Did you know that human skin is the largest and heaviest organ in the human body? It consists of more than 1.8 square meters, on average. Now, a team of scientists has designed an innovative and portable technological device that tracks movement, heart rate and respiration without using cables, batteries or circuits. The device adheres to human skin like a plaster.
The main function of the skin is protective; creates a barrier between our inside and the outside world. However, the skin does much more than protect us. Its various layers help, among other things, to control body temperature and water loss, and it contains nerve endings that help us detect pressure, vibration, touch and pain.
To take advantage of these skin signals, a team of scientists from Stanford University in California (USA) led by Zhenan Bao, have designed a device that adheres to the skin like a plaster and measures how it stretches and contracts the skin of a person . The device then sends these readings wirelessly to a receiver attached to clothing.
Based on these readings, the researchers were able to monitor a subject’s breathing and heart rate, as well as their arm and leg movements . The device, dubbed “BodyNET”, is described in the journal Nature Electronics that includes the study.
How BodyNET works
The researchers called their device a “body area sensor network” or “BodyNET,” and they define it as “a collection of networked sensors that can be used to monitor human physiological signals.”
In the work, the researchers describe how they tested BodyNET. They glued the sensors to a participant’s wrist and abdomen to detect their pulse and respiration. By placing the sensors on the participant’s elbows and knees, the researchers knew when the subject had moved, as the patch detected stretching and contraction of the skin in the areas corresponding to the flexed muscles.
BodyNET works by radio frequency identification (RFID), a technology that is also used in key card and keyless access systems. With key cards, an antenna on the card collects RFID energy from the receiver and uses it to generate an access code. The card subsequently sends this access code to the receiver.
For this device, the researchers had to find a way to transmit RFID energy through an antenna that could expand, contract and bend along with the skin. They used metallic ink to create this antenna , but soon realized that the signal was not strong enough to keep up with the constant movements and fluctuations of the antenna and the skin.
Thus, they designed a newer and stronger type of RFID system that would send more stable and accurate signals. This innovative system also uses Bluetooth technology to send the readings from the receiver to a smartphone or any other wireless device.
The researchers hope that healthcare professionals will use the device to monitor people with sleep problems and heart conditions. For the team, the next steps are to discover how this revolutionary band-aid can also detect sweat and temperature.
“We believe that one day it will be possible to create a full-body skin sensor array to collect physiological data without interfering with a person’s normal behavior,” says Zhenan Bao, leader of the work.
Referencia: A wireless body area sensor network based on stretchable passive tags. Simiao Niu, Naoji Matsuhisa, Levent Beker, Jinxing Li, Sihong Wang, Jiechen Wang, Yuanwen Jiang, Xuzhou Yan, Youngjun Yun, William Burnett, Ada SY Poon, Jeffery B .-H. Tok, Xiaodong Chen & Zhenan Bao. Nature Electronicsvolume, 2, pages361–368 (2019) DOI: https://doi.org/10.1038/s41928-019-0286-2
