Patent ID: 7858385

Claim:
A method for detecting a binding event between at least one binder and members of a receptor array, comprising the steps of: (a) exposing a plurality of bead-supported and nonradioactive receptors to at least one binder having a chemically associated and nonradioactive element detectable by X-ray fluorescence to form at least one bound, bead-supported receptor-binder complex; wherein the element is selected from the group consisting of P, S, and Br; and wherein the binder is selected from the group consisting of esters, amines, imines, aldehydes, ketones, amides, ethers, olefins, halogenated organic molecules, antibodies, drugs, hormones, steroids, amino acids, nucleic acids, oligomers, oligonucleotides, oligosaccharides, oligopeptides, polyolefins, polyurethanes, polyesters, polycarbonates, polyamines, polyamides, halogenated polymers, polypeptides, polynucleotides, polysaccharides, anions, complex ions, oxoanions, polyoxoanions, phosphate, organophosphates, sulfate, organosulfates, zirconate, agonists and antagonists for cell membrane receptors, toxins, enzymes, enzyme substrates, cofactors, and antibodies; (b) washing said bound, bead-supported receptor-binder complex to remove unbound binder from said bound, bead-supported receptor-binder complex; (c) arraying said bound, bead-supported receptor-binder complex onto a substrate; and (d) detecting a binding event by exposing said bound, bead-supported receptor-binder complex to X-ray radiation in order to generate an X-ray fluorescence signal from said detectable element in said bound, bead-supported receptor-binder complex.