Tag Archives: shrilk

Shrilk—save your insect skeletons, they may come in handy

If you should happen to find a dead beetle or other insect with a hard exoskeleton, take a good look and marvel at strength that doesn’t require bulk or weight. Scientists at the Wyss Institute for Biologically Inspired Engineering at Harvard University have been inspired by those exoskeletons, made of  something called insect cuticle, to create a new material, shrilk. From the Dec. 13, 2011 news item on phosorg.com,

Researchers at the Wyss Institute for Biologically Inspired Engineering at Harvard University have developed a new material that replicates the exceptional strength, toughness, and versatility of one of nature’s more extraordinary substances—insect cuticle. Also low-cost, biodegradable, and biocompatible, the new material, called “Shrilk,” could one day replace plastics in consumer products and be used safely in a variety of medical applications.

Natural insect cuticle, such as that found in the rigid exoskeleton of a housefly or grasshopper, is uniquely suited to the challenge of providing protection without adding weight or bulk. As such, it can deflect external chemical and physical strains without damaging the insect’s internal components, while providing structure for the insect’s muscles and wings. It is so light that it doesn’t inhibit flight and so thin that it allows flexibility. Also remarkable is its ability to vary its properties, from rigid along the insect’s body segments and wings to elastic along its limb joints.

Insect cuticle is a composite material consisting of layers of chitin, a polysaccharide polymer, and protein organized in a laminar, plywood-like structure. Mechanical and chemical interactions between these materials provide the cuticle with its unique mechanical and chemical properties. By studying these complex interactions and recreating this unique chemistry and laminar design in the lab, Fernandez [Javier G. Fernandez] and Ingber [Donald Ingber] were able to engineer a thin, clear film that has the same composition and structure as insect cuticle. The material is called Shrilk because it is composed of fibroin protein from silk and from chitin, which is commonly extracted from discarded shrimp shells. [emphasis mine]

The researchers say that shrilk could be used as an environmentally-safe and biodegradable alternative to plastic, e.g. trash bags, diapers, and packaging. It could also be used to suture wounds.