Inspired by Insect Cuticle, Scientists Develop Material That's Tough and Strong

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.

Based on reviews such as Bioplastic Made from Waste Shrimp Shells, the idea seemed to be another example of bio-utilization.  However, the production process allows the properties to be varied by adjusting the moisture during manufacture, an example of how structure/information can be incorporated into existing materials rather than relying on chemistry to develop a brand new material.   According to the source article (reference below):

mechanical testing revealed that the shrilk laminate exhibits an ultimate strength of 119 MPa, which is ten times stronger than that previously described for a chitosan:fibroin blend with similar weight:weight ratios, and it exhibits twice the strength of chitosan, which is its strongest component

The ScienceDaily article described insect cuticle as a composite of chitin and a polymer organized in a structure similar to plywood.  The researchers studied the structure of cuticle and were able to replicate it using chitosan and silk protein.  The resulting clear film is comparable to aluminum alloys in strength and toughness but is half as dense.  At the systems level, shrilk is based on readily available organic materials and manufactured using fairly benign methods.  The material is biocompatible and biodegradable. 

Reference (paid access):

Unexpected Strength and Toughness in Chitosan-Fibroin Laminates Inspired by Insect Cuticle
Javier G. Fernandez, Donald E. Ingber
Advanced Materials, Volume 24, Issue 4, pages 480–484, January 24, 2012
Article first published online: 13 DEC 2011
DOI: 10.1002/adma.201104051

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