Sensitive Fluorometric Detection of Fentanyl-Class Agents by Competition-Mediated Supramolecular Displacement and Graphene Nanoparticle Quenching

The emergence of synthetic opioids, and especially fentanyl and its analogues, has resulted in an epidemic of opioid abuse leading to a significant increase in overdose deaths in the United States, thus posing a threat to public health and safety. Current methods employed for the detection of fentanyl and its analogues have significant drawbacks in their sensitivity, scalability, and portability that limit use on a broader scale or in field-based application. The need to detect trace amounts of fentanyl in complex mixtures, and the continued emergence of new fentanyl analogues, further complicates these detection efforts. Accordingly, there is an urgent need to develop convenient, rapid, and reliable sensors for fentanyl detection. In this study, we have developed a fluorescent sensor based on the competitive displacement of a fluorophore (Hoechst 33342) from the cavity of a supramolecular macrocycle (cucurbit[7]uril), with subsequent fluorescence quenching from graphene quantum dots. This sensor can detect and quantify small quantities of fentanyl along with 58 fentanyl analogues, including detection of highly potent agents like carfentanil that are of increasing concern. Furthermore, the sensor achieves selective detection of these agents even when at 0.01 mol% in the presence of common interferents. In addition, the sensor provides results within seconds and offers stable performance over time. This simple, rapid, reliable, sensitive, and cost-effective sensor thus offers a valuable tool for detecting drugs in the fentanyl class, especially in the context of improving the effectiveness of field-based detection for law enforcement and military personnel in promoting public safety.