Gold Nanoparticles Based SERS Spectroscopic Assay For Detection Protein-Protein Interaction

Benefit from the extremely high enhancement effect arising from the proximity of nanostructured metal surfaces, surface enhanced Raman scattering (SERS) has been exploited in many studies to observe trace amounts of biologically relevant molecules. In this paper, we developed a highly sensitive and selective assay based on SERS for detection of protein-protein interactions.Firstly, gold nanoparticles with different sizes (13 or 30 nm ) were prepared by varying the ratio of gold to reducing reagent or capping ligand. The as-prepared 13nm and 30nm gold nanoparticles were used as substrates of SERS.Secondly, a sensitive spectroscopic assay based on SERS using gold nanoparticles as substrates has been developed for rapid detection protein-protein interactions. Highly selective recognition of IgG down to 1 ng/ml in solution is demonstrated.Thirdly, we developed a novel microarray based SERS assay for detection of peptide and protein interaction by attachment of gold nanoparticles followed by silver deposition for signal enhancement. In this new spectroscopic assay, peptide is detected down to a limit of 10 fg on the microarray spots. And recognition of standard proteins (protein A and IgG) down to 0.1μg/mL for proteins in solution and 100 fg for proteins on the microarray spots are also demonstrated.