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采用箔和线电极连接到密封钛罐中的植入式脉冲发生器（IPG）。每个电极通过组装到柔性导线中的绝缘多股导线单独连接到IPG。这种结构通过限制可以在假体中使用的电极的数量和尺寸来限制治疗选择。我们的目标是开发基于聚合物的多电极阵列，克服这些限制。该阵列是聚酰亚胺基的，具有适合于氧化铱和其他低阻抗、高电荷容量涂层的电极位点。这些创新是：1）使用薄膜无机介电封装和粘合层，提供类似密封的阻隔性能; 2）非密封封装，采用表面官能化的有机硅和硅基密封剂的薄膜。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。共价键合到薄膜无机填料上的有机硅填料的组合预期将在患者的生命中保护阵列上的有源电路和电互连。相对于先前的薄膜方法和现有的临床多电极导线和IPG，所提出的技术的优势包括：1）非密封封装，为阵列上的金属化、ASIC和互连提供长期保护; 2）植入式电子封装，体积小且灵活，允许将器械放置在手术困难且刚性IPG耐受性差的位置。第一阶段的目标是证明采用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将接受加速体外试验，以确定器械的耐久性，并为II期慢性动物试验中的阵列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有机硅澄清剂的非密封封装;目标2。旨在证明聚酰亚胺阵列上16通道刺激ASIC的封装，并对组件进行刺激脉冲测试和加速体外测试。该项目是EIC实验室（诺伍德，MA）和Sigenics Inc.（伊利诺伊州芝加哥）。在第一阶段，EIC将进行阵列制造和测试，而Sigenics Inc.将提供ASIC、引线键合和测试聚合物封装的专业知识。 公共卫生相关性：柔性聚合物封装的多电极阵列和植入式电子器件的发展将允许开发具有比现有技术可能的电极数量大得多的电极的神经假体。由用聚合物封装代替钛罐而产生的电子封装的小尺寸将允许在身体中的部位处外科手术放置装置，这对于常规装置是不可能的。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病症的患者受益。

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.