A new material that mimics the exoskeleton of insects has the strength and toughness of aluminum, but weighs half as much. "Shrilk," developed by a research team at Harvard University's Wyss Institute for Biologically Inspired Engineering, is also low-cost, biodegradable, and biocompatible.
Shrilk has possible applications in medicine for wound dressings, and as a possible alternative to packaging that degrades quickly. It was developed by Javier G. Fernandez, PhD, a postdoctoral fellow at the institute, and Donald Ingber, MD, PhD, the institute's founding director and a professor of bioengineering at the Harvard School of Engineering and Applied Sciences.
A biodegradable, biocompatible material that mimics the exoskeleton of insects has the strength and toughness of aluminum, but weighs half as much.
Source: Wyss Institute
The research team studied the mechanical and chemical interactions between the different layers of natural insect cuticle, the material that makes up an insect's exoskeleton. These layers are chitin, which is a polysaccharide polymer, and protein, organized in a laminate-type, plywood-like structure. Interactions between these two materials give the natural cuticle its unique mechanical and chemical properties.
The team then recreated the cuticle's chemistry and laminar design in the lab, engineering a thin, clear film with similar composition and structure. Shrilk is composed of chitosan derived from chitin and a fibroin protein derived from silk. Chitin, one of the most abundant polymers, is readily available in large quantities as a waste product of shrimp. Shrilk can therefore be produced for a very low cost. It can also be easily molded into a variety of complex shapes, such as tubes.
Natural insect cuticle is very tough, but also very lightweight, and thin enough to be flexible. It protects but does not add weight or bulk. It can therefore resist external chemical and physical stresses while also providing structure.
Sorry I didn't get the joke, Rob, but I still think it's a valid question.
To my mind, the big question about so many of these new alternative materials is how sustainably they can be manufactured and whether they can be recycled in one fashion or another: whether that's biodegrading or being turned into fuel via a waste-to-energy process (and how bad or good those may be for the environment). Like you have often said, it's the whole lifecycle that must be considered.
Well, the boric acid was a joke -- and top of mind as I'm fighting a sugar ant infestation.
But to the point, the more I read your articles as well as articles about energy savings attempts in automotive and aerospace, over and over, it's the materials that matter. Plus, many of the newly develop materials are environmentally friendly in their own right.
Rob, that's an interesting chemistry question. Since this material only mimics an exoskeleton and is actually made of shrimp shells and silk, boric acid won't have the same effect on it. But it might also damage it.
And I agree with you, I think that one big method for reducing dependence on fossil fuels may be better materials.
Beth, that's the first thing I thought when I saw the comparison with aluminum--whether this material might have apps in aircraft, either wings or other components, instead of or in addition to composites. I'm wondering the same thing about this material as Chuck mentioned, just exactly how it compares with aluminum in strength and stiffness, as well as shear.
Impressive material. Just have to keep it away from boric acid (that's the insecticide that kills ants by harming the exoskeleton).
I could imagine an unlimited number of uses. From your articles, I'm beginning to think that one strategy for energy use reduction and sustainability is going to be advances in materials.
This story also puts me in mind of the upcoming Medical Design & Manufacturing conference in Feb. (Link is here.) Not intending this to be a promo for the show, but it's about medical devices and of course miniaturization is the big trend in that area, and anything enabling strong but small packaging will/could be a significant driver of new product development.
Ann, thanks for another interesting article. Beth, you are absolutely right about biomimickry ("biomimetics" is the fancy word for this).
As Ann's article points out, the key to getting the strength and toughness of insect cuticle was reproducing the lamellar structure, with hard (chitosan) and soft (fibroin) layers. Many biological materials are able to achieve amazing properties through the proper arrangement of hard and soft segments. Perhaps even more amazing, these materials are self-assembled at the molecular level!
There is a lot of fascinating work going on in materials engineering departments related to the structure and properties of biological materials. Dr. Marc Meyers and his group at UC-San Diego have done some very interesting work on clam shells, toucan beaks, and armadillo armor, among other materials.
There is also a lot of fasinating work attempting to create new materials based on principles found in nature. Dr. Robert Ritchie of UC-Berkley gave an interesting presentation at last year's Materials Science and Technology conference in Columbus about work he has been doing using ice templates to create polymer-ceramic composites with structures based on mother-of-pearl. These materials are incredibly tough, tougher than many aluminum alloys.
Molecular self-assembly of strong, tough, lightweight, nanostructured materials is something which we, as materials engineers, would love to be able to do. Our bodies, and the natural world around us, do it every day, yet we are only just beginning to learn how it's done.
I would think lots of applications in aerospace because afterall aircraft wings are in really no more than a biomimickry interpretation of bird's wings. Maybe this material, once it evolves and is commercialized, can give composites a run for the money!
Lightweight airplane wings are one of the possibilities I had in mind, too when I first saw this, and not only because the researchers started with the proposition of recreating an insect wing's material. It was the comparison with aluminum that caught my eye, since that comparison is so often made by composite manufacturers, especially in aerospace apps.
With LEDs dropping in price virtually every year, automakers have begun employing them, not only on luxury vehicles, but on entry-level models, as well.
The 3D printing revolution seems to have a knack for quickly moving technology ahead by way of collaborative effort and even a little friendly competition -- all of course in the name of scientific advancement.
Advantech has launched a new series of motion-control I/O modules to meet the increased demands that come with more distributed industrial systems that require control of a growing number of axes and devices.
Using almost 200 light-emitting diodes in the front and back of the new 2014 CTS, Cadillac designers are showing how LEDs can change the character of a vehicle.
From Dell / Intel® New Paradigms in Design Work Scott Hamilton, vertical market strategist for Dell Precision workstations, 5/2/2013 3
Early in my career, I worked as a draftsman and remember the days of drawing on vellum with numbered pencils and Mylar with plastic lead. This was a fun experience in the sense that I ...
I've been using workstations for more than 10 years and love finding ways to get more performance from my system. With demanding professional applications that require more power each ...
A lasting memory from my first job as an engineer in an auto assembly plant is standing on hard concrete at six in the morning, vending-machine coffee clutched in hand, listening to ...
A quick look into the merger of two powerhouse 3D printing OEMs and the new leader in rapid prototyping solutions, Stratasys. The industrial revolution is now led by 3D printing and engineers are given the opportunity to fully maximize their design capabilities, reduce their time-to-market and functionally test prototypes cheaper, faster and easier. Bruce Bradshaw, Director of Marketing in North America, will explore the large product offering and variety of materials that will help CAD designers articulate their product design with actual, physical prototypes. This broadcast will dive deep into technical information including application specific stories from real world customers and their experiences with 3D printing. 3D Printing is
To save this item to your list of favorite Design News content so you can find it later in your Profile page, click the "Save It" button next to the item.
If you found this interesting or useful, please use the links to the services below to share it with other readers. You will need a free account with each service to share an item via that service.
Tweet This
4 
