Microfabrication of Surgically Compatible Retinal Implant for the Blind

0001296 Wyatt该SGER项目将开发三种工艺，以集成到一个单一的制造序列中，该序列需要一个可测试的盲人设备原型，使他们能够在没有帮助的情况下走在街上。在这个水平上，视力的提高更多地取决于有足够宽的视野，而不是以高敏锐度分辨小物体或文本的能力。将进行三个实验以确定用于制造可膨胀视网膜假体的基本步骤是可行的。还需要验证的聚酰亚胺层，虽然不足以保护CMOS电路对盐水，是足够的绝缘金引线从电流分流在延长浸泡tests.The第一个实验是要确定的最终可实现的长度的微通道的高度和宽度的氧化物条纹的蚀刻后产生的通道的依赖关系。这将决定所需的3-5 mm长度是否需要同时从器件的两端进行蚀刻，或者单端蚀刻是否足够。第二个实验是开发一种可行的工艺，用于创建提案中所示的硅“笔尖”结构（图2）。这将涉及博世工艺中的多步蚀刻、快速硅蚀刻系统和常规RIE工具。必须为该过程开发适当的掩蔽材料，并确定终点指标。第三个实验是开发一种合适的方法，用于将携带压缩空气的硅胶管以blocompatible方式连接到硅/聚酰亚胺植入物结构。在这些工艺开发步骤的同时，将测试已经制造的聚酰亚胺电极，以确定它们的耐盐性是否足以保护金线。制造实验将由道格拉斯夏尔博士在纽约州伊萨卡市的美国国家科学基金会资助的康奈尔纳米纤维设施（CNF）进行，他是一名独立承包商，在过去两年中一直与PI合作进行视网膜植入项目。 现有聚酰亚胺阵列的浸没测试将在PI的监督下在MIT的德雷珀实验室进行。CNF和MIT测试系统能够完成这项工作。它的成功完成将为解决柔性可膨胀视网膜假体的长期生物相容性，封装和功率转换问题的详细提案提供概念验证。 这项调查产生的概念验证将被用作非SGER提案的基础，该提案将接受全面的价值审查。

0001296WyattThis SGER project would develop three processes for integration into a single fabrication sequence needed for a testable prototype of a device for blind patients to allow them to walk down a street unaided. Improved vision at this level depends more on having a sufficiently wide visual field than on the ability to resolve small objects or text with high acuity. Three experiments are to be conducted to establish that the basic steps for fabricating the inflatable retinal prosthesis are feasible. Also needed is verification that the polyimide layer, though not adequate to protect CMOS circuitry against saline, is adequate to insulate gold leads from current shunting in extended soak tests.The first experiment is to determine the dependence of the ultimate achievable length of the microchannels on the height and width of the oxide stripes which give rise to the channels after etching. This will determine whether the 3-5 mm length required will necessitate etching from both ends of the device simultaneously, or whether single-ended etching will be sufficient. The second experiment is to develop a workable process for creating the silicon "nib" structure shown in the proposal (Figure 2). This will involve multiple-step etching in a Bosch process rapid silicon etching system and conventional RIE tools. An appropriate masking material for the process must be developed, and an endpoint indicator determined. The third experiment is to develop a suitable method for attaching the silicone tube carrying the compressed air to the silicon/polyimide implant structure in a blocompatible manner. In parallel with these process development steps, the polyimide electrodes already fabricated would be tested to determine if their saline resistance is adequate for protecting the gold wires.The fabrication experiments are to be conducted at the NSF-funded Cornell Nanofabrication Facility (CNF) in Ithaca, NY by Dr. Douglas Shire, an independent contractor who has been collaborating with the PI on the Retinal Implant Project for the past two years. Immersion testing of existing polyimide arrays will be done at MIT's Draper Laboratory under the supervision of the PI. The CNF and the MIT test system are capable of carrying out the work. Its successful completion will provide the proof-of-concept for a detailed proposal addressing the long-term biocompatibility, encapsulation and power conversion issues for a flexible, inflatable retinal prosthesis. A proof-of-concept resulting from this investigation would be used as the basis of a non-SGER proposal, which would be subject to full merit review.