In an important step towards creating a practical underwater glue, researchers have designed a molecule that can fuse two surfaces underwater.
Inspired by mussels' ability to cling to surfaces despite the constant pounding of waves and wind at the sea, the scientists studied the combination of proteins mussels secrete in the form of byssus threads that extend from their feet and anchor them to rocks, pilings or any other surface in their vicinity.
"We have successfully mimicked the biological adhesive delivery mechanism in water with an unprecedented level of underwater adhesion," said Kollbe Ahn from University of California, Santa Barbara in the US, who is also the lead author of the study.
An adhesive primer that can overcome the barrier of water to adhere to virtually any mineral or metal oxide surface has a variety of applications, from basic repair of materials regularly exposed to salty water, to biomedical and dental uses.
The researchers developed a material that demonstrates a record high wet adhesion — up to 10 times the effectiveness previously demonstrated in other such materials, according to the study.
Key to this technology is the synthesis of a material that combines the key functional molecular groups of several residues found in the biological adhesion proteins.
In mussel feet, the amino acid L-Dopa (also used in humans as a treatment for Parkinson's disease) contains hydrogen-bonding chemical groups called "catechols".
These are found in especially high quantities at the interface between the plaques at the ends of the byssus threads the mussels secrete, and the often wet and submerged surfaces to which they adhere.
By mimicking the characteristics of mussel foot proteins that are particularly rich in this amino acid, the researchers designed a molecule that can prime and fuse two surfaces underwater.
Their findings appeared in the journal Nature Communications.
