Rapid Surface Enhanced Raman Scattering (SERS) Viral Assays

Rapid and accurate detection is the key to controlling the spread of viral pathogens. Recent advances in the field of surface enhanced Raman scattering (SERS) spectroscopy have demonstrated the utility of this technology in diverse research disciplines ranging from surface chemistry and electrochemistry to forensics and the development of protein/nucleic acid sensor technologies. Our long-term goal is to develop a SERS based diagnostic tool for viremia that can be easily adapted for cost effective, portable and compact Raman spectroscopy in a point-of-care facility or field setting.

In this work, an indirect capture model assay using colloidal Au nanoparticles was demonstrated for SERS spectroscopy detection of DNA sequences and viral antigens. The DNA sequence targeted for the indirect capture was derived from the West Nile Virus (WNV) RNA genome and selected on the basis of exhibiting minimal secondary structure formation. Upon incubation with colloidal Au, hybridization complexes containing the WNV target sequence, a complementary capture oligonucleotide conjugated to a strong tethering group and a complementary reporter oligonucleotide conjugated to methylene blue, a Raman label, anchors the resultant ternary complex to Au nanoparticles. This anchoring positions the methylene blue within the required distance from the gold nanoparticles for SERS enhancement.&'