Universidade do Algarve, Faculdade de Ciências e Tecnologia, 8005-139, Faro, Portugal.
Instituto de Telecomunicações, Avenida Rovisco Pais 1, 1049-001, Lisboa, Portugal.
Sci Rep. 2017 Oct 27;7(1):14284. doi: 10.1038/s41598-017-14697-y.
Ultra-sensitive electrodes for extracellular recordings were fabricated and electrically characterized. A signal detection limit defined by a noise level of 0.3-0.4 μV for a bandwidth of 12.5 Hz was achieved. To obtain this high sensitivity, large area (4 mm) electrodes were used. The electrode surface is also micro-structured with an array of gold mushroom-like shapes to further enhance the active area. In comparison with a flat gold surface, the micro-structured surface increases the capacitance of the electrode/electrolyte interface by 54%. The electrode low impedance and low noise enable the detection of weak and low frequency quasi-periodic signals produced by astrocytes populations that thus far had remained inaccessible using conventional extracellular electrodes. Signals with 5 μV in amplitude and lasting for 5-10 s were measured, with a peak-to-peak signal-to-noise ratio of 16. The electrodes and the methodology developed here can be used as an ultrasensitive electrophysiological tool to reveal the synchronization dynamics of ultra-slow ionic signalling between non-electrogenic cells.
我们制作并电特性分析了超灵敏的用于细胞外记录的电极。我们实现了一个信号检测极限，其噪声水平为 0.3-0.4 μV，带宽为 12.5 Hz。为了获得这种高灵敏度，我们使用了大面积（4 毫米）的电极。电极表面还采用了金蘑菇状结构的微结构，以进一步增加有效面积。与平面金表面相比，微结构表面将电极/电解质界面的电容增加了 54%。电极的低阻抗和低噪声使得能够检测到由星形胶质细胞群体产生的微弱和低频准周期性信号，而使用传统的细胞外电极则无法检测到这些信号。我们测量到了幅度为 5 μV 且持续 5-10 s 的信号，其峰峰值信噪比为 16。这里开发的电极和方法可以用作超灵敏的电生理学工具，以揭示非发电细胞之间超慢离子信号的同步动力学。
