为了实现电极位点与靶细胞的良好接触,改善刺激效果,同时保证刺激电极的自身安全,提出了一种具有圆滑外形的丘形柔性神经刺激微电极阵列。以光敏性聚酰亚胺(Durimide 7510)为基质材料,利用光刻和金属层图形化结合电镀工艺,制作了6×6丘形柔性神经刺激微电极阵列,每个电极位点底面直径为150 μm,高度约为50 μm。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。实验结果表明:相对于传统的平面微电极阵列(具有相同底面积),三维丘形电极位点的阻抗(@1kHz)降低了约4倍,可实现更有效的刺激;而相对于塔形电极,丘形电极则具有更均匀的表面电流密度分布,保证了电极长期工作的安全性。

In order to enhance the contact between electrode sites and target neurons,improve the stimulation efficiency and reduce the electrochemical erosion of electrodes,dome-shaped flexible neural microelectrode arrays (MEAs) for neural stimulation were proposed. By using photosensitive polyimide (Durimide 7510) as its substrate,a flexible microelectrode with a 6 × 6 array of dome-shaped electrode sites was fabricated by combining the photolithography and the metal-patterning with electroplating process,in which each electrode site has a diameter of 150 μm and a height of 50 μm. An evaluation of the dome-shaped electrode was also performed by simulation,SEM and electrical characters. Experimental results show that the electrode impedance of the 3D dome-shaped microelectrodes has decreased by 80% as compared with those of conventional planar microelectrodes with the same base area.Moreover,the dome-shaped electrodes can produce more uniform current distribution than that of the 3D pyramid-shaped microelectrodes,which is helpful for its stimalation effect and long-term safety.