The mantis shrimp, common in Indo-Pacific waters, has a strength which belies its diminutive size. Mantis shrimps are crustaceans of the order Stomatopoda
, and their power lies in club-like ‘arms’ which can strike prey with a force of more than a thousand times their own weight.
For years material scientists have studied crab shells, sea urchins and the like for clues to the strength of their strong, protective exoskeletons, but now a multidisciplinary international study is looking to the mantis shrimp in their biomimetic endeavours.
A team led by Assistant Professor Ali Miserez, of the Nanyang Technological University (NTU) in Singapore, Dr James Weaver and colleagues at Harvard University, and Assistant Professor David Kisailus’s team at the University of California, Riverside (UCR), as well as scientists from Purdue University and Brookhaven National Laboratory in New York have all worked on investigations into the properties and structure of stomatopod armour.
The speed with which the mantis shrimp can strike is equivalent to a 5.56 mm bullet from a rifle, allowing it to destroy the shells of molluscs and other crustaceans and even aquarium glass with a few blows.
Analysis of the shrimp’s club showed three distinct regions weaved together to create a structure stronger than many engineered ceramics. On the outer surface, high concentrations of a mineral similar to that found in human bone take the impact of the 50,000 blows struck during the animal’s lifetime. Inside, organised layers of chitin – a complex derivative of glucose – act as shock absorbers, while more oriented chitin fibres enclose the sides of the club.
The research is set to continue with the intention of replicating this tough substance for a myriad of potential applications. From a medical point of view, a bio-compatible material suitable to replace bone and resistant to everyday wear is an exciting prospect.
"Damaged hip implants are a real problem, and cost billions of dollars to the healthcare systems worldwide," said Miserez, who is part of NTU’s School of Materials Science Engineering (MSE) and School of Biological Sciences (SBS). "They also cause painful surgeries to patients when they need to be replaced."
"The highly damage resistant property of the mantis shrimp could be most useful in medical products such as hip and joint implants, as they sustain impacts hundreds of times daily during walking and daily activities," he added.
Other potential uses being examined are lightweight but highly durable components for aeroplanes and electric cars, while Kisailus and his team at UCR are particularly interested in military applications including body armour.