Ji Bowen, Guo Zhejun, Wang Minghao, Yang Bin, Wang Xiaolin, Li Wen, Liu Jingquan
1National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Department of Micro/Nano Electronics, Shanghai Jiao Tong University, Shanghai, 200240 China.
2Electrical and Computer Engineering Department, Michigan State University, East Lansing, MI 48824 USA.
Microsyst Nanoeng. 2018 Oct 8;4:27. doi: 10.1038/s41378-018-0027-0. eCollection 2018.
In this paper, a polyimide-based flexible device that integrates 16 micro-LEDs and 16 IrO -modified microelectrodes for synchronous photostimulation and neural signal recording is presented. The 4 × 4 micro-LEDs (dimensions of 220 × 270 × 50 μm, 700 μm pitch) are fixed in the SU-8 fence structure on a polyimide substrate and connected to the leads via a wire-bonding method. The recording electrodes share a similar fabrication process on the polyimide with 16 microelectrode sites (200 μm in diameter and 700 μm in pitch) modified by iridium oxide (IrO ). These two subparts can be aligned with alignment holes and glued back-to-back by epoxy, which ensures that the light from the LEDs passes through the corresponding holes that are evenly distributed around the recording sites. The long-term electrical and optical stabilities of the device are verified using a soaking test for 3 months, and the thermal property is specifically studied with different duty cycles, voltages, and frequencies. Additionally, the electrochemical results prove the reliability of the IrO -modified microelectrodes after repeated pressing or friction. To evaluate the tradeoff between flexibility and strength, two microelectrode arrays with thicknesses of 5 and 10 μm are evaluated through simulation and experiment. The proposed device can be a useful mapping optogenetics tool for neuroscience studies in small (rats and mice) and large animal subjects and ultimately in nonhuman primates.
本文介绍了一种基于聚酰亚胺的柔性器件，该器件集成了16个微发光二极管（micro-LED）和16个氧化铱修饰的微电极，用于同步光刺激和神经信号记录。4×4的微发光二极管（尺寸为220×270×50μm，间距700μm）固定在聚酰亚胺基板上的SU-8围栏结构中，并通过引线键合方法连接到引线。记录电极在聚酰亚胺上采用类似的制造工艺，有16个微电极位点（直径200μm，间距700μm）用氧化铱（IrO）修饰。这两个子部分可通过对准孔对准，并通过环氧树脂背对背粘合，这确保了来自发光二极管的光穿过均匀分布在记录位点周围的相应孔。通过3个月的浸泡测试验证了该器件的长期电学和光学稳定性，并针对不同的占空比、电压和频率对其热性能进行了专门研究。此外，电化学结果证明了氧化铱修饰的微电极在反复按压或摩擦后的可靠性。为了评估柔韧性和强度之间的权衡，通过模拟和实验对厚度为5μm和10μm的两种微电极阵列进行了评估。所提出的器件可以成为一种有用的光遗传学映射工具，用于小型（大鼠和小鼠）和大型动物受试者以及最终在非人类灵长类动物中的神经科学研究。
