Development of acetylcholinesterase immobilized CMD (Carboxymethyldextran) chip-based sensor for the detection of nerve agent simulant parathion

Abstract

In this study, a carboxymethyldextran chip based sensor system is developed that selectively recognizes and binds nerve agent molecules used in chemical weapons. Nerve agents fall under the group of organophosphorus compounds and irreversibly inhibit the acetylcholinesterase enzyme (AChE). In this study, parathion was used as an organophosphorus compound. The effect of the parathion molecule on enzyme inhibition is similar to nerve agents. The first step to be applied before CMD (Carboxymethyldextran) chip surface enzyme immobilization is the surface activation. After the surface activation was completed, AChE enzyme solution was passed over the chip surface for 40 minutes. In this way, enzyme immobilization was performed on the chip surface and a surface selective to the parathion molecule was obtained. Analysis was performed for parathion samples in different concentrations in the range of 3.43x10-8-6.86x10-4 mol/L. When the analysis results were transferred to the calibration graph, a graphic close to the linear was obtained. The working range of the chip surface developed as a result of the analyzes was calculated as 3.43x10-8 - 6.86x10-4, the limit of detection (LOD) value was 3.79x10-8 and the limit of quantification (LOQ) value was 6.16x10-8. These results show that samples containing parathion at very low concentrations can be analyzed using the method we have developed.