Patent ID: 8383416

Claim:
A microbead composition for use in detecting chemical groups in an analyte with an amplification factor of at least 10 10 comprising a collection of microbeads, each composed of (a) a microbead substrate; (b) a plasmon resonance mirror formed on the surface of the substrate, (c) disposed over said mirror, a dielectric layer having a thickness of 2-40 nm, and (d) a plasmon resonance particle layer composed of a periodic array of plasmon resonance particles in a selected size range between 50-200 nm and having a coating effective to bind analyte molecules, wherein binding of analyte to the microbeads, and analysis of the microbeads and bound analyte by Surface Enhanced Raman Scattering is effective to produce a Raman spectrum of the chemical groups in the analyte with an amplification factor of at least 10 10 .