Graphene and Poly(3,4-ethylenedioxythiophene)-Polystyrene Sulfonate Hybrid Nanostructures for Input/Output Bioelectronics

The ability to senseand stimulate cellular and tissue electrophysiologyis fundamental to input/output bioelectronics. Their functionalityis primarily governed by the structural and functional propertiesof the constituent electrode materials. Conventional electrode materialsare hindered by their two-dimensional topology, high electrochemicalimpedances, low charge injection capacities, and limited stabilityover chronic timescales. Here, we propose a strategy for obtaininghigh-surface-area hybrid-nanomaterial for efficient I/O bioelectronicsby conformally templating conductive polymer poly-(3,4-ethylenedioxythiophene)-polystyrenesulfonate (PEDOT:PSS) onto nanowire-templated three-dimensional (3D)fuzzy graphene (NT-3DFG). The result is a high-performance electrodematerial that can leverage the exceptional surface area of NT-3DFGand the volumetric charge storage properties of PEDOT:PSS. Owing toits high surface area, NT-3DFG microelectrodes exhibit lower electrodeimpedance and up to 35-fold greater charge injection capacity (CIC)compared to conventional metal microelectrodes. Conformally templatingPEDOT:PSS onto NT-3DFG further reduces electrode impedance and enhancesCIC by 125-fold compared to conventional metal microelectrodes. Moreover,the NT-3DFG-based nanomaterials exhibit high functional stability.Our results highlight the importance of extrapolating electrode topographyto 3D and developing hybrid nanomaterials for miniaturized microelectrodesfor functional bioelectronics.