Control of protein density on nanoparticles for SERS-based immunoassays

Abstract

The paper presented herein provides a novel Raman mapping procedure developed to pattern-modified gold nanoparticles on planar gold substrates. This work began with the development of a simple approach to the fabrication and reading of protein microarrays based on the use of microfluidic channels in PDMS and SERS detection. The assay consisted of anti-bovine IgG which was tethered to the nanoparticle via a bifunctional coupling agent and surface-bound bovine IgG. The Raman spectral intensity of the symmetric nitro stretch of the DSNB-modified nanoparticle was used as a diagnostic tool for biomolecular interactions. The work described herein seeks to probe the binding event and also addresses the possible causes of the higher signals observed in such binding events. It is also a contribution to an ongoing investigation into the effect of Raman reporter labels on the observed signals in immunoassays which use SERS as the readout technique.