We’ve all seen the videos of some poor animal falling into a river and being devoured in a river and being devoured in seconds by a school of piranha. Can any animal or fish resist the slashing razor-sharp teeth of these miniature buzz saws? It turns out, the Arapaima gigas fish is covered with scales that make it piranha-proof. And soon, humans wearing body armor inspired by the Arapaima will be bullet-, blade- and piranha-proof too.
According to his study published recently in the journal Soft Matter, Professor Stephan Rudykh, head of the mechanics for soft materials laboratory at the Technion-Israel Institute of Technology, noticed that the Arapaima gigas is protected by an outer layer of hard scales that interlock. The surprise was underneath them, where he found soft tissue that gives the fish flexibility to move while covered by the impervious scales.
The Arapaima gigas is a large freshwater fish native to the Amazon River where, even though it can reach 15 feet in length, it has to constantly resist attacks from pesky little piranhas. Those scales don’t protect it against humans so Brazil has banned commercial fishing for this tasty fish with its large boneless steaks. It can still be caught by native peoples who salt and dry the meat for long-term storage without refrigeration, making it the “cod of the Amazon.” The tongue has medicinal properties and those protective tough scales can be used as nail files.
Using a 3-D printer and funding from the U.S. Army Research Office, Rudykh and his team from MIT and the Technion-Israel Institute of Technology created lightweight plastic scales and placed them over an elastic material. By adjusting the angles of the scales from 10 to 45 degrees, they were able to make the artificial skin up to 40 times stronger while maintaining its flexibility.
That sounds great but the material is limited by the strength of the plastic. Rudykh hopes to eventually replace it with Kevlar to create lightweight bulletproof uniforms for soldiers and flexible spacesuits for astronauts that can protect against micrometeorites, flying space debris and Klingon blades.
Once again, nature provides a better and more elegant solution than man could develop.