Strongest material in world? Sea snail teeth

Move over spider silk. There is a new material that could just be the strongest known to mankind.

Scientists announced this week that the teeth of limpets - small aquatic snail-like creatures with conical shells - are so strong they could be mimicked to make the next generation of racing cars or airplanes.

"Until now we thought that spider silk was the strongest biological material because of its super-strength and potential applications in everything from bullet-proof vests to computer electronics," said University of Portsmouth professor Asa Barber, who led a study that found limpets' teeth to be five times stronger than average spider silk.

Barber stumbled upon his discovery while paging through a biology book at the library and coming upon images of the limpets which are millions of years old and found along coastlines around the world. Until Barber came along, no scientists had considered studying the strength of limpet teeth.

"When I saw the structure, I said this was very clearly a composite structure," he said. "But when I looked at the size, the fibers they were using were a hundred times thinner than typical carbon fibers we use in engineering. I thought, wow, this was interesting. What are these teeth doing?"

For Barber, it was a reminder that oftentimes discoveries are right in front of your face - or under your shoes.

"Nature is a wonderful source of inspiration for structures that have excellent mechanical properties," he said. "All the things we observe around us, such as trees, the shells of sea creatures and the limpet teeth studied in this work, have evolved to be effective at what they do."

After sending a student to collect the limpets from the English coast, Barber and his team turned to atomic force microscopy to examine the small-scale mechanical behavior of the curved teeth, which are only slightly less than a millimeter in size. The process allows researchers to pull apart materials all the way down to the level of the atom.

Describing their findings in the Royal Society journal Interface, they found that the teeth contain a hard mineral known as goethite, which forms in the limpet as it grows.

The research also discovered that limpet teeth are the same strength no matter what their size, which overcomes a problem with many scaled up materials - they have "lots of flaws and can break more easily than a smaller structure, which has fewer flaws and is stronger."

"Limpets need high strength teeth to rasp over rock surfaces and remove algae for feeding when the tide is in," Barber said of the mollusks which have existed for millions of years and are found primarily on the coasts of England.

"We discovered that the fibers of goethite are just the right size to make up a resilient composite structure," he said. "This discovery means that the fibrous structures found in limpet teeth could be mimicked and used in high-performance engineering applications such as Formula 1 racing cars, the hulls of boats and aircraft structures."

Barber said his team is now looking to commercialize the discovery and even thinking it could be produced using 3D printing. They will be joining a race that includes engineers using spider silk and graphene to come up with a material that is both light and strong and can replace traditional materials like steel.

"It's going to be in transport structure because you save energy if you make a car half as light, reduce the weight by 50 percent," he said. "You are potentially going to reduce energy consumption 50 percent. Society is looking toward that in the future."