Gecko Adhesive Mimic from Carbon Nanotubes
by Tim McGee, Helena, MT, USA on 08.16.05
For the past several years the Gecko has fascinated materials scientist with its ability to scamper up vertical walls, and hold its body weight with a single toe. Research from the University of Akron has shown that we can create a 'mimic' of the gecko foot using carbon nanotubes, opening up new avenues for adhesives can greatly change the way we build, live, and work - just think of the sticky note.
The Researchers include Dr. Ali Dhinojwala, UA associate professor of polymer science; UA polymer graduate student Betul Yurdumakan; and Nachiket Raravikar and professor Pulickel Ajayan from Rensselaer Polytechnic Institute in New York. The results are attributed to funding from the NSF.
“It is well known that insects such as beetles and reptiles such as geckos have evolved and developed this most effective adhesive system in order to survive,” Dhinojwala says. “The biological system in these creatures has perfected not only the mechanism to attach to steep vertical surfaces but also to detach at will.
“We already have strong adhesives that can support large forces, and we have weak adhesives such as sticky notes that can be used many times but are not strong enough to support large forces,” he adds. “It will be a challenge to figure out how to design an adhesive that can provide a strong attachment to support a large force but at the same time have the capability of detaching itself from the surface with ease.”
The evolution of adhesives in animals has led to a variety of solutions. We are just beginning to look around us and find the value that biology has to offer -we just have to know where to look and what to ask. The potential value of biomimics to help the environment is immense. While gecko ‘glue’ may not save the environment single handedly, the effort may provide a way to reduce use of toxic glues and industrial waste. It also open up new possibilities in materials manufacturing, and waits for creative individuals to make it in to something truly amazing ::U. Akron Press Release ::NSF Article
"Can't...do...plaid!!!
I love the fact that gecko's adhere to surfaces at the "molecular level".
http://news.nationalgeographic.com/news/2002/08/0828_020828_gecko.html
Of similar interest is the project in which genetically modified goats are producing spider silk. I'm sure there's plenty of TH readers out there that would abhore such an idea, but I'm personally a fan of it. Spider silk is the holy grail of building materials for it's strength to weight ratio and flexibility. If we could start producing it in a large scale, it would alleviate a lot of negative repercussions on the environment from the steel industry.
I think there is quite a profound difference between the field of biomimicry and genetic modification.
The nanotubes concept has it's background within the paradigm of mimicing nature - where as the spider silk producing goat has it's basis in changing the very building blocks of nature.
Although I agree with Garth that the 'spider silk' concept would produce a very valuable product, I strongly disagree that the ends justify the means.
If anyone is interested in the topic of biomimicry there is a very interesting mp3 interview with Janine Benyus at http://www.massivechange.com/interviews.html
So Huw, are you suggesting that nanotubes are developing towards being on par with the properties of spider silk?
I ask this earnestly, as I've got a basic understanding of the properties for each, but no real detailed knowledge about either.
Hi Garth, I don't believe the nanotubes are moving towards the properties of the spider silk.
The nanotubes are being used to maximise surface area (from what I can grasp of the articles) which then mimics the fines 'hairs' that the gecko has on their feet. Where as the spider silk concept is based on mixing the DNA of two different species.
Rather than mixing the DNA of a goat with a spider to produce a thread that is stronger than steel, the biomimicry angle would be to try and mimic the biological/chemical process that creates the thread - rather than altering the organism that produces the thread.
Another example would be if I want to make an omelet, I don't modify the chicken with a cow to create a 'cheese egg'.
I thought I would throw in my 2 cents here - just as huw suggested it doesn't require genetic engineering to 'mimic' biology. Using genetic engineering to produce materials is in my mind an interesting if slightly misleading idea. BIology (and genetics) is usually much more complicated then we understand -any scientist worth her salt will tell you we don't know how chaning one gene will effect the system of the organism - this is the inherent problem with gene therapy and genetic engineering in particular. In itself I don't think genetic engineering is the best approach, when we can mimic the basic designs and use materials and techniques unavailable to biology. But Biology in general has us beat in terms of engineering technology, so it is an easy out to try and use what biology has made as a direct replacement. Althuogh I havn't seen 'spider web' clothing or anything like that -reinforcing my earlier statement that it is non-trivial to play with genetics.