Optical Express Monitoring of Internalin B Protein of Listeria Monocytogenes Pathogenic Bacteria Using SERS-Active Silver-Decorated Silicon Nanowires

Surface-enhanced Raman scattering (SERS) is an effective method of optical vibrational spectroscopy, which allows highly sensitive detection of molecules at very low concentrations due to amplification of electromagnetic fields formed by excitation of localized surface plasmons on the surface of noble metal nanostructures. In the presented work a method of manufacturing composite nanostructures of silicon nanowires decorated with silver (AgSiNWs) has been developed. The SERS activity of AgSiNWs for protein detection was investigated using human serum albumin as an example. For the first time, the possibility of rapid diagnosis of internalin B (InlB) protein of pathogenic bacteria Listeria monocytogenes by SERS using the obtained nanostructures was shown. In the spectra of InlB adsorbed on AgSiNWs at different concentrations, distinct peaks corresponding to Raman scattering on protein molecules are observed. Based on the experimental data obtained, the InlB detection limit is calculated to be 4.8 × 10 –9 M. The results presented demonstrate the high potential of synthesized composite nanostructures for diagnostics of various proteins by SERS.