Researchers in Switzerland have developed a mechanism that could make ATMs throw acid during a theft.

The research team at ETH Zurich University was inspired by the bombardier beetle to make the chemical cocktail that can be used to prevent thefts at ATMs.

The beetle releases the caustic spray when threatened. Researchers say that copying nature is sometimes the best way to solve problems.

"When you see how elegantly nature solves problems, you realise how deadlocked the world of technology often is," says Wendelin Jan Stark, a professor from the ETH Department of Chemistry and Applied Biosciences.

The beetle has separate chambers to store hydroquinone and hydrogen peroxide. During an attack, the creature lets the two chemicals into a third chamber, where they mix and release a spray of chemical cocktail.

The new device has plastic films with a honeycomb structure. The spaces in the plastic are filled with one of the two chemicals; hydrogen peroxide or manganese dioxide. The plastic films are stacked on top of each other like a sandwich and are separated by a clear lacquer. The interlayer breaks during an impact and lets the chemicals mix. The mixing results in the release of heat, oxygen and water vapor.

The technology can be used in other places where valuables need to be protected. "This could be used anywhere you find things that shouldn't be touched," said Stark in a news release.

Laboratory experiments showed that the reaction releases more foam than a spray. Infrared images showed that the temperature of the foam reaches 80 degrees Celsius, a news release from the University said.

The technology could also be used to render the banknotes useless during a theft. To protect the cash boxes, researchers make plastic films with manganese dioxide. They then add a dye along with DNA nanoparticles. When the cash box is damaged, the plastic film releases foam and DNA nanoparticles. The dye can be used to trace the notes.

The study is published in the Journal of Materials Chemistry A.