Etomidate rapid detection by enzyme-linked immunosorbent assay combined with aggregation-induced emission luminogens

A novel water-soluble AIE luminogen (TPE-phos) enabled enzyme-triggered fluorescence turn-on. • Dual visual/spectrofluorometric readout sensing platform combined AIE and conventional ELISA. • Etomidate was detected at 3.52 ng/mL with excellent linearity (R 2  = 0.9916). • Excellent specificity, <5% variation at 24h, and applicability to forensic testingof small molecules. Concealed drug abuse and delayed detection hinder global drug control efforts, necessitating rapid, on-site point-of-care detection methods. Here, we report a sensitive and practical aggregation-induced emission (AIE)-ELISA method for the quantitative detection of etomidate (ETO)—an emerging drug of abuse—in biological matrices. A water-soluble tetraphenylethylene derivative, TPE-phos, was designed and synthesized as an efficient alkaline phosphatase (ALP) substrate. In the competitive ELISA format, ALP-catalyzed hydrolysis of TPE-phos generates the poorly water-soluble TPE-OH, which spontaneously aggregates and produces strong fluorescence enhancement, enabling sensitive signal readout. The method exhibits a linear range of 0–125 ng/mL (R 2  = 0.9916) and a limit of detection of 3.52 ng/mL. Satisfactory spike recoveries were obtained in artificial urine and saliva, confirming robustness in complex biological matrices. The proposed method offers a compelling balance of sensitivity, operational simplicity, and cost-effectiveness, making it a practical tool for point-of-care ETO screening in public safety and forensic contexts. Download: Download high-res image (158KB) Download: Download full-size image