Layered Peptide Arrays

Figure 1 The original form of LES format works as follows. The biomolecules in a concentrated sample are distributed in portions to layered membranes, forming replicates. This is performed very simply by causing a controlled form of diffusion. This diagram indicates a two-step process. First (left), all the materials in a tissue section below the membrane stack are being distributed to all the membrane layers above (large vertical arrow). Second (horizontal arrows), the different membranes are separated, and then a different probe is applied to each one (filled symbols). Specific binding of each probe demonstrates the presence of the specific target biomolecule upon visualization. If the sample has a two dimensional physical structure, such as cellular proteins from a tissue section, the technique also maps the exact physical position of an analyte in the original sample (clear symbols). This reveals the location of the cells that express the protein in the tissue. The layers are the functional equivalent of applying many transparent overlays on a geographical map, enabling multiplex IHC. Each membrane can be tested for any analyte of interest, so that the selection of targets for analysis is initially ‘open’, until selected antibodies are applied in the second step.