Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea.
J Neural Eng. 2019 Aug 21;16(5):056016. doi: 10.1088/1741-2552/ab36ab.
Various retinal prostheses have been developed to restore the vision for blind patients, and some of them are already in clinical use. In this paper, we present a three-dimensional (3D) microelectrode array for a subretinal device that can effectively stimulate retinal cells.
To investigate the effect of electrode designs on the electric field distribution, we simulated various electrode shapes and sizes using finite element analysis. Based on the simulation results, the 3D microelectrode array was fabricated and evaluated in in vitro condition.
Through the simulation, we verified that an electrode design of square frustum was effective to stimulate with high contrast. Also, the 3D flexible and transparent microelectrode array based on silicon and polydimethylsiloxane was fabricated using micro-electro-mechanical system technologies. In in vitro experiments, the subretinally positioned 3D microelectrodes properly evoked spikes in retinal ganglion cells. The mean threshold current was 7.4 µA and the threshold charge density was 33.64 µC·cm per phase.
The results demonstrate the feasibility of the fabricated 3D microelectrodes as the subretinal prosthesis. The developed microelectrode array would be integrated with the stimulation circuitry and implanted in animals for further in vivo experiments.
为了帮助盲人恢复视力，已经开发出各种视网膜假体，其中一些已经在临床应用中。本文提出了一种用于视网膜下设备的三维（3D）微电极阵列，可有效刺激视网膜细胞。
为了研究电极设计对电场分布的影响，我们使用有限元分析模拟了各种电极形状和尺寸。基于模拟结果，制作了 3D 微电极阵列，并在体外条件下进行了评估。
通过模拟，我们验证了方截锥形电极设计可有效实现高对比度刺激。此外，还使用微机电系统技术制作了基于硅和聚二甲基硅氧烷的 3D 柔性透明微电极阵列。在体外实验中，3D 微电极在视网膜下位置适当引发了视网膜神经节细胞的尖峰。平均阈值电流为 7.4µA，阈值电荷密度为每个相位 33.64µC·cm。
结果表明所制作的 3D 微电极作为视网膜下假体具有可行性。开发的微电极阵列将与刺激电路集成，并植入动物体内进行进一步的体内实验。
