Limpet teeth overtake spider silk as ‘strongest biological material’

Scientists in Britain have discovered the strongest biological material known to man, a limpet tooth. Spider silk used to claim the number one slot for strength but the limpet has now claimed poll position.

You are excused for not knowing limpets even have teeth, used to cling to stones on the shoreline and to scrape off algae when the tide is in. The teeth only measure about a millimetres long.

But in studying these teeth researchers from the University of Portsmouth have uncovered a natural substance that could be imitated to produce a strong, light-weight material used in racing cars, boat hulls and plane fuselages.

“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,” said Prof Asa Barber from the university’s school of engineering.

Limpets are shelled creatures that cling with surprising tenacity to rocks and stone surfaces in intertidal areas.

Prof Barber and his team used advanced atomic force microscopy to probe the teeth which are thinner than a human hair and discovered they were extremely tough, made up of fibres of a hard mineral called goethite.

"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," the professor said. Details of the work are published today (wed) in the Royal Society journal Interface.

The new material may be particularly useful because it does not lose strength with increasing size, he said. “Generally a big 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.”

Nature is an ideal source of inspiration for structures that have good mechanical properties, says Prof Barber. Engineers were always on the lookout for “bioinspiration” from nature that might produce a useful material.