New, self-healing sticky gel that sticks underwater too

WASHINGTON - Scientists are on their way to creating a new type of self-healing sticky gel that could be used as an adhesive or coating for underwater machinery or in biomedical settings as a surgical adhesive or bonding agent for implants.

The idea was inspired from the hair-thin holdfast fibers that mussels secrete to stick against rocks in lakes, rivers and oceans.

“Everything amazingly just self-assembles underwater in a matter of minutes, which is a process that’s still not understood that well,” said Niels Holten-Andersen, a postdoctoral scholar with chemistry professor Ka Yee Lee at the University of Chicago.

“The mussels that live right on the coast where the waves really come crashing in have had to adapt to that environment and build their materials accordingly,” he said.

“These metal bonds are stable, yet if they break, they automatically self-heal without adding any extra energy to the system,” Holten-Andersen said.

A key ingredient of the material is a polymer, which consists of long chains of molecules, synthesized by co-author Phillip Messersmith of Northwestern University.

When mixed with metal salts at low pH, the polymer appears as a green solution.

“Instead of it being this green solution, it turned into this red, self-healing sticky gel that you can play with, kind of like Silly Putty,” he said.

“You can tune the stiffness, the strength of the material, by now having two knobs. The question is, what other knobs are out there?” said Yee Lee, a professor in chemistry at Uchicago.

“A lot of our traditional materials are hard to get rid of once we’re done with them, whereas nature’s materials are obviously made in a way that’s environmentally friendly,” Holten-Andersen said.

The study appears in Proceedings of the National Academy of Sciences Early Edition. (ANI)