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Abstract: The interfacial performance of implanted neural electrodes is crucial for stimulation safety and the recording quality of neuronal activity. This paper proposes a novel surface architecture and optimization strategy for the platinum–iridium (Pt–Ir) electrode to optimize electrochemical performance and wettability. A series of surface micro/nano structures were fabricated on Pt–Ir electrodes with different combinations of four adjustable laser-processing parameters. Subsequently, the electrodes were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy, and wetting behavior. The results show that electrode performance strongly depends on the surface morphology. Increasing scanning overlap along with moderate pulse energy and the right number of pulses leads to enriched surface micro/nano structures and improved electrode performance. It raises the maximum charge storage capacity to 128.2 mC/cm2 and the interface capacitance of electrodes to 3.0 × 104 μF/cm2 for the geometric area, compared with 4.6 mC/cm2 and 443.1 μF/cm2, respectively, for the smooth Pt–Ir electrode. The corresponding optimal results for the optically measured area are 111.8 mC/cm2 and 2.6 × 104 μF/cm2, which indicate the contribution of finer structures to the ablation profile. The hierarchical structures formed by the femtosecond laser dramatically enhanced the wettability of the electrode interface, giving it superwicking properties. A wicking speed of approximately 80 mm/s was reached. Our optimization strategy, leading to superior performance of the superwicking Pt–Ir interface, is promising for use in new neural electrodes.

清华大学姜长青、李路明等 | 飞秒激光结构化的层级铂铱神经电极具有超芯吸界面和优异的电荷存储能力