A study published in the Science Robotics exposes a new material that can function as human skin with an ability to 'feel' temperature. This technology may be applied to artificial limbs, as well as first-aid bandages that can notify health professionals of a temperature increase.
Engineers and scientists at Caltech and ETH Zurich developed the artificial skin while fabricating synthetic woods in a petri dish. They learned that the component responsible for the temperature sensitivity was pectin, a long-chain molecule present in plant cell walls. This led them to create a material that exhibits electrical response to temperature changes.
A flexible film that is exquisitely sensitive to changes in temperature. (c) Youtube
"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," Chiara Daraio, professor of mechanical engineering and applied physics in the Division of Engineering and Applied Science told Caltech
Using pectin and water, they developed a thin film measuring about 20 micrometers, which is equivalent to the diameter of a human hair.
The film senses temperature using a mechanism similar to the pit organs in vipers. Those organs allow the snakes to sense warm prey in the dark by detecting radiated heat.
In pit organs, ion channels in the cell membrane of sensory nerve fibers expand as temperature increases. This dilation allows calcium ions to flow, triggering electrical impulses.
The electronic skins can sense temperature changes of less than a tenth of a degree Celsius across a 5-degree temperature range. It can detect tiny changes across a range of temperatures roughly between 5 to 50 degrees Celsius.
However, the experts plan to boost that up to 90 degrees Celsius. Thus, making pectin sensors useful for industrial applications, such as thermal sensors in consumer electronics or robotic skins to augment human-robot interactions.