Clear, biodegradable, biocompatible Shrilk! Part silk, part shrimp shell, this new material has the strength and toughness of aluminum alloy – but at only half the weight.
The cheap material could one day replace plastic in a range of consumer products. It could also be used safely in a variety of medical procedures: to suture wounds or serve as scaffolding for tissue regeneration.
For some bioinspiration, the team led by Donald Ingber from the Wyss Institute for Biologically Inspired Engineering at Harvard University looked to insect cuticle – such as that found in the rigid exoskeleton of a housefly or grasshopper.
So why is insect cuticle amazing?
In nature, it provides protection without adding weight or bulk. It deflects chemicals and physical strains on the insect without damaging the bug’s insides. It provides structure for wings. It’s so light, it doesn’t inhibit flight; it’s so thin, it allows great flexibility. And it even varies its properties: rigid along the wings and elastic along the joints.
Insect cuticle is made of layers of chitin and protein that’s organized like plywood. So the team engineered a thin, clear film with the same composition and structure.
- They named it Shrilk because it’s composed of protein from silk and from chitin, which is commonly extracted from discarded shrimp shells.
- That’s also why it can be produced cheaply.
- It’s also easily molded into various shapes, such as tubes.
- By controlling the water content, they were able to reproduce wide variations in stiffness, from elastic to rigid.
As a potentially cheap, environmentally safe alternative to plastic, Shrilk could be used to make trash bags, packaging, and diapers that degrade quickly. As a strong, biocompatible material, it could be used to suture wounds that bear high loads, such as in hernia repair.
The work was published in Advanced Materials last week.
Via Harvard news release.
Image: replica of an insect wing made from Shrilk / Wyss