South Korea based Amorepacific, a South Korean beauty and cosmetics conglomerate, in collaboration with Professor Kim Jeehwan at MIT, has developed the world’s first chip-less wireless wearable electronic skin (e-skin) that is sweatproof and can continuously monitor skin changes over long periods of time.

Figure 1: First ever chip free wireless sensors e skin.

Figure 1 shows thatthe key outcome is the development of a conformable e-skin in the form of a breathable patch which is enabled by epitaxial freestanding compound semiconductors. The patches are patterned with artificial human sweat ducts to ensure that sweat permeates through to prevent skin irritation and keep the patch from falling off. [1]

The team produced pure, single-crystalline samples of gallium nitride, which they paired with a conducting layer of gold to boost any incoming or outgoing electrical signal. They showed that the device was sensitive enough to vibrate in response to a person's heartbeat, as well as the salt in their sweat, and that the material's vibrations generated an electrical signal that could be read by a nearby receiver.

In this way, the device was able to wirelessly transmit sensing information, without the need for a chip or battery.The engineers used the same technique to peel away ultrathin single-crystalline films of gallium nitride, which in its pure, defect-free form is a highly sensitive piezoelectric material. [2]

To test their idea, the researchers produced a thin film of pure, high-quality gallium nitride and paired it with a layer of gold to boost the electrical signal. They deposited the gold in the pattern of repeating dumbbells — a lattice-like configuration that imparted some flexibility to the normally rigid metal. The gallium nitride and gold, which they consider to be a sample of electronic skin, measures just 250 nanometers thick — about 100 times thinner than the width of a human hair.

The team also paired the device with a thin ion-sensing membrane — a material that selectively attracts a target ion, and in this case, sodium. With this enhancement, the device could sense and wireless transmit changing sodium levels as a volunteer held onto a heat pad and began to sweat.

The researchers see their results as a first step toward chip-free wireless sensors, and they envision that the current device could be paired with other selective membranes to monitor other vital biomarkers. [3]

References:

1. https://intlbm.com/2022/08/19/amorepacific-develops-chip-less-wireless-electronic-skin/
2. https://techxplore.com/news/2022-08-fabricate-chip-free-wireless-electronic-skin.html
3. https://bioengineer.org/engineers-fabricate-a-chip-free-wireless-electronic-skin/

Cite this article:

Sri Vasagi K (2022), MIT Engineers Developed First Ever Chip Free Wireless Sensors E-Skin, AnaTechMaz, pp.100