Development of Breathable Electronic Skin using Nanofiber Substrate

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DGIST’s research team developed the world’s first electronic skin using nanofiber substrates. Unlike electronic skin using conventional plastic and rubber substrates, the research team developed an electronic skin that is permeable to oxygen, perspiration, and other bodily fluids; it is expected to be useful for long-term health monitoring because it does not cause discomfort or inflammation to the body.

DGIST (President Sang-hyuk Son) announced on Wednesday July 19, 2017 that Professor Sungwon Lee’s research team from the Department of Emerging Materials Science has developed a breathable electronic skin using a nanofiber substrate through a joint research with Professor Takao Someya of the University of Tokyo, Japan.

Recently, wearable electronic devices have been developed, and research and related businesses in association with health monitoring devices using electronic skin have emerged around the world. However, most electronic skin-related technologies utilize materials such as plastic or rubber; thus, they can cause skin irritation or interfere with metabolism when attached to skin or biological tissue.

In particular, when they are attached to the skin for a long duration, they are impermeable to oxygen and can cause skin irritation such as itching and eczema or inconvenience caused by the sensation of having a foreign object attached to the skin. This has been considered as a limitation since it makes it difficult to precisely and chronologically analyze and treat the biometric information of users who exercise without constraint.

To overcome these shortcomings, Professor Sungwon Lee’s research team has fabricated a substrate using one-dimensional nanofibers rather than the conventional two-dimensional planar substrate and applied a technique to develop electronic skin devices thereon. As such, they have succeeded in collecting bio-signals such as body temperature and electromyogram (EMG) for the first time in the world.

The research team fabricated nanomesh conductors, nano-sized (300~700 nm) fiber substrates that are made by coating water-soluble high-molecular Polyvinyl Alcohol (PVA) alcohol with gold particles. On top of that, utilizing conventional electronic skin technology, they have developed an electronic skin that has a sensor that can measure touch, temperature pressure, and the like.

The nanofiber-based electronic skin developed by the research team has good elasticity while retaining its electrical properties; thus, it has excellent adhesion even when attached to joints such as fingers. Also, it has a structure that can circulate air and bodily fluids through nano-sized holes uniformly distributed throughout the substrate.

In addition, it is thinner and softer compared to existing electronic skin, and can be attached with water without using any separate adhesive. This way, users can directly attach the skin to the desired part of the body and measure electric signals and body temperature from their body. Clinical trials have also proven that the biocompatibility of this new skin is higher than that of conventional electronic skin materials.

Professor Sungwon Lee from the Department of Emerging Materials Science said, “After attaching the nanofiber-based electronic skin to the skin for one week, I have witnessed neither foreign body sensation nor skin irritation. I will carry out a follow-up study to develop an electronic skin platform suitable for long-term health monitoring in conjunction with a smart device.”