PinIt almost sounds like something out of a science fiction movie; however, scientists have invented an alcohol sensing tattoo to detect blood alcohol concentration, giving law enforcement another non-invasive tool to try to curb DWIs and alcohol-related traffic accidents.

University of California San Diego (UCSD) professorial engineers Joseph Wang and Patrick Mercier have invented a temporary tattoo device that accurately measures an individual’s blood alcohol level from his/her perspiration. This flexible sensor transmits the reading—which usually takes only about 15 minutes to register—to a laptop, smart phone, tablet, or other mobile device. The genius of this item is that it is another non-invasive way that police officers and other authorities can monitor blood alcohol content (BAC) in real-time.

The Brains behind the Device

Wang and Mercier collaborated to invent the device. Wang’s team actually fabricated the device, constructed of “screen-printed electrodes and a small hydrogel patch containing pilocarpine, a drug that passes through the skin and induces sweat.” The induced sweat comes into contact with an alcohol oxidase-coated electrode that reacts with alcohol to create hydrogen peroxide which is then able to be detected electrochemically.

Mercier’s group created the flexible circuit board that provides the power to the device and facilitates Bluetooth communication with mobile devices. Mercier also developed the magnetic connector and the device’s mobile app.

The team is currently working on developing a similar device to continuously monitor BAC for 24 hours. This longer time frame would be beneficial for individuals who have been convicted of DWI/DUI and ordered to not consume any alcohol as part of their sentence.

How it Works

The device itself sticks to the skin and induces sweat, from which it can detect blood alcohol levels. A magnet connects the tiny, flexible electronic circuit board to the “tattoo” itself and operates via Bluetooth technology—something a breathalyzer cannot do.

There are two types of sweat—insensible and sensible. Insensible sweat is non-visible perspiration while sensible sweat is actual, visible perspiration on someone’s skin. Whereas BAC levels are not as accurate from insensible perspiration, sensible sweat is a far better real-time indicator of one’s BAC. Even though there has been technology able to obtain accurate BAC readings from sensible sweat, until now the devices were neither portable nor realistic for someone to actually wear.

A New Host of Benefits

Given the continually high rate of alcohol-related automobile accidents, this new technology—published recently in the American Chemical Society’s journal Sensors—provides another accurate, quick, convenient, and non-intrusive method for alcohol monitoring to curb driving while intoxicated. The device can also be integrated with an automobile’s ignition interlock system, friends could use the technology to ensure that they do not let a buddy drive drunk, or a person can simply monitor his/her own BAC while out drinking to ensure s/he does not get behind the wheel.

Test Outcomes

The sensor was tested on nine healthy volunteers who wore the device both before and after consuming alcohol, and the readouts obtained were an accurate measure of participants’ BACs. Further, the device wasn’t affected by the wearers’ movements.

A Replacement for Breath Tests?

Even though breathalyzers are the most commonly used methods for a quick test of a suspected DWI/DUI driver’s BAC, they are known for providing false and misleading readings depending upon when the breath sample was taken and/or if a suspect has tried to obtain a false negative by washing his/her mouth out before blowing.

Similar Endeavors

In March 2015, the National Institute on Alcohol Abuse and Alcoholism (NIAAA) held a Wearable Alcohol Biosensor Challenge and the response was impressive. First prize went to BACtrack, a company already known for designing and marketing its portable breath alcohol testers. The company’s BACtrack Skyn is worn on the wrist like a watch and provides continuous, non-invasive BAC monitoring utilizing fuel cell technology. Santa Barbara technology startup Milo came in second with its own wrist-worn wearable blood alcohol sensor that also pairs with a smart phone and operates with disposable cartridges to continually monitor the wearer’s BAC.

The UC San Diego engineers’ design essentially trumps these fine inventions because of its small, flexible design and more technologically advanced sensors.