Patent ID: 8093065

Claim:
A method of detecting chemical groups in an analyte in solution with an amplification factor of at least 10 10 , comprising (a) exposing the analyte in solution to microbeads, each microbead composed of (i) a microbead substrate; (ii) a plasmon resonance mirror formed on the surface of the substrate, (iii) disposed over said mirror, a dielectric layer having a thickness of 2-40 nm, and (iv) a plasmon resonance particle layer composed of a periodic array of plasmon resonance particles having a coating effective to bind analyte molecules in a selected size range between 50-200 nm, (b) by said exposing, binding the analyte to the microbeads, (c) irradiating the beads and bound analyte to produce a Surface Enhanced Raman spectrum, and (d) analyzing the Surface Enhanced Raman spectrum produced in step (c) to detect chemical groups in analyte bound to the beads in step (b) according to the Raman spectral features of the chemical groups.