容易かつ廉価な多チャンネル柔軟神経電極の作製法の開発(<特集>生体医工学シンポジウム2008)  [in Japanese] Development of Easier and Inexpensive Method for Flexible Multichannel Neural Electrodes(<Special Contribution>Symposium on Biomedical Engineering 2008)  [in Japanese]

This paper provides an easier and inexpensive method for fabricating flexible multichannel neural electrodes based on photosensitive material by using Micro Electro Mechanical System technologies. A conventional micromachining with non-photosensitive materials such as Poly (para-xylylene) (Parylene) or non-photosen-sitive polyimide includes a dry etching process. The dry etching process requires expensive machinery and maintenance cost, and involves complex multilevel processes for controlling etching conditions to define the outline of the neural electrodes and to expose the microelectrodes for detecting neural signals. Our method applying photosensitive material eliminates these costly and complex processes. This means that more options are allowed for optimizing the configuration and size of neural electrodes depending on experimental purposes, and electrodes could be fabricated at a lower cost with improved process yields. In this study, we used photosensitive polyimide, and designed and fabricated two types of flexible neural electrodes for recording an electrocorticogram or intracortical action potentials. The fabricated neural electrodes had physical properties (such as size and impedance) that were satisfactory for neural recordings. It was confirmed that the fabricated neural electrodes permit recording neural signals successfully from the rat's cerebral cortex.