The surface morphology of PAIUCPE, IUCPE and bare nichrome electrode were characterized by scanning electron microscope (SEM). There were long and narrow grooves on the surface of bare nichrome electrode (Fig. 1A). However, this much porosity was enough for carbon paste inlay to fabricate an inlaying ultrathin carbon paste electrode (IUCPE) with a layer thickness of carbon paste film at nanometer level (Fig. 1B). The calculation indicated that the thickness of the carbon paste film was about 100 nm. The SEM of PAIUCPE (Fig. 1C) revealed that flake structures of graphite got smaller and some chips of graphite form three-dimensional gaps withmulti-hole, whichcouldeffectively increase the apparent electroactive surface area ofthe electrode and significantly improve the electrochemical performance on analyte.