Single-stranded nucleic acids will bind, with a high specificity, complementary nucleic acid sequences. This is followed by a wash to remove all unbound sample. This allows the investigator to visualize and relatively quantitate mRNA transcript levels.
Most protein chips are conceptually similar.
Washing a sample over the chip allows the antibodies to bind the specific proteins in the sample. Arraying many hundreds or thousands of these spots provides a protein chip with the capacity to determine a multitude of different protein levels in parallel. Ok, so that's a protein chip, but it doesn't have any proteins on it, per se. Similar concept to the gene chip. Will be valuable for diagnostics.