucus. When Degen came to MIT, he worked with McKinley, a professor of mechanical engineering and an expert in material sciences and fluid dynamics, and Katharina Ribbeck, a professor of bioengineering and a leading researcher in mucus studies, to develop a cross-linking adhesive that combines the adhesive properties of mussel plaques with the antibacterial properties of mucus.

It's like a two-component adhesive where you combine two liquids, and the chemistry starts to work by the liquid dissolving while the substance simultaneously sticks to the surface.

George Degen

The MIT researchers teamed up with Rainer Haag and other researchers in Berlin, Germany who specialize in the synthesis of bio-inspired materials. Rainer Haag and Katharina Ribbeck are members of a joint research group developing dynamic hydrogels for biointerfaces. Haag's group has produced mussel-like adhesives and mucus-inspired liquids by creating microscopic, fibrous polymers that resemble natural mucins in structure. "It's like a two-component adhesive where you combine two liquids, and the chemistry starts working as the liquid dissolves while simultaneously sticking to the surface," says George Degen. "Depending on the degree of cross-linking, we can control the rate at which the liquids gel and adhere," explains Rainer Haag. "We can do all this on wet surfaces, at room temperature, and under very mild conditions. That is what's unique."

Alternative to existing medical adhesives

In the researchers' assessment, with a little tuning, the adhesive's bonding ability can be further improved. If successful, the material could be a strong and protective alternative to existing medical adhesives.

Secure and Compliant Authentication in Laboratories

Secure & Contactless User Authentication at GMP/GLP