A fully degradable bioplastic derived from shrimp shells and silk protein could provide solutions for planet-clogging plastics as well as implantable medical devices
Wyss Institute researchers have developed a fully degradable bioplastic by isolating a material called chitosan found in shrimp shells and forming a laminate with silk fibroin protein that mimics the microarchitecture of natural insect cuticle. The new material, called “Shrilk”, can be used to manufacture objects without the environmental threat posed by conventional synthetic plastics, and then it rapidly biodegrades when placed in compost releasing nitrogen-rich nutrient fertilizer. Because chitosan and fibroin are both used in FDA-approved devices, Shrilk also may be useful for creating implantable foams, films and scaffolds for surgical closure, wound healing, tissue engineering, and regenerative medicine applications.
Today, humans produce 300 million tons of plastic per year and recycle only 3%, leaving the other 97% to break down in oceans and landfills where they harm the food chain and our environment. A large number of bioplastics on the market today are made from cellulose, a plant-based polysaccharide material, finding application in packaging and simple containers for food or drinks. However, engineers have been unable to shape these materials into complex 3D shapes while providing the hardiness that is characteristic of conventional plastics.
The Wyss Institute’s bioplastic is made using chitosan, a form of chitin, which is a tough polysaccharide that is responsible for the hardy shells of shrimp and other crustaceans, armor-like insect cuticles, and flexible butterfly wings.
This technology is available for licensing.