Electrochemical sensor for rapid detection of fentanyl using laser-induced porous carbon-electrodes

The growing pervasiveness of opioid-based drugs such as fentanyl and its analogs represent a foremost hazard to the civilian population and burden on the first responders and clinicians. Thus, to enable a rapid and low-cost surveillance system to detect fentanyl in a non-ideal environment, we demonstrate the use of laser-induced nano-porous carbon structures directly onto commercially available polyimide sheets for rapid and cost-effective manufacturing of electrochemical sensors for fentanyl detection. The porous carbon surface instigated by various laser energy densities was analyzed towards morphological, vibrational, and fentanyl sensing properties. The results showed that laser carbonized electrode (LCE) prepared with 31 J/cm² laser energy densities showed the highest level of porosity, surface roughness, and thereby enhanced sensitivity towards fentanyl detection by square-wave voltammetry (SWV) with a 1 µM limit of detection. This new disposable sensor strip offers an information-rich electrochemical fingerprint of fentanyl oxidation at + 0.526 V (vs Ag/AgCl) on the surface of laser carbonized electrodes with high linear (R² = 0.99) sensitivity (0.025 µA⋅µM^-1⋅cm^-2) and reproducibility (RSD = 5%), within the clinically relevant working range of 20-200 µM with similar performance in both PBS and serum samples. The laser carbonized electrode surface was further found to be selective towards fentanyl concentrations in the presence of various cutting agents. This technology could provide a new route towards scalable manufacturing of cost-effective sensors for rapid detection of opioid misuse and potentially save the lives from systemic side effects.