1 Reagents, namely, polypeptides, polynucleotides, nucleic acids, antibodies, antigens, lipids, proteins and small chemical molecules, all labeled with metallic light-scattering particles, for scientific or research use; metallic light-scattering particles for use as labels for small molecules for scientific or research use; assay kits comprised of solutions, buffers, reagents, substrates, particles and diluents for detection of target molecules