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The true limpet species Patella vulgata on a rock surface in Wales
The newest contender for the strongest material is found in the sea. Science has discovered recently that teeth belonging to tiny marine creatures called limpets are so incredibly tough they could be used to construct boats.
Limpets are snail-type creatures crawling along the sea bed, carrying their portable, cone-shaped homes with them. Scientists decided to use a process known as atomic force microscopy on a set of limpet teeth to test how the material behaves at a microscopic level, and how strongly it bonds together. The University of Portsmouth study came out with surprising results. Professor Asa Barber says: "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, but now we have discovered that limpet teeth exhibit a strength that is potentially higher."
Barber discovered that this is due to goethite, a mineral found inside the teeth and formed by the animal as it grows. Limpets develop strong teeth to latch onto rocks and scrape off algae, their primary food source. As if by design, "the fibers are just the right size to make up a resilient composite structure."
What the team also discovered is that limpet teeth stay the same strength no matter the size. This is really important, as "generally a big structure has lots of flaws and can break more easily... Limpet teeth break this rule as their strength is the same no matter what the size."
Science couldn't have done anything with the discovery earlier, because techniques for splitting the ultra-thin mineral have only recently been invented. "We had to cut out a smaller volume of material out of the curved tooth structure," which is less than 1mm, Barker explains.
According to Barker, the challenge with bio-inspired science is finding natural structures that could prove useful and innovative, as there are so many to choose from. "Nature is a wonderful source of inspiration for structures that have excellent mechanical properties. 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."