Electrodeposition-Optimized PEDOT Interfaces on Printed Circuit Boards for Stable, Low-Impedance Organoid Electrophysiology

Reliabl electrophysiological sensing in brain organoids is limited by the high interfacial impedance and noise of microscale electrodes, particularly when scalable and reusable platforms are required. In this work, we introduce PEDOT-coated printed circuit board (PCB) electrodes as a biosensing platform for low-noise recording of organoid electrical activity. Conducting polymer coatings were electrodeposited directly onto PCB-integrated electrodes and systematically optimized to maximize interfacial capacitance while preserving coating adhesion and durability. The optimized PEDOT interfaces reduced electrode impedance to 3-5 kΩ at 1 kHz, corresponding to about three-order-of-magnitude decrease compared to Au-coated electrodes. The low-impedance response was retained after repeated autoclave sterilization and sonication, demonstrating robustness under conditions relevant to routine biological use. When applied to human brain organoids, the PEDOT-coated electrodes exhibited markedly reduced background noise and significantly enhanced signal-to-noise ratios (SNR), enabling reliable detection of extracellular spikes and synchronized burst activity across multiple channels. Relative to gold electrodes, the PEDOT-modified PCB platform recorded higher-amplitude signals and increased spike counts, indicating improved electrode-tissue coupling. These results establish PEDOT-coated PCB electrodes as a scalable and reusable biosensing interface for electrophysiological interrogation of 3D neural tissues.