Optimal design of nickel-coated protein chips using Taguchi approach

For the traditional ion-metal affinity chromatography, the nickel is used to capture the histidines(His)-tagged protein to make up a rapid purification system from the organism lysate. In this paper, a nickel-coated substrate was fabricated by electroplating technology in order to design a planar protein microarray chip. The Taguchi method was adopted to determine the optimal process of the nickel-coated chip using L18 orthogonal array for eight electroplating parameters, such as electroplating buffer, four kinds of electroplating additives, current density, and temperature of electroplating buffer, with three levels for each factor. Then, we utilized the immunoassay to investigate the properties of the protein chip, and the signal was detected by confocal scanner. The result shows the Ni-coated slide has better specific binding ability than nitrocellulose coated slide and the S/N ratio of the immune assay can be improved from 34.12 to 83.42 after optimizing eight electroplating parameters.