Multi-electrode Arrays with Non-hermetic Encapsulation for Neural Prostheses

描述(由申请人提供)：目前商业使用的神经假体使用箔和线电极，连接到密封钛罐中的植入式脉冲发生器(IPG)。每个电极通过组装成柔性导线的绝缘多股导线单独连接到IPG。这种结构通过限制可用于假体的电极的数量和大小来限制治疗选择。我们的目标是开发基于聚合物的多电极阵列，以克服这些限制。该阵列是以聚酰亚胺为基础的，其电极位置适合于氧化铱和其他低阻抗、高充电容量涂层。使创新成为可能的是1)使用可提供密封性的薄膜无机电介质封装和粘合层，以及2)采用表面功能化介电材料和有机硅密封剂薄膜的非密封性封装。这种非密封封装将允许将专用集成电路(ASIC)直接放置在阵列上，并将取代用于容纳电池、脉冲发生器和通信电路的传统钛或陶瓷外壳。有机硅密封剂与薄膜无机介电材料共价结合，有望在患者的生命周期内保护阵列上的有源电路和电气互连。与以前的薄膜方法和现有的临床多电极引线和IPG相比，建议的技术的优势包括：1)非密封性封装，可为阵列上的金属化、ASIC和互连提供长期保护；以及2)植入式电子封装，其体积小且灵活，允许将设备放置在手术困难且对刚性IPG耐受性较差的位置。第一阶段的目标是演示使用16通道ASIC刺激器的非密封封装多电极阵列的制造和功能。这些阵列和ASIC将接受加速体外测试，以确定器件的耐用性，并为第二阶段慢性动物试验的阵列的长期稳定性提供信心。第一阶段的目标如下：目标1.开发和测试基于表面功能化无机涂层和硅胶密封剂的非密封性封装；目的2.演示16通道刺激ASIC在聚酰亚胺阵列上的封装，并进行刺激脉冲测试和组件的加速体外测试。该项目是EIC实验室(位于马萨诸塞州诺伍德)和Sigics Inc.(位于伊利诺伊州芝加哥)之间的合作项目。在第一阶段，EIC将进行阵列制造和测试，而Sigurics Inc.将提供ASIC、引线键合和测试基于聚合物的封装的专业知识。 与公共卫生相关：柔性聚合物封装的多电极阵列和植入电子设备的开发将使神经假体的开发具有比目前技术所可能的更多的电极数量。由于用聚合物封装取代钛罐而产生的电子封装尺寸较小，这将允许在人体内的位置进行外科手术放置设备，否则使用传统设备是不可能的。这些阵列将使患有脊髓损伤、中风、失明和其他需要电刺激治疗的疾病或障碍的患者受益。

DESCRIPTION (provided by applicant): Neural prostheses presently in commercial use employ foil and wire electrodes connected to implantable pulse generators (IPGs) housed in hermetically sealed titanium cans. Each electrode is individually connected to the IPG by insulated multistrand wire assembled into a flexible lead. This construction constrains treatment options by limiting the number and size of the electrodes that can be used in a prosthesis. Our objective is the development of polymer-based multielectrode arrays that overcome these limitations. The arrays are polyimide-based with electrode sites suitable for iridium oxide and other low-impedance, high charge capacity coatings. The enabling innovations are 1) the use of a thin-film inorganic dielectric encapsulation and adhesion layer that provides hermetic-like barrier properties and 2) a non-hermetic encapsulation that employs thin films of surface-functionalized dielectrics and silicone-based sealants. The non-hermetic encapsulation will allow placement of application specific integrated circuits (ASICs) directly on the arrays and will replace the traditional titanium or ceramic case used to house batteries, pulse generators, and communications circuitry. The combination of silicone encapsulants covalently bonded to thin-film inorganic dielectrics is expected to protect active circuitry and electrical interconnects on the arrays for the life of the patient. The advantages of the proposed technology, relative to previous thin-film approaches and existing clinical multielectrode leads and IPGs include: 1) a non-hermetic encapsulation that provides chronic protection of metallization, ASICs, and interconnects on the arrays; and 2) an implanted electronic package that is small and flexible allowing placement of the device in locations that would be surgical difficult and poorly tolerant of rigid IPGs. The Phase I objective is to demonstrate the fabrication and functioning of non-hermetically encapsulated multielectrode arrays employing a 16-channel ASIC stimulator. These arrays and ASICs would be subjected to accelerated in vitro testing to establish the durability of the devices and to provide confidence in the long-term stability of the arrays for chronic animal testing in Phase II. The Phase I Aims are as follows: Aim 1. To develop and test non-hermetic encapsulation based on surface functionalized inorganic coatings and silicone encapsulants; Aim 2. To demonstrate the encapsulation of a 16-channel stimulation ASIC on a polyimide array and to conduct stimulation pulse testing and accelerated in vitro testing of the assembly. The program is a collaboration between EIC Laboratories (Norwood, MA) and Sigenics Inc. (Chicago, Ill). In Phase I, EIC will conduct the array fabrication and testing while Sigenics Inc. will provide ASICs, wire bonding, and expertise in testing polymer-based encapsulation. PUBLIC HEALTH RELEVANCE: The development of flexible polymer encapsulated multielectrode arrays and implanted electronics will allow the development of neural prostheses with a significantly greater number of electrodes than is possible with present technology. The small size of the electronic package resulting from replacement of titanium cans with polymer encapsulation will allow surgical placement of devices at sites in the body that would not be otherwise possible with conventional devices. These arrays will benefit patients with spinal cord injury, stroke, blindness and other diseases or disorders requiring electrical stimulation for treatment.