Electrochemical aptasensor based on one step co-electrodeposition of aptamer and GO-CuNPs nanocomposite for organophosphorus pesticide detection

In this work, aptamer (Apt) immobilized on sensing interface utilizing one step co-electrodeposition technology was first proposed and applied in an electrochemical aptasensor to detect organophosphorus pesticide. This method was simple and facile, solving the complicated problem of aptasensor preparation process. Specifically, in the preparation of the electrodeposition solution, graphene oxide (GO) was used to connect aptamer modified with NH2, offering the basis for aptamer fixation. And, the introduction of Cu nanoparticles (CuNPs) into the Apt-GO mixed solution enhanced the conductivity of the electrodeposition film, leading to superior electrochemical performance. In addition, during electrodeposition of the prepared solution on screen-printed carbon electrode (SPCE) surface by CV technology, GO was electrochemically reduced to reduced graphene oxide (rGO), providing better electrical conductivity. The Apt/rGO-CuNPs composite coating was characterized using SEM and CV technique. Under the optimal experimental conditions, the low detection limit of 0.003 nM for profenofos, 0.3 nM for phorate, 0.03 nM for isocarbophos and 0.3 nM for omethoate were obtained. The aptasensor was also successfully applied for the analysis of phorate in vegetables. Because the developed aptasensor with simple preparation process had extremely good stability, high selectivity and great sensitivity, it would show great potential for other fields.