神经接口在神经微电极的辅助下为生物信号调制和记录提供了窗口。然而,缩小电极的尺寸导致高电化学阻抗和低电容,从而限制了刺激/记录效率。为了实现临界稳定性和低功耗,在这里,提出了具有广泛表面积的纳米锥形铂(Pt)作为裸Pt衬底上的粘合层,然后沉积一层薄的氧化铱(IrOx)以制造高性能的基于纳米锥阵列的Pt-IrOx神经微电极(直径200μm)。通过控制电解液中NH4+和Pt4+离子的比例,形成具有显著粗糙度的均匀纳米锥形Pt,可广泛适用于多通道柔性微电极阵列(fMEAs)和不同尺寸的各种基板的批量生产。Pt-IrOx纳米复合材料涂覆的微电极在1kHz下呈现低至0.72±0.04Ωcm2的显着低阻抗(降低〜92.95%)。阴极电荷存储容量(CSCc)和电荷注入容量(CIC)分别达到52.44±2.53mCcm-2和4.39±0.36mCcm-2。此外,还观察到优异的慢性稳定性和生物相容性。修饰的微电极显著增强了小胶质细胞的粘附力,中枢神经系统的主要免疫细胞。因此,这种涂层策略为生物医学和其他实际应用提供了巨大的潜力。
Neural interfaces provide a window for bio-signal modulation and recording with the assistance of neural microelectrodes. However, shrinking the size of electrodes results in high electrochemical impedance and low capacitance, thus limiting the stimulation/recording efficiency. In order to achieve critical stability and low power consumption, here, nanocone-shaped platinum (Pt) with an extensive surface area is proposed as an adhesive layer on a bare Pt substrate, followed by the deposition of a thin layer of iridium oxide (IrOx) to fabricate high-performance nanocone-array-based Pt-IrOx neural microelectrodes (200 μm in diameter). A uniform nanocone-shaped Pt with significant roughness is created via controlling the ratio of NH4+ and Pt4+ ions in the electrolyte, which can be widely applicable for batch production on multichannel flexible microelectrode arrays (fMEAs) and various substrates with different dimensions. The Pt-IrOx nanocomposite-coated microelectrode presents a significantly low impedance down to 0.72 ± 0.04 Ω cm2 at 1 kHz (reduction of ~92.95%). The cathodic charge storage capacity (CSCc) and charge injection capacity (CIC) reaches up to 52.44 ± 2.53 mC cm-2 and 4.39 ± 0.36 mC cm-2, respectively. Moreover, superior chronic stability and biocompatibility are also observed. The modified microelectrodes significantly enhance the adhesion of microglia, the major immune cells in the central nervous system. Therefore, such a coating strategy presents great potential for biomedical and other practical applications.