Liu Yingzi, Li Meina, Zhang Fan, Zhu Anwei, Shi Guoyue
School of Chemistry and Molecular Engineering, East China Normal University, 500 Dongchuan Road, Shanghai 200241, P.R. China.
Anal Chem. 2015 Jun 2;87(11):5531-8. doi: 10.1021/ac5042999. Epub 2015 May 15.
A Au disk nanoelectrode down to 3 nm in radius was developed by a facile and reliable method and successfully applied for monitoring dopamine release from single living vesicles. A fine etched Au wire was coated with cathodic electrophoretic paint followed by polyimide, which retracted from the tip end during curing to expose the Au nanotip. By cyclic voltammetric scanning the above tip in 0.5 M KCl, the transformation of a core-shaped apex into a geometrically well-defined Au disk nanoelectrode with different dimensions can be controllably and reproducibly achieved. Scanning electron microscopy, transmission electron microscopy, and steady-state voltammetry were used to determine the size of nanoelectrodes. The results showed that the specific etching and insulation method not only avoids the use of toxic etching solution and the uncontrollable treatment to expose the tip but also makes possible the controllable and reproducible fabrication of Au disk nanoelectrode down to 3 nm in radius. The nanoelectrodes with well-demonstrated analytical performance were further applied for amperometrically monitoring dopamine release from single rat pheochromacytoma cells with high spatial resolution.
通过一种简便可靠的方法制备了半径低至3 nm的金盘纳米电极，并成功应用于监测单个活囊泡中多巴胺的释放。将一根精细蚀刻的金线涂上阴极电泳漆，然后再涂上聚酰亚胺，聚酰亚胺在固化过程中从尖端缩回，从而暴露出金纳米尖端。通过在0.5 M KCl中对上述尖端进行循环伏安扫描，可以可控且可重复地实现将核形尖端转变为具有不同尺寸的几何形状明确的金盘纳米电极。使用扫描电子显微镜、透射电子显微镜和稳态伏安法来确定纳米电极的尺寸。结果表明，这种特定的蚀刻和绝缘方法不仅避免了使用有毒蚀刻溶液以及暴露尖端的不可控处理，而且使得可控且可重复地制备半径低至3 nm的金盘纳米电极成为可能。具有良好分析性能的纳米电极进一步用于以高空间分辨率安培法监测单个大鼠嗜铬细胞瘤细胞中多巴胺的释放。
