A multiple-ligand approach to extending the dynamic range of analyte quantification in protein microarrays.

This work describes a concept for extending the dynamic range of quantification in an affinity biosensor assay by using a set of ligands with different affinities toward a common analyte. Three synthetic, biotinylated polypeptides capable of binding a model protein analyte with different affinities (10(-9) M < or = K(d) < or = 10(-7) M) were immobilized in a microarray format on a gold slide covered with an oligo(ethylene glycol)-containing alkane thiolate self-assembled monolayer. A five-element affinity array, comprising single-peptide spots as well as spots where peptides were immobilized in mixtures, was realized by means of piezodispensation.