Leggo My Gecko

Question – what do your toothbrush and a gecko have in common?
 
Multiple Choice:
1. They both come in green.
2. They both fit in the palm of your hand.
3. They both get into every nook and cranny.

Correct answer – all of the above.
 
So?
 
While you might choose to ignore choices 1 and 2 and buy an oversized toothbrush that comes in pink, you can understand why choice #3 is important for your toothbrush. Each individual bristle makes contact with your teeth so that it can clean all of the surfaces, including below the gum line and in between. That’s one of the main reasons why we use a toothbrush and not a squeegee. (Other reasons are beyond the scope of this article).
 
But what’s so special about a gecko getting into those hard to reach places like your ceiling or under your table?
 
Two answers. The first is that obviously it has to have a good contact with the wall if it expects to be able to climb straight up.
 
But rodents, insects and, yes, even Spiderman can do that. Why is a gecko different?
 
Rodents and insects are able to climb because they have sharp claws that dig into the crevices of a wall that lets them grab and hold on. Geckos have super-serrated hands and legs and hold on with millions of microscopic hairs that divide into billions of split ends. Each hair is so small that when a gecko makes contact, almost 100% of its foot surface actually “touches” the wall. These minute split ends practically combine with the wall through the molecular force called the “Van der Waals” force. It doesn’t stick and it doesn’t dig in – it actually bonds. And then, almost magically, the gecko reverses the pull on his feet and just lets go.

 
Now I know what you’re thinking. “Leapin’ lizards! If I had a toothbrush with all those fine hairs, I’d never get cavities. It would clean every microscopic square inch of my teeth”.
 
Not quite. You see, once it touched your tooth, one false move and, forget about - goodbye bacteria, it’s goodbye tooth!
 
Which brings us to answer #2. By replicating the unique structure of a gecko’s foot pads, scientists are developing vice-like adhesives that take hold merely by touching a surface. And when moved in the opposite direction, simply slip off with no trace of adhesion.
 
Geckos make it look easy.
 
And you thought they only sold car insurance!