In the United States alone, one person dies every 53 minutes in an alcohol-related car accident, according to the Centers for Disease Control and Prevention (CDC). To help people easily and quickly determine when they've had enough, scientists have developed a flexible, wearable patch that can detect blood-alcohol level via a person's sweat. The monitor, reported in the journal ACS Sensors, can send results wirelessly to a smartphone or other device.
Currently, ignition interlock devices are being marketed as a way to prevent drunk drivers from starting a car engine. But these are based on breath analysis, which can be affected by a number of factors, including humidity, temperature and whether someone has used mouthwash.
Recent research has demonstrated that sweat can be a more reliable real-time indicator of blood alcohol content. At least two transdermal sensors have been developed to measure alcohol levels in sweat, but users have to wait up to 2 hours for results. Joseph Wang, Patrick Mercier and colleagues at the University of California, San Diego, set out to make a more practical version.
With temporary-tattoo paper, the researchers developed a patch that tests blood alcohol content non-invasively in three rapid steps. It induces sweat by delivering a small amount of the drug pilocarpine across the skin. An enzymatic reaction leads to the electrochemical detection of the alcohol content. And a flexible electronic circuit board transmits the data via a Bluetooth connection to a mobile device or laptop.
The steps take less than 8 minutes from start to finish. In addition to connecting to vehicles' ignition interlock systems, the sensor could be a simple tool for bartenders, friends or law enforcement to use, the researchers say.