3D Printed Skull Cap and Benchtop Fabricated Microwire-Based Microelectrode Array for Custom Rat Brain Recordings.

Microwire microelectrode arrays (MEAs) have been a popular low-cost tool for chronic electrophysiological recordings and are an inexpensive means to record the electrical dynamics crucial to brain function. However, both the fabrication and implantation procedures for multi-MEAs on a single rodent are time-consuming and the accuracy and quality are highly manual skill-dependent. To address the fabrication and implantation challenges for microwire MEAs, (1) a computer-aided designed and 3D printed skull cap for the pre-determined implantation locations of each MEA and (2) a benchtop fabrication approach for low-cost custom microwire MEAs were developed. A proof-of-concept design of a 32-channel 4-MEA (8-wire each) recording system was prototyped and tested through Sprague Dawley rat recordings. The skull cap design, based on the CT-scan of a single rat conforms well with multiple Sprague Dawley rats of various sizes, ages, and weight with a minimal bregma alignment error (A/P axis standard error of the mean = 0.25 mm, M/L axis standard error of the mean = 0.07 mm, n = 6). The prototyped 32-channel system was able to record the spiking activities over five months. The developed benchtop fabrication method and the 3D printed skull cap implantation platform would enable neuroscience groups to conduct in-house design, fabrication, and implantation of customizable microwire MEAs at a lower cost than the current commercial options and experience a shorter lead time for the design modifications and iterations.

微丝微电极阵列（MEAs）一直是用于慢性电生理记录的一种流行的低成本工具，并且是记录对大脑功能至关重要的电动力学的一种廉价手段。然而，在单只啮齿动物上制造和植入多个MEAs的过程既耗时，其准确性和质量又在很大程度上依赖手工技能。为了解决微丝MEAs的制造和植入难题，（1）开发了一种计算机辅助设计并3D打印的头盖骨帽，用于确定每个MEA的植入位置；（2）开发了一种用于低成本定制微丝MEAs的台式制造方法。一个32通道4 - MEA（每个8根丝）记录系统的概念验证设计被制作出原型，并通过对斯普拉格 - 道利大鼠进行记录来测试。基于单只大鼠CT扫描的头盖骨帽设计，与不同大小、年龄和体重的多只斯普拉格 - 道利大鼠都很贴合，前囟对齐误差极小（前后轴均值标准误差 = 0.25毫米，左右轴均值标准误差 = 0.07毫米，n = 6）。制作出原型的32通道系统能够在五个月内记录到尖峰活动。所开发的台式制造方法和3D打印的头盖骨帽植入平台将使神经科学研究小组能够以比当前商业选择更低的成本进行可定制微丝MEAs的内部设计、制造和植入，并在设计修改和迭代方面经历更短的交付周期。