Development of a method for fast, sensitive and accurate detection of Legionella pneumophila based on surface enhanced raman scattering

Surface-enhanced Raman scattering (SERS) is a powerful technique for detection and identification of biological structures. SERS-based immunoassay methods are mostly used for the specific detection and identification of bacteria. In this study, a novel SERS-based immunobiosensor for detection of Legionella pneumophila was developed. First, SERS substrate is prepared by deposition of concentrated spherical silver nanoparticles (AgNPs) on a regular glass slides using convective assembly method. Second, the surface was modified with 4-aminothiophenol (4-ATP). 4-ATP was used not only to bound the antibody for L. pneumophila to the surface but also to monitor the changes in frequency of Raman peaks. Then the antibody is bound to the 4-ATP modified surface through amide bond. Finally, the modified surface is incubated with the bacteria and obtained SERS spectra from the surfaces. The changes in frequency of Raman peaks of 4-ATP molecule was monitored to detect the bacteria. The results demonstrated that, L. pneumophila can be detected with SERS-based immunobiosensor based on changes in frequency of Raman peaks of 4-ATP molecule.