Electrochemical Micromachining of PEDOT/SDS@Au Hybrids for Multifunctional Bioelectronic Interfaces

As a key element of bioelectronic interfaces, microelectrode miniaturization has brought great challenges in electrochemical performance, durability, etc. In order to meet the increasingly urgent needs of long-term reliable and multifunctional integration in practical applications, herein we report a hybrid film composed of poly(3,4-ethylenedioxythiophene)/sodium dodecyl sulfate (PEDOT/SDS) @gold (Au) nanocrystal achieved by an electrochemical approach on bare flexible microelectrodes (200 μm in diameter). Au nanocrystal provides an extensive electrochemically active surface and hence good adhesion for the deposition of PEDOT/SDS film. The as-prepared PEDOT/SDS@Au nanocrystal hybrids demonstrate dramatically reduced electrochemical impedance down to 1.83 kΩ at 1 kHz (reduction of 90.03%), compared to that of the bare microelectrode. The corresponding cathodic charge storage (CSCc) and charge injection capacity (CIC) are increased up to ∼51.82 and 5.03 mC cm–2, respectively. It shows superior mechanical and electrochemical stability under 10 min high-frequency sonication and 10 million continuous electrostimulation. As proof-of-concept, the functionalized hybrid microelectrode promotes excellent electro-biochemical sensing toward dopamine (DA), with a low detection limit of 12 nM. The remarkable utility of antibacterial properties toward Escherichia coli is also observed. These achievements represent a significant advance in multifunctional efficacious bioelectronic interfaces with universal applicability, presenting profound implications for future research and applications.