Hsu Jui-Mei, Rieth Loren, Normann Richard A, Tathireddy Prashant, Solzbacher Florian
Department ofMaterials Science and Engineering, University of Utah, Salt Lake City, UT 84112, USA.
IEEE Trans Biomed Eng. 2009 Jan;56(1):23-9. doi: 10.1109/TBME.2008.2002155.
Electronic neural interfaces have been developed to restore function to the nervous system for patients with neural disorders. A conformal and chronically stable dielectric encapsulation is required to protect the neural interface device from the harsh physiological environment and localize the active electrode tips. Chemical vapor deposited Parylene-C films were studied as a potential implantable dielectric encapsulation material using impedance spectroscopy and leakage current measurements. Both tests were performed in 37 degrees C saline solution, and showed that the films provided an electrically insulating encapsulation for more than one year. Isotropic and anisotropic oxygen plasma etching processes were compared for removing the Parylene-C insulation to expose the active electrode tips. Also, the relationship between tip exposure and electrode impedance was determined. The conformity and the uniformity of the Parylene-C coating were assessed using optical microscopy, and small thickness variations on the complex 3-D electrode arrays were observed. Parylene C was found to provide encapsulation and electrical insulation required for such neural interface devices for more than one year. Also, oxygen plasma etching was found to be an effective method to etch and pattern Parylene-C films.
电子神经接口已被开发用于为患有神经障碍的患者恢复神经系统功能。需要一种保形且长期稳定的介电封装来保护神经接口设备免受恶劣的生理环境影响，并定位有源电极尖端。使用阻抗谱和漏电流测量方法，对化学气相沉积的聚对二甲苯-C薄膜作为潜在的可植入介电封装材料进行了研究。这两项测试均在37摄氏度的盐溶液中进行，结果表明这些薄膜提供了超过一年的电绝缘封装。比较了各向同性和各向异性氧等离子体蚀刻工艺以去除聚对二甲苯-C绝缘层，从而暴露有源电极尖端。此外，还确定了尖端暴露与电极阻抗之间的关系。使用光学显微镜评估了聚对二甲苯-C涂层的保形性和均匀性，并观察到复杂三维电极阵列上存在小的厚度变化。发现聚对二甲苯-C可为此类神经接口设备提供超过一年所需的封装和电绝缘。此外，发现氧等离子体蚀刻是蚀刻和图案化聚对二甲苯-C薄膜的有效方法。
