物理化学学报2020，Vol.36Issue(12)：5-11,7.DOI:10.3866/PKU.WHXB201909035
用于长期神经电生理记录的自伸展电极阵列
Self-spreadable Octopus-like Electrode Arrays for Long-term Neural Recordings
摘要
Abstract
Neural electrodes have been extensively utilized for the investigation of neural functions and the understanding of neuronal circuits because of their high spatial and temporal resolution.However,long-term effective electrophysiological recordings in free-behaving animals still constitute a challenging task,which hinders longitudinal studies on complex brain-processing mechanisms at a functionallevel.Herein,we demonstrate the feasibility and advantages of using a self-spreadable octopus-like electrode(octrode)array for long-term recordings.The octrode array was fabricated by enwrapping a bundle of eight formvar-coated nickel-chromium microwires with a layer of polyethylene glycol in a custom-made mold.After the electrodeposition of platinum nanoparticles,the microwires at the electrode tip were gathered together and then re-enwrapped with a thin layer of gelatin to maintain their structure and mechanical strength for implantation.Shortly after implantation(within 20 min),the biocompatible gelatin encapsulation swelled and dissolved,causing the self-spreading of the recording channels of the octrode array in the brain.The electrochemical characteristics of the electrode/neural tissue interface were investigated by electrochemical impedance spectroscopy(EIS).Four weeks after implantation,the average impedance of the octrodes(1.26 MΩ at 1 kHz)was significantly lower than that of the conventional tetrodes(1.50 MΩ at 1 kHz,p ＜ 0.05,t-test).Additionally,the octrodes exhibited a better pseudo-capacitive characteristic and a considerably faster ion transfer rate at the electrode interface than the tetrodes.Spontaneous action potentials and local field potentials(LFPs)were also recorded in vivo to investigate the electrophysiological performance of the octrodes.The peak-to-peak spike amplitudes recorded for the octrodes were remarkably larger than those recorded for the tetrodes.The signal quality remained at approximately the same level for the four-week period,while the peak-to-peak spike amplitudes recorded for the tetrodes decreased abruptly.Moreover,the voltage amplitudes recorded by the octrodes at 1-200 Hz were notably larger than those by the tetrodes,suggesting a higher sensitivity in the recording of electrophysiological events.Furthermore,we performed immunochemical analyses on the brain tissues at post-implantation to evaluate the histocompatibility of the electrodes.Tissue responses of the octrodes were alleviated considerably,evidenced by the reduced astroglial intensity and increased neuron density around the implant site as compared to the tetrodes,which may be due to the relatively small size of each decentralized recording channel after self-spreading in vivo.Generally,the fabricated octrodes exhibited a lower electrochemical impedance value at the octrode/neural tissue interface and an increased signal quality during the long-term electrophysiological recording in freely moving mice as compared to the conventional tetrodes.All of these are desirable characteristics in neural circuit dissections in vivo.关键词
神经电极/神经界面/电极阻抗/组织反应/电生理记录Key words
Neural electrode/Neural interface/Electrode impedance/Tissue response/Electrophysiological recording分类
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王璐璐,谢泽鑫,钟成,唐永强,叶丰明,王立平,鲁艺..用于长期神经电生理记录的自伸展电极阵列[J].物理化学学报,2020,36(12):5-11,7.基金项目
The project was supported by the National Natural Science Foundation of China(31871080 and 31700921),the Strategic Priority Research Program of the CAS(XDBS01030100),the Youth Innovation Promotion Association of the CAS,the Science and Technology Planning Project of Guangdong Province(2018B030331001),the Natural Science Foundation of Guangdong Province(2016A030313182),and the Guangdong Key Lab of Brain Connectome(2017B030301017).国家自然科学基金(31871080,31700921),中科院战略先导专项(XDBS01030100),中科院青年创新促进会,广东省科技专项(2018B030331001),广东省自然科学基金(2016A030313182),广东省脑连接图谱重点实验室(2017B030301017)资助项目 （31871080 and 31700921）
