Nanoenabled Direct Contact Interfacing of Syringe-Injectable Mesh Electronics
Nanoenabled Direct Contact Interfacing of Syringe-Injectable Mesh Electronics
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DOI：
10.1021/acs.nanolett.9b03019
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发表时间：
2019-08-01
期刊：
影响因子：
10.8
通讯作者：
Lieber, Charles M.
中科院分区：
文献类型：
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作者：
Lee, Jung Min;Hong, Guosong;Lieber, Charles M.
聚合物基电子器件具有低弯曲刚度和高灵活性，包括最近报道的大孔注射器可注射网状电子器件，在活体动物大脑神经回路的慢性研究中显示出巨大的前景。利用这些高柔性材料进行体内研究的核心挑战集中在开发高效的输入/输出（I/O）连接到具有高产量、低键合阻力和长期稳定性的外部接口上。在这里，我们报告了一种应用于具有挑战性的可注射网状电子产品的新范例，该范例利用纳米级厚度的双面金属I/O垫的高灵活性，可以变形并接触标准接口电缆，并具有长期的电气稳定性。首先，我们描述了双面金属I/O衬垫的设计和简易制造，允许不考虑探针方向的接触。其次，系统研究了接触电阻与I/O焊盘设计和机械性能的关系，证明了I/O焊盘弯曲刚度在实现低电阻稳定接触方面的关键作用。此外，计算研究提供了在角度不对准的情况下实现高产量多路接触接口的设计规则，从而使相邻通道不短路。第三，使用直接接触方法对连接到接口电缆上的32通道网状电子探针进行体外测量，显示出可重复的高电连接收率。最后，在活体小鼠体内植入32通道网状电子探针的实验证明了直接接触界面的长期稳定性，可以在至少2个月内持续跟踪单个神经活动而不会丢失通道记录。直接接触接口方法为用于神经记录和调制的多路网状电子神经探针的可扩展长期连接铺平了道路，而且可用于促进生物研究和治疗应用中其他柔性电子的可扩展互连。
Polymer-based electronics with low bending stiffnesses and high flexibility, including recently reported macroporous syringe-injectable mesh electronics, have shown substantial promise for chronic studies of neural circuitry in the brains of live animals. A central challenge for exploiting these highly flexible materials for in vivo studies has centered on the development of efficient input/output (I/O) connections to an external interface with high yield, low bonding resistance, and long-term stability. Here we report a new paradigm applied to the challenging case of injectable mesh electronics that exploits the high flexibility of nanoscale thickness two-sided metal I/O pads that can deform and contact standard interface cables in high yield with long-term electrical stability. First, we describe the design and facile fabrication of two-sided metal I/O pads that allow for contact without regard to probe orientation. Second, systematic studies of the contact resistance as a function of I/O pad design and mechanical properties demonstrate the key role of the I/O pad bending stiffness in achieving low-resistance stable contacts. Additionally, computational studies provide design rules for achieving high-yield multiplexed contact interfacing in the case of angular misalignment such that adjacent channels are not shorted. Third, the in vitro measurement of 32-channel mesh electronics probes bonded to interface cables using the direct contact method shows a reproducibly high yield of electrical connectivity. Finally, in vivo experiments with 32-channel mesh electronics probes implanted in live mice demonstrate the chronic stability of the direct contact interface, enabling consistent tracking of single unit neural activity over at least 2 months without a loss of channel recording. The direct contact interfacing methodology paves the way for scalable long-term connections of multiplexed mesh electronics neural probes for neural recording and modulation and moreover could be used to facilitate a scalable interconnection of other flexible electronics in biological studies and therapeutic applications.