Separation of macromolecules by one-dimensional or two-dimensional methods, such as
gel electrophoresis, produces an array of macromolecules, which can be transferred to a support, thereby producing the same array as on the gel. In the case of one-dimensional
gel electrophoresis, because of the regular spacing of the gel lanes and the predictable direction of migration of the macromolecules, the positions of the
macromolecule spots or bands in the array can be predicted to be at least within the area of the support corresponding to the lanes of the gel. Where the molecular weight of a
macromolecule of interest is known, molecular weight markers can be used to determine where the
macromolecule band is on the support, even if the macromolecule is not stained in the gel or on the support. Assays that reveal characteristics of the macromolecule can be carried out by spotting reagents onto the support in a series of microspots of small volume in a line which intersects the macromolecule band, and which corresponds to the line of the direction of migration of the macromolecules on the gel. Appropriate detection methods can be applied, depending on the
reagent, to see the results. The steps for locating the bands of macromolecules, applying reagents, and detecting the effect of the
reagent on the macromolecule can be automated in an appropriate instrument.