The gecko lizard sticks to the wall with the help of a layer of fatty

published on wednesday 06 july 2022 at 01h22

The gecko lizard appears to defy gravity by “sticking” to the wall, thanks in part to an ultra-thin layer of fat covering the tips of its legs, according to a study published Wednesday.

Scientists have long been intrigued by the almost supernatural ability of this little lizard to adhere, and have sought to unlock its secret.

They have known for several years that the tips of the legs of geckos have millions of setulae, elastic microscopic hairs, arranged in a certain order and ending in the shape of spatulas.

This microstructure makes it possible to marry the shape of the surface on which the gecko moves. This phenomenon is explained by the so-called van der Waals forces.

“We already knew a lot about the mechanical behavior of setulae. Now we have a better understanding of how they work at the molecular level,” said physicist Cherno Jaye of the US National Institute of Standards and Technology (NIST). , co-author of the study published in Biology letters.

NIST researchers found, using an X-ray microscope, that the setulae and their spatulas were covered in a fatty film one nanometer thick, one billionth of a meter.

These lipids, which protect tissues against dehydration, could also play a key role thanks to their hydrophobic nature. By repelling any water molecules, they would provide the spatulas “closer contact with the surface”, said Tobias Weidne, a chemist at the Danish University of Aarhus, and co-author of the study, quoted in a press release from the NIST. The whole “would help the geckos to cling to wet surfaces”, according to him.

The researchers envisage very concrete applications, via biomimetics, to research concerning the capacities of the gecko.

“You can imagine gecko boots not slipping on wet surfaces, or gecko gloves to hold wet tools,” said NIST physicist Dan Fischer. And why not, a “vehicle capable of traversing a wall”, according to him.

Until then, the study concludes that further work is needed to determine exactly the usefulness of this lipid film.


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