Silver (Ag) nanorod array-based detection of oligonucleotide complexes of influenza by surface-enhanced Raman spectroscopy (SERS)

Abstract

Recent progress in substrate nanofabrication has led to the development of Ag nanorod arrays as uniform, reproducible, large area SERS-active substrates with high signal enhancement. These novel nanostructures fabricated by oblique angle vapor deposition (OAD) offer a robust platform for the rapid detection of biological agents and open new perspectives for the development and integration of biomedical diagnostic for clinical and therapeutic applications. Ag nanorod arrays have been investigated as SERS-active substrates for the label-free optical detection of nucleotide complexes by monitoring the surface-enhanced Raman spectra of the oligonucleotide probe-viral target complex. The assays presented in this work consist of oligonucleotide-based arrays immobilized on the surface of a SERS-active substrate that allow binding of viral nucleoprotein constituents of the viruses contained in a commercially available split-virion inactivated influenza vaccine, as well as detection of various influenza RNA strains containing a gene mutation coding for a viral protein associated with high virulence of influenza. Multivariate statistical methods were employed to confirm statistically significant differences between the spectra of the DNA probes and their complexes after binding to the viral targets. These results provide the first evidence for the use of oligonucleotide-modified SERS substrates as diagnostic tools for influenza virus detection in a complex biological matrix. The findings demonstrate that bio-nanotechnology combined with vibrational spectroscopy has the ability to enhance both detection and diagnosis of emerging viral infections while allowing point-of-care testing in clinical applications to rapidly determine disease risk and the appropriate course of action to reduce its spread.