A Simple Fluorescent Aptasensing Setup Controlled by Hybridization Chain Reaction for Detection of Illegal Drug...

In this study, a simple and sensitive label-free fluorescent assay was developed for the detection of methamphetamine (MET) by utilizing a hybridization chain reaction (HCR) product as a signal amplifier. This strategy utilizes berberine (BER) as a fluorescent dye, serving as a molecular marker. The detection strategy is based on the disassembly of the HCR product resulting from the interaction of the aptamer with MET, which releases multiple single-stranded DNA (ssDNA) sequences. The fluorescent signal is significantly enhanced through the intercalation of BER into ssDNA regions. The linear concentration range for MET detection was achieved from 1 nM to 150 µM with a limit of detection (LOD) of 0.28 nM. Moreover, the sensor exhibited an excellent sensitivity and selectivity for MET detection in the complex biological matrices, including artificial tear fluid, saliva, and human serum. The notable sensitivity, simplicity, and robustness of this aptasensor indicate its significant potential for applications in doping control and detection of prohibited substances in sports.