It has a nasty disposition, a painful bite and a loud bark. But the orange-spotted, slate-blue Tokay gecko has at least one endearing characteristic: adhesive feet. For years, scientists have been fascinated by the lizard's ability to walk on vertical surfaces, and now researchers from Stanford, UC-Berkeley and Lewis and Clark College -- the self-styled Gecko Team -- are turning up results that just might yield gecko tape or climbing gloves.
In findings published in the June issue of Nature, the team noted that gecko feet get their remarkable adhesion not from sticky secretions or suction cups, but from two million tiny filaments or fine hairs. When a single hair, or setae, comes into contact with a surface -- whether it's metal, plastic or glass, in the air or under water -- an intermolecular force is activated that is also a strong adhesive bond. Tom Kenny, an assistant professor of mechanical engineering, designed a tiny sensor that could measure that adhesive force, and graduate student Yiching Liang, ms '98, figured out how to isolate and attach a single gecko toe hair -- one-tenth the diameter of a human hair -- to a pin that could be pressed into contact with Kenny's device. They estimate that one million toe hairs could hold up to 45 pounds.
Funded in part by a grant from the Office of Naval Research, the Gecko Team is hoping to use its studies to create agile, inexpensive robots that could explore Mars or search through disaster sites for survivors. "The gecko is a possible model for a robot because it does things that we haven't been able to make robots do," Kenny says.
Hollywood's special-effects mavens must be hanging on every word.
