Amperometric acetylcholine biosensor based on graphene-PEDOT:PSS modified electrode

A promising acetylcholine biosensor based on graphene-PEDOT:PSS (GR-PEDOT:PSS) and bienzyme, choline oxidase (ChOx) and acetylcholine esterase (AChE), modified electrode was successfully fabricated. GR-PEDOT:PSS ink was directly dropped on the screen printed carbon electrode (SPE), and then ChOx and AChE in the optimized loading ratio were immobilized on GR-PEDOT:PSS/SPE by the 10% glutar-aldehyde (GA) vapor cross-linked for 8 minutes. 1% Nafion was coated on the outermost layer of AChE-ChOx/GR-PEDOT:PSS/SPE for performing as a protective film. For amperometric responding, our acetylcholine biosensor showed a low limit detection, high linearity and sensitivity, which were 50 µM, 50 to 250 µM and 486.1 nA/mM, respectively, at −200 mV versus Ag/AgCl reference electrode. Moreover, this biosensor has a simple preparation, low-cost fabrication, and stable detection, thus it is a novel tool for acetylcholine determination.