title: Scanning electrochemical microscopy as a readout tool for protein electrophoresis.
abstract: 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.
authors.affiliation: Laboratoire d'Electrochimie Physique et Analytique, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Meiqin
authors.initials: M
authors.lastname: Zhang
authors.forename: Gunther
authors.initials: G
authors.lastname: Wittstock
authors.forename: Yuanhua
authors.initials: Y
authors.lastname: Shao
authors.forename: Hubert H
authors.initials: HH
authors.lastname: Girault
mesh_terms: D004563:Electrochemistry; D004586:Electrophoresis / Q000379:methods; D007782:Lactoglobulins / Q000032:analysis; D013058:Mass Spectrometry / Q000379:methods; D008855:Microscopy, Electron, Scanning / Q000379:methods*; D009211:Myoglobin / Q000032:analysis; D036103:Nanotechnology / Q000379:methods*; D010084:Oxidation-Reduction; D011145:Polyvinyls / Q000737:chemistry*; D011506:Proteins / Q000032:analysis*; D012680:Sensitivity and Specificity; D012709:Serum Albumin / Q000032:analysis; D012834:Silver / Q000737:chemistry*; D013194:Staining and Labeling; D005465:Fluorocarbon Polymers
chemical_list: D007782:Lactoglobulins; D009211:Myoglobin; D011145:Polyvinyls; D011506:Proteins; D012709:Serum Albumin; D012834:Silver; C024865:polyvinylidene fluoride; D005465:Fluorocarbon Polymers