University of Texas at Dallas researchers have developed a first-of-its-kind, handheld electrochemical sensor that can accurately detect fentanyl in urine within seconds. UT Dallas researchers are working to advance the technology to detect fentanyl in hair. Their ultimate aim is to develop a test to detect fentanyl in saliva. To capture fentanyl with an electrochemical sensor, researchers used a molecular cagelike structure they compared to a mousetrap. The fentanyl sensor was developed in collaboration with EnLiSense, an Allen, Texas, company that develops lifestyle-based sensors and devices.