New wearable device that monitors health through sweat

USA: A new wearable, wireless and battery-free device may soon be available to monitor and diagnose health problems just by analyzing sweat on your body, according to a new study published in the journal Science Advances. This wearable chemical sensing platform is much lighter, smaller, and cheaper than the earlier reported wearable sensors with similar performance capabilities.

The device may be able to give an insight into physiological status -- telling you if you are dehydrated, or whether your electrolytes are dangerously out of balance, or even that you have diabetes. It provides real-time information on the wearer’s pH, sweat rate, and levels of chloride, glucose, and lactate — high levels of which could signal cystic fibrosis, diabetes or a lack of oxygen.

“It fits into a broader trend that you’re seeing in medicine, which is personalized, tailored approaches to treatment and delivery of care,” John Rogers, a biomedical engineer at Northwestern University in Illinois and the key architect of the device, told The New York Times.

Researchers have been developing implantable or wearable skin-like electronics for about 15 years and have made many demonstrations of potential clinical applications. These technologies are beginning to mature, but powering them in a user-friendly way remains challenging. Most demonstrations of wearable devices—especially those that collect biochemical data—require bulky batteries or tether the user to an external power source.

A team of researchers from Northwestern University tackled this by developing self-powered sensing elements and a set of compact electronics to transmit data and receive power. These components were then added to a disposable sticker that passively sops up a sweat on a person’s skin and routes it to teardrop-shaped chambers. Some chambers measure sweat volume, while others contain dyes that change color in response to change in pH or chloride levels.

The new device has minuscule holes at its base into which sweat naturally flows. From there, a complex network of valves and microchannels, each roughly the width of a human hair, route the sweat into tiny reservoirs. Each reservoir contains a sensor that reacts with a chemical in the sweat, such as glucose or lactate.

“That’s basically it,” Dr. Rogers said. “There’s nothing that penetrates the skin, and there’s no power supply that’s driving flow.”

The device relies on the same technology that smartphones use to send wireless payments; the phone can both deliver power through this wireless coupling and receives data back. Alternatively, the data could be sent to a reader attached to a treadmill or elsewhere in a fitness room — and, perhaps eventually, to a reader much farther away.

The system is versatile and could be set up to track the same chemical or several, over time, such as the level of lactate in a runner as a marathon progresses. Because the device is waterproof and molded to the body, it also could be used by swimmers to track their performance.

For further reference log on to 10.1126/sciadv.aav3294