Aptamer-Based Microcantilever Sensor for O-ethyl S-[2(diisopropylamino)ethyl] methylphosphonothiolate, Sarin Detection and Kinetic Analysis

A novel method for O-ethyl S-[2(diisopropylamino)ethyl] methylphosphonothiolate (VX), sarin detection and kinetic analysis based on piezoresistive microcantilever aptasensor was proposed, where VX and sarin aptamers were immobilized on the microcantilever surface by biotin-avidin binding system. A linear relationship between the response voltage and the concentration of VX in the range of 2−60 μg L−1 was obtained, the linear regression equation was ΔUe = 0.886C − 1.039 (n = 5, R = 0.984, p < 0.001) and the detection limit was 2 μg L−1 (S/N ≥A linear relationship between the response voltage and the concentration of sarin in the range of 10−60 μg L−1 was obtained, the linear regression equation was ΔUe = 0.716C − 2.304 (n = 5, R = 0.996, p < 0.001) and the detection limit was 10 μg L−1 (S/N ≥The sensor showed no response for O-butyl methylphosphonochloridate, a structural analog of VX and sarin, indicating a high specificity and good selectivity. On this basis, a reaction kinetic model based on receptor-ligand binding and the relationship with response voltage was established. Response voltage (ΔUe) and response time (t0) obtained from the fitting equation on different concentrations of VX and sarin fitted well with the measured values.

Graphical abstractA novel method for VX and sarin detection and its kinetic analysis based on piezoresistive microcantilever aptasensor was proposed. Compared with the conventional enzyme biosensor, the microcantilever aptasensor could specifically recognize VX and sarin. Furthermore, a reaction kinetic model for piezoresistive microcantilever aptasensor was established. The model could well reflect the dynamic response of the sensor.Figure optionsDownload full-size imageDownload as PowerPoint slide