Selection and electrochemical-sensor application of an DNA-aptamer for methyl parathion detection

Abstract

An aptamer-based electrochemical sensor for methyl parathion (MP) detection is herein reported. The modified magnetic beads-systematic evolution of ligands by enrichment (MB-SELEX) was used to select the MP aptamer. After 14 rounds of selection, the aptamer (MPapta-6) with high affinity for MP was obtained, and its dissociation constant (Kd) was 39.66 ± 14.73 μM. Using the MPapta-6, the ultra-sensitive electrochemical sensor based on PLL-BP and AuNPs was constructed. The linear range of MP was 1–105 pM and detection limit (LOD) was as low as 0.49 pM. In addition, the application of the sensor in water samples was verified, and the recovery rate was 96.6%–103.5%. The results from this study showed that this strategy could be applied in practical detection.