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

ABSTRACT

A new method for O-ethyl S-[2-( diisopropylamino) ethyl] methylphosphonothiolate ( VX) , sarin detection and its kinetic analysis based on piezoresistive microcantilever aptasensor was developed, where VX, 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 2-60μg/L was obtained. The linear regression equation was △Ue=0. 886C-1. 039 (n=5, R=0. 984, p<0. 001) and the detection limit was 2μg/L ( S/N≥3 ) . A linear relationship between the response voltage and the concentration of sarin in the range of 10-60 μg/L was obtained, the linear regression equation was △Ue=0. 716C-2. 304 ( n=5, R=0 . 996 , p<0 . 001 ) and the detection limit was 10 μg/L ( S/N≥3 ) . The sensor showed no response for O-butyl methylphosphonochloridate, a structural analog of VX and sarin, which indicated high specificity and good anti-interference ability. On this basis, a reaction kinetic model based on receptor-ligand binding and the relationship with output voltage change was established. Response voltage (△Ue ) and response time( t0 ) were obtained from the fitting equation on different concentrations of VX, sarin fitted well with the measured values.