Limpet teeth are found to be strongest natural material on Earth

Engineers believe they may have found the strongest natural material on Earth – limpet teeth. Research conducted at the University of Portsmouth has revealed that the teeth of these small aquatic creatures are so strong they could be copied to make the cars, planes and boats of the future.

A team of researchers at the University’s School of Engineering discovered that limpet teeth contain Goethite, a hard mineral made up of fibrous structures. Together these fibres create a material that rivals the strength of even the toughest man-made fibres. Limpets rely on their high strength teeth for scraping rock surfaces to collect algae to feed on.

Designing materials based on what we see in nature is known as ‘bioinspiration’. Until now, spider silk was thought to be the strongest biological material, with a variety of potential applications from bulletproof vests to computer electronics.

Professor Asa Barber, who led the research, said: “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.”

Replications of limpet teeth may be used in the future for high performance engineering of Formula 1 cars, boat hulls and aircraft structures.

“Engineers are always interested in making these structures stronger to improve their performance or lighter so they use less material…but with so many biological structures to consider, it can take time to discover which may be useful.”

Barber’s team tested a piece of limpet tooth almost 100 times thinner than the diameter of a human hair. A technique called atomic force microscopy was used to pull apart the material down to the level of the atom and examine its mechanical behaviour.

The research also revealed that limpet teeth are just as strong no matter what their size.

“Generally a bigger structure has lots of flaws and can break more easily than a smaller structure, which has fewer flaws and is stronger. The problem is that most structures have to be fairly big so they’re weaker than we would like. Limpet teeth break this rule as their strength is the same no matter what the size.”

The findings of the study, published in the Royal Society journal Interface, even have the potential to be used for future dental restorations. The next challenge for researchers is to work out how limpet teeth can be replicated in the lab to allow the material to be used in engineering.

DOI: 0.1146/annurev.matsci.28.1.271