It was just last year that we heard how scientists from Stanford University had designed a skin-worn sensor that measures stress via cortisol levels in the sweat. Now, researchers from that same institute have announced a similar sensor that tracks other vital signs.
Known as BodyNet, the new technology was developed by a team led by chemical engineering professor Zhenan Bao. She's no stranger to our pages, having previously brought us innovations such as touch-sensitive robot skin, an implantable blood flow sensor that dissolves when no longer needed, and an e-waste-reducing biodegradable semiconductor.
Her BodyNet sensor is made of a clear, stretchable, non-allergenic elastomer, onto which are screen-printed metallic-ink sensing electronics and a flexible radio-frequency identification (RFID) antenna.
In lab tests, a couple of the devices were adhered onto a test subject's wrist and abdomen, where they accurately measured the person's pulse and rate of respiration by detecting the expansion and contraction of their skin. Additionally, sensors applied to their elbows and knees were able to track the movement of those body parts, by measuring the tightening or relaxation of the skin every time the corresponding muscle flexed.
Data is gathered from the BodyNet sensors using a separate RFID reader, which temporarily powers up the devices using its own radio signal. The wearable sensors themselves contain no batteries or other rigid components.
Currently, one reader has to be affixed to the wearer's clothing over top of each sensor. Down the road, however, it is hoped that a single piece of RFID-reading "smart" clothing – with antennas woven into the fabric – could be used instead. It would periodically transmit the sensor data to a nearby computer, smartphone or tablet via Bluetooth.
Ultimately, once it's capable of measuring additional vitals such as body temperature, the BodyNet technology may find use in the non-disruptive monitoring of patients with sleep disorders or heart conditions, or in the assessment of athletes wishing to optimize their performance.
A paper on the research was recently published in the journal Nature Electronics.
For other recent examples of skin-worn bodily-function sensors, check out what's been created by scientists at the University of Bath, the University of California San Diego, and the Georgia Institute of Technology.
Source: Stanford University