Aptamer-Based Fentanyl Detection in Biological Fluids.

Fentanyl is a widely abused analgesic and anesthetic drug with a narrow therapeutic window that creates easy opportunities for overdose and death. Rapid, accurate, and sensitive fentanyl detection in biosamples is crucial for therapeutic drug monitoring and overdose diagnosis. Unfortunately, current methods are limited to either sophisticated laboratory-based tests or antibody-based immunoassays, which are prone to false results and are mainly used with urine samples. Here, we have utilized library-immobilized SELEX to isolate new aptamers─nucleic acid-based bioreceptors that are well-suited for biosensing─that can specifically bind fentanyl under physiological conditions. We isolated multiple aptamers with nanomolar affinity and excellent specificity against dozens of interferents and incorporated one of these into an electrochemical aptamer-based sensor that can rapidly detect fentanyl at clinically relevant concentrations in 50% diluted serum, urine, and saliva. Given the excellent performance of these sensors, we believe that they could serve as the basis for point-of-care devices for monitoring fentanyl during medical procedures and determining fentanyl overdose.