This heat-sensitive artificial skin may help amputees sense temperature again

New York: Researchers say they have developed an artificial skin capable of detecting temperature changes using a mechanism similar to the one used by the organ that allows pit vipers to sense their prey.

The team, which comprised of engineers and scientists at Caltech and ETH Zurich, believe the material could be grafted onto prosthetic limbs to restore temperature sensing in amputees.

While fabricating synthetic woods in a petri dish, the team led by California Institute of Technology's Chiara Daraio created a material that exhibited an electrical response to temperature changes in the laboratory.

The material could also be applied to first-aid bandages to alert health professionals of a temperature increase - a sign of infection - in wounds.

It turned out that the component responsible for the temperature sensitivity was pectin - a long-chain molecule present in plant cell walls – used in cough drops, jams and all sorts of recipes.

"Pectin is widely used in the food industry as a jellifying agent; it's what you use to make jam. So it's easy to obtain and also very cheap," said Daraio.

Intrigued, the team shifted its attention to pectin and ultimately created a thin, transparent flexible film of pectin and water, which can be as little as 20 micrometres thick (equivalent to the diameter of a human hair).

Pectin molecules in the film have a weakly bonded double-strand structure that contains calcium ions.

Researchers say that the film senses temperature using a mechanism similar - but not identical - to the pit organs in vipers, which allow the snakes to sense warm prey in the dark by detecting radiated heat.

In those organs, ion channels in the cell membrane of sensory nerve fibres expand as temperature increases.

This dilation allows calcium ions to flow, triggering electrical impulses, the researchers explained.

A paper about the new material will be published in Science Robotics on February 1.

(With IANS inputs)