Zhang Meiqin, Wittstock Gunther, Shao Yuanhua, Girault Hubert H
Laboratoire d'Electrochimie Physique et Analytique, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
Anal Chem. 2007 Jul 1;79(13):4833-9. doi: 10.1021/ac062356k. Epub 2007 Jun 1.
Scanning electrochemical microscopy (SECM) was used to image silver-stained proteins on a poly(vinylidene difluoride) membrane. The method is based on measuring the current at a scanning microelectrode in the feedback mode. The electrochemical feedback is caused by the redox-mediated etching of the isolated 5 - 10-nm-diameter silver nanoparticles formed during the staining process. Several parameters, such as the redox mediator and the staining protocol, were optimized to ensure a high resolution and a low detection limit, i.e., 0.5 ng of bovine serum albumin (4 x 10(-14) mol) distributed on an area of 1 mm(2) (4 x 10(-16) mol x cm(-2)). Images of beta-lactoglobulin A and myoglobin bands after gel electrophoretic separation and electroblotting were obtained in order to demonstrate that SECM can be employed as a sensitive and quantitative readout method for detection of proteins after gel electrophoresis. An additional advantage is that the silver staining can be removed, allowing further downstream mass spectrometry analysis.
扫描电化学显微镜（SECM）用于对聚偏二氟乙烯膜上的银染蛋白质进行成像。该方法基于在反馈模式下测量扫描微电极处的电流。电化学反馈是由染色过程中形成的直径为5 - 10纳米的孤立银纳米颗粒的氧化还原介导蚀刻引起的。对氧化还原介质和染色方案等几个参数进行了优化，以确保高分辨率和低检测限，即分布在1平方毫米面积上的0.5纳克牛血清白蛋白（4×10⁻¹⁴摩尔）（4×10⁻¹⁶摩尔×厘米⁻²）。获得了凝胶电泳分离和电印迹后β-乳球蛋白A和肌红蛋白条带的图像，以证明SECM可作为凝胶电泳后蛋白质检测的灵敏且定量的读出方法。另一个优点是可以去除银染，从而允许进行进一步的下游质谱分析。
