Engineers Create Artificial Skin That 'Feels' Temperature Changes
January 31, 2017 | CaltechEstimated reading time: 2 minutes
A team of engineers and scientists at Caltech and ETH Zurich 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 new material can be as little as 20 micrometers thick, and is both transparent and flexible.
The material could be grafted onto prosthetic limbs to restore temperature sensing in amputees. It could also be applied to first-aid bandages to alert health professionals of a temperature increase—a sign of infection—in wounds.
While fabricating synthetic woods in a petri dish, a team led by Caltech's Chiara Daraio created a material that exhibited an electrical response to temperature changes in the lab. It turned out that the component responsible for the temperature sensitivity was pectin, a long-chain molecule present in plant cell walls.
"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," says Daraio, professor of mechanical engineering and applied physics in the Division of Engineering and Applied Science.
Chiara Daraio, professor of mechanical engineering and applied physics in the Division of Engineering and Applied Science, explains how the new temperature-sensitive artificial skin works.
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 micrometers 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. As temperature increases, these bonds break down and the double strands "unzip," releasing the positively charged calcium ions.
Either the increased concentration of free calcium ions or their increased mobility (likely both, the researchers speculate) results in a decrease in the electrical resistance throughout the material, which can be detected with a multimeter connected to electrodes embedded in the film.
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 fibers expand as temperature increases. This dilation allows calcium ions to flow, triggering electrical impulses.
Existing electronic skins can sense temperature changes of less than a tenth of a degree Celsius across a 5-degree temperature range. The new skin can sense changes that are an order of magnitude smaller and have a responsivity that is two orders of magnitude larger than those of other electronic skins over a 45-degree temperature range.
So far, the skin is capable of detecting these tiny changes across a range of temperatures roughly between 5 to 50 degrees Celsius (about 41 to 158 degrees Fahrenheit), which is useful for robotics and biomedical applications. Next, Daraio's team would like to boost that up to 90 degrees Celsius (194 degrees Fahrenheit). This would make pectin sensors useful for industrial applications, such as thermal sensors in consumer electronics or robotic skins to augment human-robot interactions. To do so, they will need to change the fabrication process they now use to create the material, as that process leads to the presence of water—which tends to bubble or evaporate at high temperatures.
At ETH, Daraio collaborated with postdoctoral researcher Raffaele Di Giacomo; graduate students Luca Bonanomi and Vincenzo Costanza; and guest professor Bruno Maresca, from the University of Salerno, Italy. Their paper is titled "Biomimetic temperature-sensing layer for artificial skins." This research was funded by the Swiss National Science Foundation.
Suggested Items
Boeing Opens Research & Technology Center in Japan
04/23/2024 | BoeingBoeing today opened a Boeing Research & Technology (BR&T) Center in Japan that will focus on innovation to enable the commercial aviation industry meet its goal of net zero carbon emissions by 2050.
Ansys Joins BAE Systems’ Mission Advantage Program to Advance Digital Engineering Across US Department of Defense
04/16/2024 | ANSYSAnsys announced it is working with BAE Systems, Inc., to accelerate the adoption of digital engineering and MBSE across the Department of Defense (DoD).
Incap Estonia Teamed Up With Solaride to Fuel Youth Excitement for The World of Engineering
04/11/2024 | IncapIncap Estonia partnered with Solaride to ignite enthusiasm among young people for the world of engineering and sustainable technology. Together, they organised an inspiring day for students from grades 7 through 12 in Saaremaa. Held at Incap’s Kuressaare factory, this event brought together over 130 young minds eager to explore the innovative world of technology and learn more about advanced electronics manufacturing.
Mark Schulman Rocks Zuken Innovation World + integrate24
04/10/2024 | ZukenZuken USA, Inc. is excited to announce that the renowned drummer and motivational speaker, Mark Schulman, will be the keynote speaker at this year's Zuken Innovation World Americas (ZIW) conference, co-located with integrate24. Scheduled for September 17-19, 2024, in the vibrant city of Cleveland, Ohio, the conference aims to bring together the brightest minds in the PCB, Wire Harness, and Digital Engineering fields.
Saab Announces Plans for New Munitions Facility in U.S.
04/03/2024 | SaabSaab announced plans to build a new munitions facility in the U.S., continuing the company’s strong investment and growth domestically.