The illicit use of synthetic opioids, particularly fentanyl, has led to over 70% of overdose deaths, primarily due to its extremely low lethal dose of just 2 mg, according to the U.S. Centers for Disease Control and Prevention. This underscores the urgent need for sensitive detection methods to mitigate such outcomes. While several electrochemical techniques have been previously used to detect fentanyl, this study combines the Molecularly Imprinted Polymer (MIP) approach with Electrogenerated Chemiluminescence (ECL) to create a MIP-ECL sensor for fentanyl detection. This sensor offers several advantages, including high sensitivity and selectivity, and good stability and reproducibility. To fabricate the sensor, 4-amino benzoic acid (4-ABA) was electropolymerized on a glassy carbon electrode (GCE) in the presence of a standard fentanyl template, followed by the elution of bound fentanyl to form the MIP sensor. The ECL signals were generated with the sensor, where the target fentanyl bound on the MIP served as the coreactant, and [Ru(bpy)₃]²⁺ in phosphate buffer (pH 7.5) acted as the emitter, under anodic potential scanning from 0 to 1.6 V vs. Ag/AgCl. Key parameters such as template concentration, polymerization cycles, fentanyl elution, and rebinding times were optimized. The sensor demonstrated a limit of detection of approximately 1 μM, with a detectable fentanyl amount of around 4 ng. Overall, this MIP-ECL sensor exhibits excellent stability, responsiveness, selectivity, and reproducibility for fentanyl detection.

Schematic representation of MIP based ECL sensor for fentanyl detection

Jesy Motchaalangaram

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