Optimization of pillar electrodes in subretinal prosthesis for enhanced proximity to target neurons.
Optimization of pillar electrodes in subretinal prosthesis for enhanced proximity to target neurons.
复制标题
视网膜下假体中的支柱电极的优化，以增强靶向神经元的邻近性。
DOI：
10.1088/1741-2552/aaac39
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发表时间：
2018-06
影响因子：
4
通讯作者：
Palanker D
中科院分区：
文献类型：
--
作者：
Flores T;Lei X;Huang T;Lorach H;Dalal R;Galambos L;Kamins T;Mathieson K;Palanker D
高分辨率的人工视觉需要密集的刺激阵列和小电极。然而，这种小型化降低了电极电容和电场到组织中的穿透。我们评估潜在的解决方案，这些问题与视网膜下植入物的基础上利用柱电极。为了研究三维（3D）植入物与视网膜组织的整合，我们制造了具有不同柱直径、节距和高度的阵列，并植入大鼠的退化视网膜下方（皇家外科学院，RCS）。术后6周使用组织学和整体包埋共聚焦荧光成像评价组织整合。在COMSOL中计算由各种电极配置产生的电场，并使用网络介导的视网膜反应模型评估刺激阈值。视网膜组织迁移到支柱之间的空间，在90%的植入阵列中没有可见的神经胶质增生。10 μm高的柱体到达内核层的中部，而22 μm高的柱体到达内核层的上部。具有圆顶形帽的电镀柱增加了活性电极表面积。将溅射的氧化铱选择性沉积到盖上确保了电流注入到柱顶部的局部化，从而避免了绝缘柱侧壁的需要。根据计算模型，与具有周向返回的平面阵列相比，具有在INL上方的阴极返回电极和在植入物表面处的活性阳极环形电极的柱将实现低6倍的刺激阈值，但是遭受相邻像素之间的更大串扰。视网膜下假体中的3D电极有助于减少电极-组织分离并降低刺激阈值，以实现更小的像素，从而提高假体视觉的视敏度。
High-resolution prosthetic vision requires dense stimulating arrays with small electrodes. However, such miniaturization reduces electrode capacitance and penetration of electric field into tissue. We evaluate potential solutions to these problems with subretinal implants based on utilization of pillar electrodes. To study integration of three-dimensional (3D) implants with retinal tissue, we fabricated arrays with varying pillar diameter, pitch, and height, and implanted beneath the degenerate retina in rats (Royal College of Surgeons, RCS). Tissue integration was evaluated 6 weeks post-op using histology and whole-mount confocal fluorescence imaging. The electric field generated by various electrode configurations was calculated in COMSOL, and stimulation thresholds assessed using a model of network-mediated retinal response. Retinal tissue migrated into the space between pillars with no visible gliosis in 90% of implanted arrays. Pillars with 10 μm height reached the middle of the inner nuclear layer (INL), while 22 μm pillars reached the upper portion of the INL. Electroplated pillars with dome-shaped caps increase the active electrode surface area. Selective deposition of sputtered iridium oxide onto the cap ensures localization of the current injection to the pillar top, obviating the need to insulate the pillar sidewall. According to computational model, pillars having a cathodic return electrode above the INL and active anodic ring electrode at the surface of the implant would enable 6 times lower stimulation threshold, compared to planar arrays with circumferential return, but suffer from greater cross-talk between the neighboring pixels. 3D electrodes in subretinal prostheses help reduce electrode-tissue separation and decrease stimulation thresholds to enable smaller pixels, and thereby improve visual acuity of prosthetic vision.
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影响因子：
1.8
作者：
Jung, Jae-Hyun;Aloni, Doron;Yitzhaky, Yitzhak;Peli, Eli
通讯作者：
Peli, Eli
影响因子：
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Picaud, S.
影响因子：
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通讯作者：
Palanker, Daniel
影响因子：
5.3
作者：
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通讯作者：
Marc RE
影响因子：
3
作者：
Ahuja, A. K.;Yeoh, J.;daCruz, L.
通讯作者：
daCruz, L.