Printed Sensors Provide on the Spot Fentanyl Detection

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Researchers at the University of California San Diego have developed screen-printed sensors that could offer a faster, convenient and low-cost method to detect the drug fentanyl. The sensors can detect micromolar concentrations of fentanyl in just one minute. They are easy to produce, cost only a few cents apiece, and are disposable.

First responders, law enforcement officers and postal workers could use them to quickly and easily detect fentanyl in the field or workplace and avoid potentially dangerous exposures.

Current methods to classify unknown drug samples, including fentanyl, are costly and primarily done in a lab. The new sensors could allow simple, on the spot detection with disposable strips, similar to those used to monitor blood glucose, researchers said.

The work, led by Joseph Wang, a professor of nanoengineering and the director of the Center for Wearable Sensors at the UC San Diego Jacobs School of Engineering, was published in Analytical Chemistry.

The sensors work via electrochemical detection. They identify chemicals based on the voltage at which compounds are oxidized or reduced, causing a spike in electric current. And this spike generates a unique signature that researchers could use to identify drug agents like fentanyl.

Wang’s team created the sensors by screen printing electrodes onto thin polymer sheets—made of the same material used for plastic bottles and food packaging. The electrodes are treated with an ionic liquid to stabilize them and help fentanyl samples accumulate on the surface.

Screen printing drives down the cost of the technology. Each sensor costs just a few cents to make. Handheld spectrometers currently used for drug detection can cost up to tens of thousands of dollars. The sensors can also be screen printed onto fabric and other materials, making it possible for law enforcement officers to wear them on a sleeve.

In tests, the researchers applied laboratory samples of fentanyl to the sensor strips and inserted them into a handheld electrochemical analyzer. The analyzer transmits the data to a computer or tablet. Right now, researchers need to process the results on a computer in order to determine the presence and concentration of fentanyl.

The team is refining their method to produce direct readouts on the screen. They are also working on sensors that could analyze more complex drug samples.