Wearable sensor could be painless solution to blood tests

Researchers from the University of Glasgow have developed a wearable sensor that could help people with chronic conditions avoid the discomfort of pin-prick blood tests.

By measuring the chemical composition of peoples’ sweat, the researchers believe clinicians could diagnose and monitor chronic conditions such as diabetes, kidney disease and some types of cancer, without the need for invasive blood tests.

Much like blood, sweat contains chemicals generated in the human body, including glucose and urea. Current non-invasive wearables are made from rigid materials, making it difficult to ensure constant contact with the skin. More so, wireless systems which use Bluetooth are often bulky and constantly require recharging.

Now, research published in the journal Biosensors and Bioelectronics, details how a team of scientists from the University of Glasgow’s School of Engineering have built a stretchable, wireless system which can measure the pH level of users’ sweat.

The team’s system is based around a sensor capable of measuring pH levels and which can stretch to fit the contours of wearers’ bodies. The device is made from a graphite-polyurethane composite and is the size of a single square centimetre. However, the device can stretch up to 53% in length without compromising performance.  The device can also work after being subjected to flexes of 30% up to 500 times, something of which allows it to be comfortably used on human skin without impacting performance.

The device is also able to wirelessly transmit data to the accompanying ‘SenseAble’ app. It does this through a stretchable RFID antenna integrated into the system. The app lets users track their pH levels in real time.

The research was led by professor Ravinder Dahiya, head of the University of Glasgow’s School of Engineering’s Bendable Electronics and Sensing Technologies (BEST) group.

Professor Dahiya said: “Human sweat contains much of the same physiological information that blood does, and its use in diagnostic systems has the significant advantage of not needing to break the skin in order to administer tests.

“Now that we’ve demonstrated that our stretchable system can be used to monitor pH levels, we’ve already begun additional research to expand the capabilities of the sensor and make it a more complete diagnostic system. We’re planning to add sensors capable of measuring glucose, ammonia and urea, for example, and ultimately we’d like to see a system ready for market in the next few years.”