Patent ID: 7427513

Claim:
A method for producing an aggregate of surface-modified metallic colloid clusters, the clusters comprising metallic particles and at least one Raman-enhancing organic molecule on a surface of the metallic particles, the method comprising: a) contacting metal cations with a reducing agent in aqueous solution; and b) subsequently heating the aqueous solution, thereby producing metallic colloids; c) modifying the metallic colloid cluster by attaching the Raman-enhancing organic molecule to the surface of the metallic colloid cluster to produce the surface-modified metallic colloid, wherein the Raman-enhancing organic molecule comprises a moiety that has an affinity for the metallic colloid and another moiety that has an affinity for a biomolecule; and d) aggregating a plurality of the surface-modified metallic colloid to form the cluster of surface-modified metallic colloids.