In-vivo implant mechanics of flexible, silicon-based ACREO microelectrode arrays in rat cerebral cortex
In-vivo implant mechanics of flexible, silicon-based ACREO microelectrode arrays in rat cerebral cortex
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DOI：
10.1109/tbme.2006.872824
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发表时间：
2006-05-01
影响因子：
4.6
通讯作者：
Hofmann, UG
中科院分区：
文献类型：
--
作者：
Jensen, W;Yoshida, K;Hofmann, UG
电极植入神经组织过程中的机械行为会对组织内发生的神经连接和信号传递产生深远的影响。本工作的目的是研究VSAMUEI最近开发的柔性硅基Acreo微电极阵列的体内植入机制。财团(欧洲联盟，赠款#IST-1999-10073)。我们以前已经报道了Acreo电极的电性能[1]-[3]和机械性能[4]、[5]。本文测量了在体电极植入大鼠大脑皮质(7个急性实验，植入深度为2 mm，插入速度为2 mm/S)过程中的拉力和压缩力。我们比较了Acreo硅电极(4度张开角，1-8个轴)和单轴钨电极(3度和10度张开角)。穿透力和压痕随着横截面面积(最大和最小电极之间的统计差异)和轴数的增加而增加(没有统计学差异)。我们在回缩阶段一直观察到拉力(阻力)，这表明脑组织在很短的时间内粘在电极上。在插入电极之前用硅烷(疏水)或食人鱼(亲水)处理电极可显著降低渗透力。总而言之，我们的发现表明，用于急性动物实验的可重复使用的电极不仅必须足够强大，能够在超过穿透力的最大力中幸存下来，而且还必须能够承受回缩过程中的高张力。仔细清洁不仅可以避免异物反应，还可以减少穿透脑组织时施加在电极上的压力。
The mechanical behavior of an electrode during implantation into neural tissue can have a profound effect on the neural connections and signaling that takes place within the tissue. The objective of the present work was to investigate the in vivo implant mechanics of flexible, silicon-based ACREO microelectrode arrays recently developed by the VSAMUEI. consortium (European Union, grant #IST-1999-10073). We have previously reported on both the electrical [1]-[3] and mechanical [4], [5] properties of the ACREO electrodes. In this paper, the tensile and compression forces were measured during a series of in vivo electrode insertions into the cerebral cortex of rats (7 acute experiments, 2-mm implant depth, 2-mm/s insertion velocity). We compared the ACREO silicon electrodes (4 degrees opening angle, 1-8 shafts) to single-shaft tungsten electrodes (3 degrees and 10 degrees opening angles). The penetration force and dimpling increased with the cross-sectional area (statistical difference between the largest and the smallest electrode) and with the number of shafts (no statistical difference). We consistently observed tensile (drag) forces during the retraction phase, which indicates the brain tissue sticks to the electrode within a short time period. Treating the electrodes prior to insertion with silane (hydrophobic) or piranha (hydrophilic) significantly decreased the penetration force. In conclusion, our findings suggest that reusable electrodes for acute animal experiments must not only be strong enough to survive a maximal force that exceeded the penetration force, but must also be able to withstand high tension forces during retraction. Careful cleaning is not only important to avoid foreign body response, but can also reduce the stress applied to the electrode while penetrating the brain tissue.