Temporary Tattoo Sends Blood Alcohol Levels to Your Smartphone

The iontophoretic-biosensor induces and analyzes sweat and sends its results via Bluetooth. (Image courtesy of American Chemical Society.)

We’ve got wearables to track footsteps, heart rate, blood oxygen levels, and even your unborn child. Now, there’s a wearable to track how much you’ve had to drink. Engineers have developed a small biosensor patch that detects alcohol levels and uses Bluetooth to send its findings right to your smartphone.

A Sweat Tattoo

The engineers describe their device as a “temporary tattoo system along with flexible wireless electronics”, which seems about right if you’re into tattoos that look like printed circuit boards taped to your arm. What they mean is that the electrodes in the device were screen-printed on temporary tattoo paper, making for easy application and removal from the skin. The “flexible wireless electronics” part of the device is a PCB that controls the sensing operation and transmits the data over Bluetooth.

The wearable works using an iontophoretic-biosensing system. First, the device induces perspiration with a drug called pilocarpine. Then, it analyzes the resulting sweat to determine ethanol levels in the body, which correspond directly to the amount of alcohol consumed. Lastly, it sends the data to the user to evaluate whether or not it’s time for that last round.

Schematic diagram of constituents in the iontophoretic system (left) and of the reagent layer and processes involved in the amperometric sensing of ethanol on the working electrode (right). (Image and caption courtesy of ACS Sensors.)

Roughly 88,000 people die every year in the U.S. from alcohol-related causes. In 2014, alcohol impairment was the cause of almost 10,000 driving fatalities – nearly a third of all driving fatalities nationally. The new wearable aims to bring these numbers down, as the engineers believe that their device will offer a practical solution for personal alcohol monitoring.

“Measuring alcohol in sweat has been attempted before, but those technologies took 2-3 hours to measure alcohol levels,” said Patrick Mercier. “Our patch sends alcohol levels to your smartphone in just 8 minutes, making real-time alcohol monitoring possible, practical, and personal."

You can see full details of the device in ACS Sensors. To learn about another sensor that could save lives, check out Nanosensors Could Help Diagnose and Treat Cancerous Tumors.