Back to One’s Senses: Novel Artificial Skin for Restoring Temperature Sensory Functions
A self-powered biosensing platform with memory capabilities that mimic humans’ temperature perception
Treatment of acute damage to the skin is currently hindered by the limited skin repair and remedial therapies that don’t provide complete sensory reversal. Now, scientists from Incheon National University have developed a new type of transparent artificial skin capable of sensing temperature changes with a memory effect that mimics human sensation. Their device is self-powered and can generate energy from UV light to drive other electronic devices, paving the way to more practical biosensing platforms.
As the largest “organ” of the human body, the skin is a major interface in our interactions with the world around us. Skin contains specialized chemical, mechanical, and temperature biosensors that are critical for detecting harmful stimuli. Although the skin excels at repairing itself when damaged, acute injuries can permanently eliminate some or all of its sensory capabilities over the affected area, creating a “blind spot.”
Because current skin repair therapies cannot restore such losses of sensitivity, some researchers have turned to artificial skin as a viable alternative. Flexible artificial skin can accommodate bio-compatible electronic devices and sensors to imitate the natural functions of human skin. However, one crippling limitation of such wearable electronics is that they require an external energy source, like batteries.
In a recent study led by Professor Joondong Kim of Incheon National University, Korea, a research team developed an innovative type of artificial skin containing a self-powered temperature sensing platform. Their biosensing device addresses the key limitations of previous approaches and offers realistic temperature sensing capabilities by mimicking the way human skin reacts to extreme stimuli. Their paper was made available online on November 8, 2021, and will be published in Volume 91 of Nano Energy in January of 2022.
The proposed artificial skin was produced using flexible and transparent thin layers of zinc oxide (ZnO), nickel oxide (NiO), and silver nanowires that, together, form a photovoltaic device. In other words, this artificial skin converts ultraviolet light into useful electricity, which can be used to power wearable electronics in a straightforward and sustainable way.
The temperature sensing capabilities of the proposed artificial skin come from the use of ZnO, which generates an electrical current that increases with temperature (pyrocurrent). What’s remarkable is that this sensing platform has inherent memory properties, meaning that the pyrocurrent is more or less amplified depending on previous exposure to extreme temperatures. In a way, this mimics some of the sensory memory mechanisms that human skin has and on which our body relies to keep away from harmful stimuli. “Artificial skin could become an immediate solution for people with damaged skin sensors so that they can once again experience the natural environment around them with ease,” explains Prof. Kim.
These findings will help guide the design of artificial skin and wearable electronics for a variety of applications, as Prof Kim remarks, “Our work paves the way for the combination of biosensing and built-in memory capabilities via a self-powered architecture, which could find uses in artificial thermoreceptor sensors, self-powered e-skin, artificial biomedical sensors, artificial sensing and memory, and thermal memory.” Let us hope more researchers get their skin in the game so that this technology progresses even further!
Authors: Priyanka Bhatnagar (1,2) Joonpyo Hong (1,2) Malkeshkumar Patel (1,2) Joondong Kim (1,2)
Title of original paper: Transparent photovoltaic skin for artificial thermoreceptor and nociceptor memory
Journal: Nano Energy
(1) Photoelectric and Energy Device Application Lab (PEDAL) and Multidisciplinary Core Institute for Future Energies (MCIFE), Incheon National University
(2) Department of Electrical Engineering, Incheon National University
About Incheon National University
Incheon National University (INU) is a comprehensive, student-focused university. It was founded in 1979 and given university status in 1988. One of the largest universities in South Korea, it houses nearly 14,000 students and 500 faculty members. In 2010, INU merged with Incheon City College to expand capacity and open more curricula. With its commitment to academic excellence and an unrelenting devotion to innovative research, INU offers its students real-world internship experiences. INU not only focuses on studying and learning but also strives to provide a supportive environment for students to follow their passion, grow, and, as their slogan says, be INspired.
About the author
Dr. Joondong Kim is a Professor at the Department of Electrical Engineering in Incheon National University, Korea, and the head of the Multidisciplinary Core Institute for Future Energies (MCIFE). He majored in Electrical Engineering and earned his PhD in 2006 from the University at Buffalo, State University of New York, USA. His research is focused on the design of functional materials and neo-conception devices, neuromorphic memories, photosensors, and transparent photovoltaics. He has published about 230 SCI papers and holds 150 patents.