Dual-mode colorimetric and chemiluminescence aptasensor for organophosphorus pesticides detection using aptamer-regulated peroxidase-like activity of TA-Cu.

The residues of organophosphorus pesticides (OPs) in food pose a huge threat to human health. Therefore, the development of detection methods with simple design and high sensitivity is urgently needed. Here, a colorimetric/chemiluminescence (CL) dual-mode aptasensor strategy with high selectivity and sensitivity for detecting Parathion-methyl (PM) was designed based on aptamer-regulated nanozyme activity. The Parathion-methyl specific aptamer was anchored onto the surface of trimesic acid-Cu (TA-Cu) nanozyme, which can regulate the catalytic ability of TA-Cu nanozyme towards substrates and also serve as a specific recognition unit for PM. In the presence of PM, the aptamers bind to PM and detach from the surface of TA-Cu nanozyme, which effects the catalytic ability of TA-Cu nanozyme towards substrates. Based on the above experimental phenomena, a colorimetric/CL dual-mode aptasensor method for PM was developed, with the linear ranges of 0.01-20 and 1-100 ng/mL, the limit of detections of 0.004 and 0.45 ng/mL, respectively. More importantly, compared with most single mode analysis methods, this dual-mode sensing system can conduct self-inspection by comparing the detection results of each mode, thus improving the reliability of the detection results.