A climbing system inspired by geckos has turned spider man fiction into fact by making it possible for a human to scale vertical glass.
In a dramatic experiment, an 11-stone volunteer crawled up a 12ft pane using sticky attachments on his hands and feet.
The demonstration recalled the movie Mission Impossible: Ghost Protocol in which Tom Cruise clings to the outside of the world’s tallest building, the Burj Khalifa in Dubai.
But unlike the sucker-gloves employed by Cruise, the gecko devices are technologically sophisticated and real.
They employ the same natural molecular forces that allow gecko lizards to scurry around on ceilings.
Electrostatic Van der Waals forces cause neighbouring molecules to be attracted to each other. Although very weak, the effect is multiplied by thousands of tiny hairs that cover a gecko’s toes, allowing them to stick firmly to surfaces.
Adopting the same principle, scientists created tiny tiles called “microwedges” to generate Van der Waals forces and produce a dry adhesive even more efficient than the gecko’s.
In the test, the volunteer testing the microwedge attachments simply peeled them on and off the glass.
The US team led by Dr Elliot Hawkes, from Stanford University, wrote in the Journal of the Royal Society Interface: “Using this system, a human of mass 70 kilograms (11 stone) successfully ascended a 3.6-metre vertical glass wall with 140 square centimetres of gecko-inspired dry adhesives in each hand.
“We tested hundreds of individual steps on glass with the 70kg climber and 140 square centimetres of adhesive without failure.
“The synthetic adhesion system creates a nearly uniform load distribution across the whole adhesive area, improving upon the adhesive-bearing structures of a gecko’s toe and enabling a human to climb vertical glass using an area of adhesive no larger than the area of a human hand.”
The research was conducted in collaboration with the US Defence Advanced Research Projects Agency (Darpa), whose “Z-man” programme is investigating biologically-inspired climbing aids for soldiers.
One application of the technology might be to help astronauts get around in weightless conditions, the authors suggest.
“Recent work has .. shown that .. microwedges function in the environment of outer space, so it would be of interest to test this adhesion system in such an environment,” they concluded.