Detecting Viruses Captured Onto The Nanostructured SERS Surface

The indirect intrinsic detection configuration shown in fig 1b can also be used to detect viruses captured by antibodies to increase the detection selectivity. Antibodies can be readily immobilized onto the SERS substrate, and the SERS spectra before and after virus treatment can be obtained to compare Raman signatures of antibody alone versus antibody plus captured virus. The SERS spectra of Ag nanorods coated with the IgG antibodies and viruses captured by these antibodies are shown in fig 5. Of the spectral features apparent in the IgG2a antibody spectrum (fig 5, top), the most intense band at not, vert, similar 1000 cm^-1 most likely arises from the in-plane ring deformation mode of Phe in IgG. Prominent bands are observed in the 1400–1600 cm^-1 region of the RSV and IgG complex spectrum (fig 5, bottom). This is presumably due to selectively enhanced nucleic acid and/or side-chain vibrations, although the amide III protein mode at 1260 cm^-1 may be observed in both the IgG and RSV+IgG spectra. These results show that antibodies or related capture moieties can be used to provide selectivity to SERS biosensing

Fig. 5. SERS spectra of (top) IgG2a antibody complex on Ag nanorod array, (bottom) RSV-IgG2a-Ag nanorod complex.