The use of surface enhanced Raman spectroscopy (SERS) in a competitive affinity binding assay for the detection of prions

The recent reports of spread of transmissible spongiform encephalopathies such as bovine spongiform encephalopathy to humans has led to the need to develop rapid and sensitive methods* for the detection for the infectious agent of these diseases, prions, in a variety of biological samples. A novel surface enhanced Raman spectroscopy (SERS) based method has been developed for the detection of these infectious prions. The assay utilizes the competitive binding of an optically active peptide and prion to a monoclonal antibody specific for a conserved epitope on prion proteins. Colloidal gold adsorbed onto the antibody-peptide or antibody-prion complexes in solution gave rise to the SERS effect. The antibody-peptide complex generated a distinct SERS signal, which was diminished as prion was added to the mixture and displaced the peptide. To date detection of as little as 750 fmol of prion can be achieved via this method.