Polyimide-based intracortical neural implant with improved structural stiffness
Polyimide-based intracortical neural implant with improved structural stiffness
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DOI：
10.1088/0960-1317/14/1/305
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发表时间：
2004-01-01
影响因子：
2.3
通讯作者：
Raupp, G
中科院分区：
文献类型：
--
作者：
Lee, KK;He, JP;Raupp, G
设计了一种使用聚酰亚胺生物聚合物的长期植入式皮质电极的新型结构，其提供了用于脑组织和颅骨之间以及脑/植入物界面处的微动顺应性的柔性和用于更好的手术处理的刚度。将5-10 μ m厚的硅骨架层附接到电极的尖端以增强结构刚度。然后在该刚性段之后是没有硅骨架层的Imm柔性段。所制造的植入物具有三柄，具有五个记录位点（20 μ m × 20 μ m）和每个柄上的两个40 μ m × 40 μ m的通孔。原型植入物的体外细胞毒性试验显示对细胞无不良毒性作用。评估了台架测试阻抗值，结果表明在1 KHz下的平均阻抗值类似于2 MOmega。对于5 μ m厚的硅骨架电极，聚酰亚胺基电极的刚度比没有硅骨架层的电极的刚度增加十倍。此外，具有5 μ m和10 μ m厚的硅骨架层的聚酰亚胺基电极穿透大鼠脑的软脑膜，而没有在没有硅加固的植入物中观察到的屈曲。
A novel structure for chronically implantable cortical electrodes using polyimide bio-polymer was devised, which provides both flexibility for micro-motion compliance between brain tissues and the skull and at the brain/implant interface and stiffness for better surgical handling. A 5-10 mum thick silicon backbone layer was attached to the tip of the electrode to enhance the structural stiffness. This stiff segment was then followed by a I mm flexible segment without a silicon backbone layer. The fabricated implants have tri-shanks with five recording sites (20 mum x 20 mum) and two vias of 40 mum x 40 mum on each shank. In vitro cytotoxicity tests of prototype implants revealed no adverse toxic effects on cells. Bench test impedance values were assessed, resulting in an average impedance value of similar to2 MOmega at 1 KHz. For a 5 mum thick silicon backbone electrode, the stiffness of polyimide-based electrodes was increased ten times over that of electrodes without the silicon backbone layer. Furthermore, polyimide-based electrodes with 5 mum and 10 mum thick silicon backbone layer penetrated pia of rat brain without buckling that has been observed in implants without silicon reinforcement.