Liu Junchen, Lin Sen, Li Wenzheng, Zhao Yanzhen, Liu Dingkun, He Zhaofeng, Wang Dong, Lei Ming, Hong Bo, Wu Hui
State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
State Key Laboratory of Information Photonics and Optical Communications and School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China.
Research (Wash D C). 2022 Mar 10;2022:9830457. doi: 10.34133/2022/9830457. eCollection 2022.
Noninvasive brain-computer interface (BCI) has been extensively studied from many aspects in the past decade. In order to broaden the practical applications of BCI technique, it is essential to develop electrodes for electroencephalogram (EEG) collection with advanced characteristics such as high conductivity, long-term effectiveness, and biocompatibility. In this study, we developed a silver-nanowire/PVA hydrogel/melamine sponge (AgPHMS) semidry EEG electrode for long-lasting monitoring of EEG signal. Benefiting from the water storage capacity of PVA hydrogel, the electrolyte solution can be continuously released to the scalp-electrode interface during used. The electrolyte solution can infiltrate the stratum corneum and reduce the scalp-electrode impedance to 10 k-15 k. The flexible structure enables the electrode with mechanical stability, increases the wearing comfort, and reduces the scalp-electrode gap to reduce contact impedance. As a result, a long-term BCI application based on measurements of motion-onset visual evoked potentials (mVEPs) shows that the 3-hour BCI accuracy of the new electrode (77% to 100%) is approximately the same as that of conventional electrodes supported by a conductive gel during the first hour. Furthermore, the BCI system based on the new electrode can retain low contact impedance for 10 hours on scalp, which greatly improved the ability of BCI technique.
在过去十年中，无创脑机接口（BCI）已从多个方面进行了广泛研究。为了拓宽BCI技术的实际应用，开发具有高导电性、长期有效性和生物相容性等先进特性的脑电图（EEG）采集电极至关重要。在本研究中，我们开发了一种用于长期监测EEG信号的银纳米线/聚乙烯醇水凝胶/三聚氰胺海绵（AgPHMS）半干EEG电极。受益于聚乙烯醇水凝胶的储水能力，在使用过程中电解液可不断释放至头皮-电极界面。电解液可渗透角质层，将头皮-电极阻抗降低至10 k-15 k。这种柔性结构使电极具有机械稳定性，提高了佩戴舒适度，并减小了头皮-电极间隙以降低接触阻抗。结果，基于运动起始视觉诱发电位（mVEPs）测量的长期BCI应用表明，新电极在3小时内的BCI准确率（77%至100%）与在第一小时内由导电凝胶支持的传统电极大致相同。此外，基于新电极的BCI系统在头皮上可保持10小时的低接触阻抗，这大大提高了BCI技术的能力。
