Discovered by Harvard’s Wyss Institute, a biodegradable bioplastic made from shrimp shells opens up great prospects for both the packaging industry and medicine.
Shrilk is a biodegradable bioplastic that mimics the flexibility and resistance of butterfly wings.
Today, only 14% of the 311 million tonnes of plastic waste discarded in the world is recycled. Nowhere near enough - but that could change with ideas like the one Javier G. Fernandez came up with.
With a doctorate in nanostructures, this scientist working at the Wyss Institute for Biologically Inspired Engineering at Harvard is an expert in bioplastics, and in particular biopolymers derived from living matter (plants, animals). Most come from renewable cellulose, but have the disadvantage of not completely breaking down and having limited use for packaging or food containers.
Under the aegis of the Wyss Institute’s director, Donald E. Ingber, Javier G. Fernandez is using shrimp shells - more accurately the chitosan present in the skins. This form of chitin is the second most abundant organic material on earth... after cellulose. It is found in the exoskeletons of insects and butterfly wings for example.
Shrimp and silk
Inspired by biomimicry, Javier G. Fernandez combines the chitosan from the shrimp shells with silk protein and then seals the material with beeswax. Shrilk – a contraction of shrimp and silk - is born.
The process has evolved over the years as a result of a fundamental discovery: the molecular geometry of chitosan is affected by the method used to make it. Clearly, a method of manufacture had to be found that preserved the natural structure in order to retain all its mechanical properties.
The method was developed in 2014 and Shrilk that is flexible, resilient and transparent was produced. Its color can even be changed just by changing the acidity of the chitosan. A very economical and environmentally friendly plastic cup of the future could emerge from a handful of shrimps! This was the reason Javier G. Fernandez received the Young Investigator Award in Materials Science from the Bayer Foundation.
A bioplastic which turns into fertilizer
And this shrimp shell based bioplastic has another major advantage: it breaks down in just three weeks, releasing nutrients for plants and the soil. In short, the biopolymer chitosan is a natural fertilizer! It has enormous potential for the large global shrimp producers in Honduras, India and Vietnam.
Other tests on Shrilk have demonstrated that it can be molded or injected in exactly the same way as plastic made from petrochemicals. Its natural constitution makes it a material of the future not only for the packaging industry, but also for the medical sector - because it is biocompatible with the human body. Sutures, tissue regeneration, the list looks promising. And for those allergic to shellfish, no worries, it’s not allergenic!
It is now just a question of moving this promising material from the laboratory to the factory. It has already been described as "one of the five materials that could change the world" by the British newspaper The Guardian.
Main picture: Getty Images