Development and Translation of novel SiC encapsulation thin film for chronic auditory nerve implant electrodes

摘要 一系列神经疾病现在正在研究或使用完全植入型 记录或调节人类大脑活动的电子系统。这些植入物是 目前使用包裹植入物并帮助保持身体的聚合物涂层进行保护 远离敏感电子设备的液体。脑植入物与复杂的三维 像犹他州电极阵列(UEA)这样的几何结构对当前的封装提出了挑战 技巧。对二甲苯已成为神经和生物医学封装的金标准 植入物由于其良好的生物相容性、电学性能和 化学惰性。然而，长期神经植入物的记录能力(&gt；6个月) 用对二甲苯包裹后显示出降解的迹象。为解决这个问题，我们建议 开发和评估新型碳化硅的性能和生物兼容性/安全性 基于封装，旨在延长长期稳定性和可植入寿命 密度犹他州倾斜电极阵列(HD-USEA)与传统 人工耳蜗植入电极。采用HD-USEA作为穿透听神经电极。 一种新型的颅内听觉假体，它以听神经为目标 脑干为了在目前的护理标准上显著提高听力表现， 人工耳蜗术(CI)(NIH 1UG3NS107688-01)。 由于其优异的性能，碳化硅在过去一直被用作封装和电极材料。 固有的材料特性。这种对生物医学领域来说是新的封装层将保留所有 聚对二甲苯的优点，同时利用碳化硅层的极高介电性能 制造出寿命更长、电性能更稳定的生物医学植入物。这一层 封装方案可以无缝地整合到我们现有的制造工艺流程中 对于我们的旗舰产品，UEA。这种封装将适用于不同的表面(金属， 半导体、聚合物、陶瓷)和具有集成无线组件的设备 适用于长期植入的任何复杂医疗设备的涂层。我们的预赛 碳化硅包覆UEA的结果非常有希望支持所提出的工作。我们 已经表明，碳化硅产生更稳定的泄漏电流和稳定的阻抗(与 &lt；5%的变化。这种优越的性能暗示了它在慢性植入物中的潜在用途 具有复杂的表面几何形状。

Abstract A range of neurological diseases are now being researched or treated using fully implantable electronic systems to either record or modulate brain activity in humans. These implants are currently being protected using polymer coatings that envelop the implant and help keep body fluids away from the sensitive electronics. Brain implants with complex three-dimensional geometries, like the Utah Electrode Array (UEA) provide a challenge for current encapsulation techniques. Parylene has been the gold standard for encapsulation of neural and biomedical implants in general due to its well-suited combination of biocompatibility, electrical properties and chemical inertness. However recording capabilities of long-term neural implants (>6 months) encapsulated with Parylene show signs of degradation. To address this problem, we propose to develop and evaluate performance and biocompatibility/safety of a new Silicon Carbide (SiC) based encapsulation designed to extend the long term stability and implantable lifetime for a high density Utah Slant Electrode Array (HD-USEA) in line with lifetime expectations for conventional cochlea implant electrodes. The HD-USEA is used as penetrating auditory nerve electrode in a new type of intracranial auditory prosthesis that targets the auditory nerve en route to the brainstem in order to substantially improve hearing performance over the current standard of care, the cochlear implant (CI) (NIH 1UG3NS107688-01). SiC has been studied in the past as encapsulation and electrode material due to its outstanding inherent material properties. This encapsulation layer, novel to biomedical field, will retain all the advantages of Parylene while utilizing vastly superior dielectric properties of silicon carbide layer to create a much longer lasting and more electrically stable biomedical implants. This layer encapsulation scheme may be seamlessly incorporated into our existing fabrication process flow for our flagship product, the UEA. This encapsulation will work on different surfaces (metal, semiconductor, polymer, ceramic) and on devices with integrated wireless components making it ideal for coating any complex medical device intended for long term implant. Our preliminary results with silicon carbide coated UEA are very promising in support of the proposed work. We have shown that silicon carbide yields more stable leakage current, and stable impedance (with <5% change). This superior performance of suggests its potential usefulness for chronic implants with complex surface geometries.