An acetylcholinesterase biosensor with high stability and sensitivity based on silver nanowire–graphene–TiO2 for the detection of organophosphate pesticides

An electrochemical acetylcholinesterase biosensor based on silver nanowire, graphene, TiO2 sol–gel, chitosan and acetylcholinesterase has been fabricated successfully for the detection of organophosphate pesticides. The outstanding electrical properties of silver nanowires and graphene, and moreover the self-assembly of these two nanomaterials make the biosensor highly sensitive. Simultaneously, the immobilization efficiency of the enzyme is greatly improved by the action of the TiO2 fixed matrix. Under optimum conditions, the biosensor exhibited excellent performance for the detection of dichlorvos with a linearity in the range of 0.036 μM to 22.63 μM and the detection limit was found to be 7.4 nM. The biosensor was highly reproducible and stable during detection and storage.