Patrick P. Mercier, Joseph Wang, and colleagues, University of California, San Diego, La Jolla, USA, have developed a noninvasive alcohol test using a skin-worn biosensing system. The sensor uses the fact that the alcohol that passes into our blood is also found in our sweat.

In the first step, the patch makes the skin perspire by bringing the sweat-inducing drug pilocarpine into the skin using a slight current stimulus. When the skin begins to sweat, an alcohol-oxidase enzyme in the patch reacts with very small quantities of alcohol. This electrochemical reaction generates a signal in the measurement electrodes, which can be transmitted wirelessly to a phone. The sensor registers even very small amounts of alcohol reliably and responds linearly to an increasing dose.

The patch was more accurate and reliable than the classic breath test, which measures alcohol in exhaled air. Because all components are inexpensive and easy to produce, it is well suited for mass production. Depending on the purpose, it can be produced as a disposable patch or a reusable system. According to the researchers, the alcohol test patch could, for example, be built into vehicles to measure the driver’s blood alcohol concentration.

• Noninvasive Alcohol Monitoring Using a Wearable Tattoo-Based Iontophoretic-Biosensing System,
  Jayoung Kim, Itthipon Jeerapan, Somayeh Imani, Thomas N. Cho, Amay Bandodkar, Stefano Cinti, Patrick P. Mercier, Joseph Wang,
  ACS Sens. 2016, 1, 1011–1019.
  DOI: 10.1021/acssensors.6b00356