Schulte A, Chow R H
Department of Molecular Biology of Neuronal Signaling, Max Planck Institute for Experimental Medicine, Hermann Rein Strasse 3, 37075 Goettingen, Germany, and Department of Physiology, University of Edinburgh Medical School, Teviot Place, Edinburgh EH8 9AG, Scotland.
Anal Chem. 1998 Mar 1;70(5):985-90. doi: 10.1021/ac970934e.
The most important sources of noise with disk-shaped carbon-fiber microelectrodes (CFMEs) are the exposed cut disk face of the fiber itself and the seal region between the carbon fiber and the applied insulating layer. To reduce noise and to fabricate simple, reproducible low-noise CFMEs, we sealed commercially available carbon fibers in pulled glass pipets and then we performed cylindrical etching of the fiber extending beyond the glass sheath, followed by insulation with anodic electrophoretic deposition of paint. The resulting CFMEs had electroactive carbon disks with radii as small as ∼0.5 μm. The noise of such electrodes was minimized by virtue of a design that ensures a good seal between the carbon fiber and its insulation and a reduced diameter of the exposed carbon. In contrast to CFMEs made of conically etched carbon fibers, cylindrically etched CFMEs offer the significant advantage that they can be easily reused: The cylindrically etched region extends over several hundreds of micrometers and, therefore, can be cut back repeatedly to expose a fresh carbon surface of uniform diameter. The low noise and small size of these electrodes make them ideal for the high-sensitivity measurements demanded in studies of single-vesicle transmitter release from secretory cells. Furthermore, the small cross-sectional diameter of the tips allows them to be used in restricted spaces, such as inside the tapering micrometer-diameter tips of melted and pulled glass microcapillaries (e.g., patch pipets).
对于盘状碳纤维微电极（CFME）而言，最重要的噪声源是纤维本身暴露的切割盘面以及碳纤维与所施加绝缘层之间的密封区域。为了降低噪声并制造简单、可重复的低噪声CFME，我们将市售碳纤维密封在拉制的玻璃吸管中，然后对伸出玻璃鞘的纤维进行圆柱形蚀刻，接着通过阳极电泳沉积涂料进行绝缘处理。所得的CFME具有半径小至约0.5μm的电活性碳盘。这种电极的噪声通过一种设计得以最小化，该设计确保了碳纤维与其绝缘层之间的良好密封以及减小了暴露碳的直径。与由锥形蚀刻碳纤维制成的CFME不同，圆柱形蚀刻的CFME具有显著优势，即它们可以轻松重复使用：圆柱形蚀刻区域延伸超过数百微米，因此可以反复切割以露出直径均匀的新鲜碳表面。这些电极的低噪声和小尺寸使其成为研究分泌细胞单囊泡递质释放所需高灵敏度测量的理想选择。此外，尖端的小横截面直径使它们能够用于受限空间，例如在熔化和拉制的玻璃微毛细管（如膜片吸管）逐渐变细的微米级直径尖端内部。
