Figure 1.

(A) Examples of analytical protein microarrays in which different types of ligands with high affinity and specificity (antibodies, antigens, DNA or RNA aptamers, carbohydrates, and small molecules) are printed on a surface. These protein chips can be subsequently used for monitoring the protein expression level, protein profiling, and clinical diagnostics. (B) Protein microarrays fabricated on glass slides to identify protein–small molecule interactions. Fluorescence emission of blue, red, and green indicates the presence of the specific protein–small molecule interactions through coupled Alexa 488, Cy5, and Cy3 dyes. Images in A and B are reproduced with permission from ref (7) (copyright 2003 Nature Publishing Group) and ref (4) (copyright 2000 American Association for Advancement of Science).