Scientists have discovered a natural material stronger than titanium, Kevlar and even spider silk. In fact, measurements suggest it's the strongest biological material known.


Limpets are marine creatures with conical shells about five centimetres in diameter. (Biopix/Encyclopedia of Life)

The remarkable material was discovered in a place you might not have expected — in the teeth of a tiny, vegetarian sea snail called the limpet, reports a team of scientists led by Asa Barber, a professor in the school of engineering at  the University of Portsmouth in England.

Limpets are marine creatures with conical shells about five centimetres in diameter. Like garden snails, they use a foot to glide along under the shell.

They eat algae on the surface of rocks and have found "an ingenious way of feeding," Barber told CBC's As It Happens.

Instead of moving their bodies as they graze, they extend a tongue-like appendage called a radula. The underside of the radula is covered in rows of teeth used to scrape food toward the limpet's mouth.

Asa Barber

The study was led by Asa Barber, a professor in the school of engineering at the University of Portsmouth in England. (University of Portsmouth)

Barber saw a photo of the limpet's teeth in a textbook, and was struck by their appearance – they were made of tiny fibres of the mineral goethite embedded in a natural plastic material.

"I thought, 'Wow, this is … like the structures we use in aerospace structures, but it's on a much smaller scale," he said.

Such materials tend to be strong and light, so are often used in high-performance cars and aircraft.

That inspired Barber to test their strength using a device called an atomic force microscope. Tests in the lab showed that the teeth were significantly stronger than spider silk.

While most structures become less strong as you make them bigger, due to a larger number of flaws in the structure, that was not the case for the limpet teeth – different sizes were equally strong.

The results were published this week in the journal Interface.

Barber said the key to the material's strength is that the fibres in the teeth are much thinner than those found in man-made composites.

He and his colleagues hope to build a synthetic version of the limpet tooth material to construct items like cars and planes.