Wu Ren-Guei, Yang Chung-Shi, Lian Cheng-Kuang, Cheing Ching-Chang, Tseng Fan-Gang
Department of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan.
Electrophoresis. 2009 Jul;30(14):2523-31. doi: 10.1002/elps.200800809.
In this research, a technique incorporating dual-asymmetry electrokinetic flow (DAEKF) was applied to a nanoCE electrochemical device for the pre-concentration and detection of catecholamines. The DAEKF was constructed by first generating a zeta-potential difference between the top and bottom walls, which had been pre-treated with O2 and H2O surface plasma, respectively, yielding a 2-D gradient shear flow across the channel depth. The shear flow was then exposed to a varying zeta-potential along the downstream direction by control of the field-effect in order to cause downward rotational flow in the channel. By this mechanism, almost all of the samples were effectively brought down to the electrode surface for analysis. Simulations were carried out to reveal the mechanism of concentration caused by the DAEKF, and the results reasonably describe our experiment findings. This DAEKF technique was applied to a glass/glass CE electrochemical nanochip for the analysis of catecholamines. The optimum detection limit was determined to be 1.25 and 3.3 nM of dopamine and catechol, respectively. A detection limit at the zeptomole level for dopamine can be obtained in this device, which is close to the level released by a single neuron cell in vitro.
在本研究中，一种结合双不对称电动流（DAEKF）的技术被应用于纳米毛细管电泳电化学装置，用于儿茶酚胺的预浓缩和检测。DAEKF的构建方法是，首先分别对顶壁和底壁进行O₂和H₂O表面等离子体预处理，在两者之间产生zeta电位差，从而在通道深度上产生二维梯度剪切流。然后通过控制场效应，使剪切流沿下游方向暴露于变化的zeta电位，从而在通道中引起向下的旋转流。通过这种机制，几乎所有样品都能有效地被带到电极表面进行分析。进行了模拟以揭示DAEKF引起的浓缩机制，结果合理地描述了我们的实验发现。这种DAEKF技术被应用于玻璃/玻璃毛细管电泳电化学纳米芯片，用于分析儿茶酚胺。确定多巴胺和儿茶酚的最佳检测限分别为1.25 nM和3.3 nM。在该装置中可获得zeptomole水平的多巴胺检测限，这接近单个神经元细胞在体外释放的水平。
