Afterglow time-resolved lateral flow immunoassay platform with a low-cost handheld reader for on-site detection of methamphetamine

Methylamphetamine (methamphetamine, MET) is a highly addictive drug worldwide. In drug abuse screening, point-of-care detection is crucial for addiction treatment and rehabilitation centers, as well as law enforcement agencies. Among various point-of-care detection methods, lateral flow immunoassay (LFIA) has garnered widespread attention due to its unique advantages of ease of use and speed. However, conventional colloidal gold-based LFIA can only perform qualitative or semi-quantitative detection, while most quantitative LFIAs based on optical nanoprobes require expensive equipment to read signals, limiting broader adoption. In this study, we developed a novel afterglow time-resolved fluorescence LFIA (AG-LFIA) technology that enables on-site quantitative detection of MET in urine through a custom-developed miniature sensing device. Considering product development and commercialization, a one-step coprecipitation method and an in-situ self-assembly method were established to prepare afterglow probes in large quantities for scalable production. The proposed AG-LFIA sensing strategy effectively eliminates interference from endogenous biological signals and excitation light. Furthermore, leveraging the afterglow properties, an integrated fluorescence signal amplification and collection strategy was introduced, which improves the signal-to-noise ratio and obviates the requirement for intricate optical configurations and filters in traditional optical readers. As a result, the AG-LFIA achieved an MET detection range of 4–10000 ng/mL, with a limit of quantification (LoQ) of 4 ng/mL and a detection time of 10 min. The AG-LFIA is user-friendly, highly sensitive, and accurate, making it an effective candidate for real-time drug abuse screening.