Three-dimensional electrode arrays for retinal prostheses: modeling, geometry optimization and experimental validation
Three-dimensional electrode arrays for retinal prostheses: modeling, geometry optimization and experimental validation
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DOI：
10.1088/1741-2560/8/4/046020
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发表时间：
2011-08-01
影响因子：
4
通讯作者：
Picaud, S.
中科院分区：
文献类型：
--
作者：
Djilas, M.;Oles, C.;Picaud, S.
提出了三维电极几何形状以提高旨在恢复盲人患者视力的视网膜假体的空间分辨率。我们在这里报告的结果，从一项研究中，有限元建模被用来设计和优化三维电极的几何形状。所提出的植入物表现出在其底部包含刺激电极的井状形状的阵列，而公共返回网格电极围绕植入物顶表面上的每个井。还考虑了在腔壁上延伸刺激电极和/或网格返回电极。优化的目标是找到最大化电刺激聚焦的模型参数，从而最大化电极阵列的空间分辨率。结果表明，与类似的电极尺寸的平面结构相比，具有30 μ m的井深的电极几何形状产生十倍的选择性增加。微制造电极阵列原型并植入营养不良大鼠中，以确定组织是否会如模型中假设的那样表现。组织学检查显示，视网膜双极细胞与电极结合良好，形成孤立的细胞簇。建模分析表明，刺激电流在电极井内受到干扰，导致对单个双极细胞簇进行选择性电刺激，从而形成具有更高空间分辨率的电极阵列。
Three-dimensional electrode geometries were proposed to increase the spatial resolution in retinal prostheses aiming at restoring vision in blind patients. We report here the results from a study in which finite-element modeling was used to design and optimize three-dimensional electrode geometries. Proposed implants exhibit an array of well-like shapes containing stimulating electrodes at their bottom, while the common return grid electrode surrounds each well on the implant top surface. Extending stimulating electrodes and/or the grid return electrode on the walls of the cavities was also considered. The goal of the optimization was to find model parameters that maximize the focalization of electrical stimulation, and therefore the spatial resolution of the electrode array. The results showed that electrode geometries with a well depth of 30 mu m yield a tenfold increase in selectivity compared to the planar structures of similar electrode dimensions. Electrode array prototypes were microfabricated and implanted in dystrophic rats to determine if the tissue would behave as hypothesized in the model. Histological examination showed that retinal bipolar cells integrate the electrode well, creating isolated cell clusters. The modeling analysis showed that the stimulation current is confounded within the electrode well, leading to selective electrical stimulation of the individual bipolar cell clusters and thereby to electrode arrays with higher spatial resolution.