Pt single-atom catalyst-Enhanced aerogenous reaction for pressure signal-based immunochromatographic test strip

The illicit proliferation of fentanyl, a synthetic opioid drug with extremely strong addiction, has triggered severe public health crisis and social challenge. Conventional detection methods for this drug usually suffer from insufficient sensitivity and operational complexity. Herein, a single-atom catalyst (SAC)-driven pressure sensing strategy was developed by integrating amorphous Fe₂O₃-supported Pt SAC with immunochromatographic test strip for sensitive immunoassay of fentanyl. The unique twisted structure of Fe₂O₃ carriers provides large specific surface area and numerous defective sites for anchoring the metallic active sites. Pt SACs were anchored onto the carriers via robust Pt-O coordination bonds, endowing the improved loading stabilization and extremely high utilization efficiency of active sites. Compared to regular Pt nanoparticles, this Pt SAC-based pressure signal tag possesses superior catalase-like activity, decomposing hydrogen peroxide with 5-time faster aerogenous kinetics. Thus this immunochromatographic test strip using Pt SAC as signal tag exhibits extremely high sensitivity with a detection limit of 2.97 pg mL^-1. Fentanyl in urine, saliva, and electronic cigarette liquid was detected with recoveries of 82.10 %-117.5 %, verifying its reliability for real sample detection. It is a pioneer work for usage of SAC in boosting aerogenous reaction for pressure sensing, and opens a pathway for field screening of abused drug.