If you've ever been pulled out to sea by a riptide you know the true power of the oceans. When a tide changes, waves can crash down on the shores with immense power, and if you're destined to live on these shores you'd obviously have to endure a lot. And in a new study published this week in the journal of the Royal Society Interface, researchers from the University of Portsmouth and the Queen Mary University of London are revealing just how much.
In the new study researchers reveal that in order to keep their place on the rocks of most shores, aquatic snails known as limpet species have the strongest known animal teeth on the Earth. Beyond that, their tough teeth are now considered to be the strongest biological structures on the planet Earth.
"Limpets evolved strong teeth as the teeth scrape over rock surfaces every day to feed" lead author of the study, Asa Barber says. "If the teeth broke easily then the limpet would not be able to feed and would die - hence evolution selecting the strongest teeth over many years."
The analyses by the team concluded that the teeth are composites made primarily from mineral fibers known as goethite. The fibers are bound together by chitin, a natural polymer which acts as a form of natural glue. And just as the limpets bind themselves in place with aid of their natural salivary glue, this chitin polymer is strong enough to withstand far more than the crashing waves they encounter.
So, why are they so strong?
"The strength of the tooth is due to the diameters of the fibers being below a particular size, which is about 60 nanometers, or over a thousand times thinner than a human hair" Barber says. Their shape and material composition lend to the overall strength of the teeth, and in spite of their tiny size, the teeth prove to be incredibly resilient.
Much like current research into spider silk, whose tensile strength has biotechnologist seeking for ways to replicate the natural fibers, new studies are eagerly investigating limpet teeth in hopes of replicating their structure to create similar composite materials that would be useful in mining equipment. Biomaterials researcher Peter Fratzl of the Max Planck Institute of Colloids and Interfaces says that limpet teeth may in fact hold promise for drastically improving current engineering materials.
"First, [this study] shows that an intricate microstructure makes limpet teeth incredibly strong for biogenic material, certainly stronger than silk or cellulose" Fratzl says. "Second, the experimental approach, using tiny tensile specimens just a few microns long, is really impressive."
