Thursday, November 20, 2014

Super Geckos!

What would it be like to walk up a wall or to hang from a ceiling? What if you could go out and buy super-powers at your local Walmart? A group of scientists at Stanford University in California have made it possible for a human being to climb the side of a skyscraper with specially designed hand pads.

People have tried to make climbing pads from suction cups or adhesives. They've failed, often painfully. How did the scientists at Stanford succeed? They decided to study one of nature’s best climbers: the gecko.

Geckos are nature’s most spectacular climbers. They can stick to any surface, but they can also un-stick at will. Their foot pads don’t lose stickiness over time, and a very small area can support a lot of weight. The scientists at Stanford realized that if humans were ever going to imitate superheroes, they’d have to imitate nature’s superhero first.

To learn how geckos stick to walls, biologists studied their feet under electron microscopes. It turns out that a gecko’s stickiness happens on the nano-scale .  The pads on a gecko’s feet are covered with tiny spiked made of beta-keratin, the same material that a bird’s beak is made of. Each spike is only 10 micrometers across. That’s about half the diameter of the finest human hair.  The ends of each spike split into a bundle of even smaller spikes that can only be measured on the nanoscale.

When these smaller spikes come into contact with a surface, they take advantage of the Van der Waal forces that attract molecules to each other. The force on any one nano-spike is miniscule. However, each gecko foot has so many nano-spikes that it can hold a kilogram to the ceiling! That means an entire gecko could support over 16 pounds.

The scientists at Stanford created a material with similar properties to the gecko’s foot.  First, they used it to create small climbing robots. These tiny mechanical geckos could be useful for surveillance, building, or conducting maintenance in harsh environments like space or under the sea.
Then, they scaled their product up and tested it on humans. 

Currently, the program is being funded by the Defense Advanced Research Products Association (DARPA).  That means that, in the short term, these gecko-pads are probably going to be reserved for the military and the space program. But don’t despair – they’ll eventually reach the public, just like silicone potholders and Velcro shoes!

So, what do cool climbing pads have to do with your biology class?  Well, when you have to look through a microscope and draw what you see, you’re doing what these scientists did to figure out how geckos climb. And when you’re learning about proteins and their structures you’re getting some of the basics of materials science. 

Learning about how biological materials work helps us develop artificial materials that share some of the same amazing properties.  So, the next time you’re studying something in biology class, think “How can I turn this into a super-power?”

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