Variable Nanoelectrode at the Air/Water Interface by Hydrogel-Integrated Atomic Force Microscopy Electrochemical Platform

A nanoelectrode with a controllable area was developedusing commercialatomic force microscopy and a hydrogel. Although tremendous advantagesof small electrodes from micrometer scale down to nanometer scalehave been previously reported for a wide range of applications, preciseand high-throughput fabrication remains an obstacle. In this work,the set-point feedback current in a modified scanning ionic conductancemicroscopy system controlled the formation of electrodes with a nanometer-sizedarea by contact between the boron-doped diamond (BDD) tip and theagarose hydrogel. The modulation of the electroactive area of theBDD-coated nanoelectrode in the hydrogel was successively investigatedby the finite element method and cyclic voltammetry with the use ofa redox-contained hydrogel. Moreover, this nanoelectrode enables thesimultaneous imaging of both the topography and electrochemical activityof a polymeric microparticle embedded in a hydrogel.