London: British scientists claim to have found that tree frogs possess specially adapted self-cleaning feet, a finding which may have practical applications for the medical industry.

"Tree frog feet may provide a design for self-cleaning sticky surfaces, which could be useful for a wide range of products especially in contaminating environments – medical bandages, tyre performance, and even long lasting adhesives," said lead scientist Niall Crawford of University of Glasgow.

Tree frogs have sticky pads on their toes that they use to cling on in difficult situations, but until now it was unclear how they prevent these pads from picking up dirt.

"Interestingly the same factors that allow tree frogs to cling on also provide a self cleaning service. To make their feet sticky tree frogs secrete mucus, they can then increase their adhesion by moving their feet against the surface to create friction.

"We have now shown that the mucus combined with this movement allows the frogs to clean their feet as they walk," said Crawford.

In their research, the scientists placed the White's tree frogs on a rotatable platform and measured the angles at which the frog lost its grip. When the experiment was repeated with frogs whose feet were contaminated with dust they lost grip initially but if they took a few steps their adhesive forces were recovered, reported a website.

"When the frogs did not move the adhesive forces recovered much more slowly. This shows that just taking a step enables frogs to clean their feet and restore their adhesion ability," Crawford said.

White's tree frogs have tiny hexagonal patterns on their feet, which allow some parts of the pad to remain in contact with the surface and create friction, whilst the channels between allow the mucus to spread throughout the pad.

This mucus at once allows the frog to stick and then, when they move, also carries away any dirt. If this can be translated into a man-made design it may provide a re-useable, effective adhesive, say the scientists.

The findings have been presented at the Society for Experimental Biology Annual Conference in Glasgow.

(Agencies)