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

The ability to sense and stimulate cellular and tissue electrophysiology is fundamental to input/output bioelectronics. Their functionality is primarily governed by the structural and functional properties of the constituent electrode materials. Conventional electrode materials are hindered by their two-dimensional topology, high electrochemical impedances, low charge injection capacities, and limited stability over chronic timescales. Here, we propose a strategy for obtaining high-surface-area hybrid-nanomaterial for efficient I/O bioelectronics by conformally templating conductive polymer poly(3,4-ethylenedioxythiophene)–polystyrene sulfonate (PEDOT:PSS) onto nanowire-templated three-dimensional (3D) fuzzy graphene (NT-3DFG). The result is a high-performance electrode material that can leverage the exceptional surface area of NT-3DFG and the volumetric charge storage properties of PEDOT:PSS. Owing to its high surface area, NT-3DFG microelectrodes exhibit lower electrode impedance and up to 35-fold greater charge injection capacity (CIC) compared to conventional metal microelectrodes. Conformally templating PEDOT:PSS onto NT-3DFG further reduces electrode impedance and enhances CIC 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 topography to 3D and developing hybrid nanomaterials for miniaturized microelectrodes for functional bioelectronics.