Department of Electrical and Electric Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, 441-8580 Toyohashi, Japan.
National Institute of Technology, Ibaraki College, 866 Nakane, 312-8508 Hitachinaka, Japan.
Proc Natl Acad Sci U S A. 2021 Apr 20;118(16). doi: 10.1073/pnas.2008233118.
Microscale needle-electrode devices offer neuronal signal recording capability in brain tissue; however, using needles of smaller geometry to minimize tissue damage causes degradation of electrical properties, including high electrical impedance and low signal-to-noise ratio (SNR) recording. We overcome these limitations using a device assembly technique that uses a single needle-topped amplifier package, called STACK, within a device of ∼1 × 1 mm Based on silicon (Si) growth technology, a <3-µm-tip-diameter, 400-µm-length needle electrode was fabricated on a Si block as the module. The high electrical impedance characteristics of the needle electrode were improved by stacking it on the other module of the amplifier. The STACK device exhibited a voltage gain of >0.98 (-0.175 dB), enabling recording of the local field potential and action potentials from the mouse brain in vivo with an improved SNR of 6.2. Additionally, the device allowed us to use a Bluetooth module to demonstrate wireless recording of these neuronal signals; the chronic experiment was also conducted using STACK-implanted mice.
微尺度针状电极设备可在脑组织中实现神经元信号记录功能；然而，使用更小几何形状的针来最小化组织损伤会导致电性能下降，包括高电阻和低信噪比 (SNR) 记录。我们使用一种器件组装技术克服了这些限制，该技术使用单个针顶放大器封装，称为 STACK，位于约 1×1 毫米的器件内。基于硅 (Si) 生长技术，在 Si 块上制造了一个尖端直径为 <3-µm、长度为 400-µm 的针状电极作为模块。通过将针状电极堆叠在放大器的另一个模块上，提高了其高电阻特性。STACK 器件的电压增益>0.98（-0.175 dB），能够记录体内小鼠大脑的局部场电位和动作电位，并提高 SNR 至 6.2。此外，该器件还允许我们使用蓝牙模块来演示这些神经元信号的无线记录；使用植入了 STACK 的小鼠进行了慢性实验。
