Electronic skin patch offers the superior way of monitoring blood alcohol levels

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UC SAN DIEGO

Original press release was issued by the University of California – San Diego

Imagine the morning after a superb Friday’s night out spent in a good company. The wake-up call can be – besides the potential headache – the need to drive to a nearby store or to go pick up a family member from the airport. “Safety comes first”, the motto embedded in your head, pops up as soon as you reach out for the car keys. But are you really safe to sit behind the wheel? You need some proof. Breathalyzer, if you have one, could be handy for its practicality, but isn’t all that reliable. Even a bit of mouthwash could fool it into providing false readouts. Intentional or not, drunk driving is a real problem. After all, the statistics speak for themselves. For example. in the United States, drunk driving accounts for 31% of all traffic-related fatal accidents, among other disturbing facts.

What can be done to prevent people from driving when they shouldn’t be? Researchers from UC San Diego, came with an answer. They have developed a wearable sensor that can accurately measure a person’s blood alcohol level from sweat and transmit the data wirelessly to a laptop, smartphone or other mobile device, all within 15 minutes. In comparison with the existing breathalyzers, this device can be worn on the skin and could be used not only by the drivers, but also by doctors and police officers for continuous, non-invasive and real-time monitoring of blood alcohol content. Additionally, you don’t need to blow into anything.

“What’s innovative about this technology is that the wearer doesn’t need to be exercising or sweating already. The user can put on the patch and within a few minutes get a reading that’s well correlated to his or her blood alcohol concentration (BAC). Such a device hasn’t been available until now,” said Patrick Mercier, an electrical engineering professor at UC San Diego and also the study’s co-director.

According to the researchers, this device provides accurate readouts even after repeated bending and shaking. This showcases that the sensor won’t be affected by the wearer’s movements.

How does it all work? The alcohol sensor consists of 2 parts. First is the “tattoo”, equipped with screen-printed electrodes and a small patch containing pilocarpine, a drug that induces sweat. The second is a flexible electronic circuit board that powers the tattoo and communicates wirelessly with a mobile device. These two parts are joined together with a magnet. The process starts with releasing pilocarpine, thus inducing sweat. Then, the sweat comes into contact with an electrode, generating hydrogen peroxide which is electrochemically detected. That information passes onto the electronic circuit board, which communicates the data to a mobile device.

“The device could be integrated with a car’s alcohol ignition interlocks, or friends could use it to check up on each other before handing over the car keys,” speculates Joseph Wang, a nanoengineering professor at UC San Diego, the study’s director.

The tattoo was already put to the test. 9 volunteers wore it before and after they drank an alcoholic beverage. The readouts reflected the users’ BAC with pinpoint accuracy. As the next step, the team plans to develop a device that could monitor alcohol levels for 24 hours. Even though the research and its practical use could be of great help for teaching careless people to be more reliable, a future, where we could get by without such devices remains, for the time being, just wishful thinking.

Michal Madaras

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