Research Group for Implantable Microsystems, Faculty of Information Technology and Bionics, Pázmány Péter Catholic Uiversity, Budapest, Hungary. Doctoral School of Chemical Engineering and Material Sciences, Pannon University, Veszprém, Hungary. Insitute for Technical Physics and Material Science, Centre for Energy Research, Hungarian Academy of Sciences, Budapest, Hungary.
J Neural Eng. 2018 Oct;15(5):054003. doi: 10.1088/1741-2552/aacf71. Epub 2018 Jun 27.
Intracranial EEG (iEEG) or micro-electrocorticography (µECoG) microelectrodes offer high spatial resolution in recordings of neuronal activity from the exposed brain surface. Reliability of dielectric substrates and conductive materials of these devices are under intensive research in terms of functional stability in biological environments.
The aim of our study is to investigate the stability of electroplated platinum recording sites on 16-channel, 8 micron thick, polyimide based, flexible µECoG arrays implanted underneath the skull of rats. Scanning electron microscopy and electrochemical impedance spectroscopy was used to reveal changes in either surface morphology or interfacial characteristics. The effect of improved surface area (roughness factor = 23 ± 0.12) on in vivo recording capability was characterized in both acute and chronic experiments.
Besides the expected reduction in thermal noise and enhancement in signal-to-noise ratio (up to 39.8), a slight increase in the electrical impedance of individual sites was observed, as a result of changes in the measured interfacial capacitance. In this paper, we also present technology processes and protocols in detail to use such implants without crack formation of the porous platinum surfaces.
Our findings imply that black-platinum coating deposited on the recording sites of flexible microelectrodes (20 microns in diameter) provides a stable interface between tissue and device.
颅内脑电图（iEEG）或微脑电描记术（µECoG）微电极在记录暴露于大脑表面的神经元活动方面提供了高空间分辨率。这些设备的介电基底和导电材料的功能稳定性在生物环境中受到广泛研究。
我们的研究目的是研究在大鼠颅骨下植入的 16 通道、8 微米厚、聚酰亚胺基、柔性µECoG 阵列上的电镀铂记录位点的稳定性。扫描电子显微镜和电化学阻抗谱用于揭示表面形貌或界面特性的变化。在急性和慢性实验中，我们还研究了改进的表面积（粗糙度因子=23±0.12）对体内记录能力的影响。
除了预期的热噪声降低和信噪比增强（高达 39.8）外，还观察到单个位点的电导率略有增加，这是由于测量的界面电容发生变化所致。在本文中，我们还详细介绍了使用这种无多孔铂表面裂纹形成的植入物的技术过程和协议。
我们的发现表明，沉积在柔性微电极（直径 20 微米）记录位点上的黑铂涂层在组织和器件之间提供了稳定的界面。
