Detection of biomolecules using nanoparticle, surface enhanced Raman scattering tags

Detection tags based upon surface enhanced Raman scattering provide an alternative to the widely used fluorescence methods. Several aspects of these tags are presented in this report. The tags can be made to display many different spectra, thus they can be used for multiplexed detection schemes. They generate a large enough number of photons to be readily detected, and spectra acquired from mixtures of tags can be analyzed giving accurate amounts of the components. The surface of the tags can be easily modified to present common biological molecules (streptavidin and analogues). Finally, we demonstrate their use to quantitatively detect interleukin-4 (IL4) and interleukin-7 (IL7) in a microarray format.