Taking design cues from insects and shrimp, materials scientists at Harvard have created a material that’s as strong as aluminum alloy but only half the weight. The substance, dubbed “Shrilk” by its creators, is a material analog for insect cuticle--the material found in the exoskeletons of insects--and is the synthetic equivalent to one of nature’s strongest, lightest, and most interesting materials.
Insect cuticle is nature’s way of providing serious strength and protection without adding weight that would inhibit movement or flight. Moreover, it exhibits a variety of properties, often being rigid through the bulk of the insects body but flexible in the appendages and wings and elastic through joints. It is composed of specific proteins and layers of chitin, a polysaccharide polymer found in biological materials like shrimp shells.That’s exactly where the researchers started. Using chitin derived from discarded shrimp shells, the team was able to mimic the mechanical and chemical interactions that make insect cuticle so remarkable between their chitin and a fibroin protein from silk, which they organized in laminar structure. The result is a thin, clear film that exhibits the same properties as real, natural insect cuticle. It’s cheap, biodegradable, and offers the strength and toughness of a metal alloy at roughly half the weight.
Potential applications include a biodegradable replacement for many plastics, making everything from trash bags to diapers to packaging more eco-friendly without sacrificing strength or integrity. The researchers from Harvard’s Wyss Institute for Biologically Inspired Engineering also envision Shrilk becoming a strong biocompatible material used in medical practice for everything from load bearing wound sutures to scaffolds for regenerative tissue therapies. Meaning that someday soon, human beings may repair their bodies with the stuff of insect exoskeletons.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.