提出了一种三维凸起柔性神经微电极阵列的制作方法。该方法以光敏性聚酰亚胺(Durimide 7510)为基质材料,以各向异性刻蚀的硅为模具,结合微注模、金属微图形化和牺牲层电化学释放技术制作三维凸起柔性微电极,并通过数值模拟、形貌观测和电学性能测试对制备的微电极进行了评价。利用上述方法制备了具有4×4电极位点阵列的三维柔性神经微电极,每个电极位点大小为60μm×60μm,高度约37μm。阻抗测试显示,1 kHz时三维凸起电极位点的阻抗比传统的相同大小的平面微电极阵列约降低63%。结果表明,该电极的凸起特点可以保证电极刺激位点与神经细胞的良好接触,同时凸起结构也增加了电极刺激位点的表面积,改善了电极刺激位点的电荷注入能力,可有效提高刺激效果。

A fabricating method for the flexible 3D protruding Microelectrode Arrays(MEAs) for neural applications was proposed.This method used a photosensitive polyimide(Durimide 7510) as substrate and an anisotropically etched Si as mold to fabricate a flexible pyramid-shaped microelectrode array by combining a micro-molding technique,a metallic patterning and an electrochemical-based sacrificial layer technique.An evaluation for 3D protruding electrode was also performed by simulation,SEM and resistance test,and the 3D flexible polyimid-based microelectrode with 4 × 4 array of electrode sites was fabricated using the proposed method,in which each individual electrode site has base area of 60 μm×60 μm and the height of 37 μm in pyramid shaped tip.Compared with conventional planar microelectrodes in the same base area,the electrode impedance of 3D pyramid-shaped microelectrode decreases by 63%.The results show that the pyramid-shaped electrode configuration allows electrode sites to be close to target neurons.On the other hand,the pyramid-shaped configuration can reduce electrode impedance and increase charge injection,which is helpful to neural stimulation.