Components in neural implants, such as the electrode array and stimulator circuit, are often fabricated discretely. This modular fabrication scheme offers flexibility during development but poses difficulties during assembly, as components must be compactly integrated for implantation. It is particularly difficult in cases where the electrode array is required to have a high number of channels, such as in retinal prostheses. This paper presents the development of a parylene C‐based, double‐sided microelectrode array with 294 hemispheric electrodes for subretinal stimulation. The bonding pads on the bottom side of the double‐sided array are connected with electrodes through vias, eliminating the interconnection lines. The array can be integrated with a stimulator circuit through pad‐to‐pad bonding, resulting in a compact implant. The hemispheric electrodes are fabricated using thermally reflowed photoresist infillings, through which the height and width of the hemispheres can be easily controlled. The long‐term stability and biocompatibility of the materials and methods used to fabricate and package the electrodes are demonstrated in in vitro and in vivo environments over months. Finally, subretinal stimulation by the developed electrodes is successfully demonstrated using in vitro retinal patches from mice and monkeys.

中文翻译：

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用于视网膜下刺激的带有半球电极的双面薄膜微电极阵列

神经植入物中的组件，例如电极阵列和刺激器电路，通常是离散制造的。这种模块化制造方案在开发过程中提供了灵活性，但在组装过程中却带来了困难，因为组件必须紧凑地集成才能植入。在电极阵列需要具有大量通道的情况下（例如在视网膜假体中），这尤其困难。本文介绍了一种基于聚对二甲苯 C 的双面微电极阵列的开发，该阵列具有 294 个半球电极，用于视网膜下刺激。双面阵列底部的焊盘通过过孔与电极连接，消除了互连线。该阵列可以通过焊盘到焊盘的粘合与刺激器电路集成，从而形成紧凑的植入物。半球电极是使用热回流光刻胶填充物制造的，通过它可以轻松控制半球的高度和宽度。用于制造和包装电极的材料和方法的长期稳定性和生物相容性在体外和体内环境中经过数月的验证。最后，使用小鼠和猴子的体外视网膜斑块成功证明了所开发电极的视网膜下刺激。