Development of Multifunctional Hierarchically Restructured Antibacterial Neural Interfacing Electrodes via Plasma‐Enhanced Atomic Layer Deposition of Zinc Oxide Thin Films

Next‐generation implantable neural‐interfacing devices are increasingly constrained by the coupled demands of electrode miniaturization, electrochemical performance, and implantation infection risk. Femtosecond laser–based hierarchical surface restructuring (HSR) technology has emerged as a scalable, manufacturing‐compatible platform for overcoming electrochemical performance limitations of conventional electrodes and (micro)electrode arrays by substantially increasing the electrochemically active surface area of electrode contacts. However, imparting antibacterial functionality to HSR electrodes without compromising electrochemical performance remains a critical challenge. We report a surface engineering strategy that integrates the HSR technology with plasma‐enhanced atomic layer deposition (PEALD) to controllably introduce antibacterial functionality. ZnO‐based ultrathin films were deposited using either oxygen PEALD (O‐PEALD), yielding stoichiometric ZnO, or oxygen–hydrogen PEALD (O‐H‐PEALD), producing a ZnO–Zn nanocomposite containing metallic Zn domains. While O‐PEALD films impart antibacterial activity under dark, aerobic conditions, they introduce a resistive barrier that degrades electrochemical performance. In contrast, O‐H‐PEALD films preserve and enhance electrochemical performance, while maintaining robust antibacterial efficacy against both Escherichia coli and Staphylococcus aureus . Collectively, this work establishes a scalable and commercially viable strategy for decoupling and optimizing electrochemical performance and antibacterial functionality in implantable neural interfacing electrodes, providing an antibiotic‐free pathway toward infection‐resistant, high‐performance neural interfaces suitable for long‐term clinical deployment.