Carbon nanofiber-filled conductive silicone elastomers as soft, dry bioelectronic interfaces
Carbon nanofiber-filled conductive silicone elastomers as soft, dry bioelectronic interfaces
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DOI：
10.1371/journal.pone.0189415
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发表时间：
2018-02-06
期刊：
影响因子：
3.7
通讯作者：
Mrozek, Randy A.
中科院分区：
文献类型：
--
作者：
Slipher, Geoffrey A.;Hairston, W. David;Mrozek, Randy A.
柔软和柔韧的导电聚合物复合材料有望用作生物电子接口，例如用于脑电图（EEG）。在临床、实验室和真实世界的EEG中，需要干燥、柔软和舒适的头皮接口，其能够将μ V级头皮电位传递到信号处理电子器件。一个关键的挑战是，大多数材料的方法是敏感的变形引起的电阻抗的变化与降低的信噪比。这在存在人类运动的真实世界环境中是特别关注的。由于这一挑战，在严格控制的实验室或临床环境之外的整套大脑信息目前无法获得。在这里，我们探索了一种弹性体材料解决方案的性能，该解决方案专门设计用于EEG的干燥、柔软、舒适的头皮接触电极，该电极专门针对对变形具有平坦的电阻抗响应，以能够在真实的世界环境中使用。在三种填充率（3、4和7体积%）下评估导电碳纤维填充的聚二甲基硅氧烷（CNFPDMS）弹性体。机电测试数据显示大的压缩变形对电阻抗的影响，以及弹性体刚度上的填料加载的影响。为了评价EEG的可用性，通过接触电极重放预先记录的人类EEG信号，接触电极承受0 - 35%的准静态压缩应变。这些测试表明，导电填料比远高于电渗流阈值是理想的，以便最大化信噪比和与理想基线的信号相关性。增加填充比产生越来越平坦的电阻抗响应大施加的压缩变形与贸易增加的材料刚度，并与标称电阻抗可调超过4个数量级。EEG性能不依赖于填充物负载高于4vol%CNF（< 10（3）欧姆）。
Soft and pliable conductive polymer composites hold promise for application as bioelectronic interfaces such as for electroencephalography (EEG). In clinical, laboratory, and real-world EEG there is a desire for dry, soft, and comfortable interfaces to the scalp that are capable of relaying the mu V-level scalp potentials to signal processing electronics. A key challenge is that most material approaches are sensitive to deformation-induced shifts in electrical impedance associated with decreased signal-to-noise ratio. This is a particular concern in real-world environments where human motion is present. The entire set of brain information outside of tightly controlled laboratory or clinical settings are currently unobtainable due to this challenge. Here we explore the performance of an elastomeric material solution purposefully designed for dry, soft, comfortable scalp contact electrodes for EEG that is specifically targeted to have flat electrical impedance response to deformation to enable utilization in real world environments. A conductive carbon nanofiber filled polydimethylsiloxane (CNFPDMS) elastomer was evaluated at three fill ratios (3, 4 and 7 volume percent). Electromechanical testing data is presented showing the influence of large compressive deformations on electrical impedance as well as the impact of filler loading on the elastomer stiffness. To evaluate usability for EEG, pre-recorded human EEG signals were replayed through the contact electrodes subjected to quasi-static compressive strains between zero and 35%. These tests show that conductive filler ratios well above the electrical percolation threshold are desirable in order to maximize signal-to-noise ratio and signal correlation with an ideal baseline. Increasing fill ratios yield increasingly flat electrical impedance response to large applied compressive deformations with a trade in increased material stiffness, and with nominal electrical impedance tunable over greater than 4 orders of magnitude. EEG performance was independent of filler loading above 4 vol% CNF (< 10(3) ohms).