Detection of Nucleic Acid Bases by Surface Enhanced Raman Scattering Based on In Situ Photo-Reduced Silver Colloids

In the presence of cyclic organic compounds, the photo-reduced reaction of silver ions could occur under the inducement of the laser irradiation, forming silver colloids of aggregated silver atoms. In this study, the formation of the colloids induced by laser irradiation was proved by means of Raman scattering, UV-Vis spectrum and Scanning Electron Microscope (SEM). The Raman signals of nucleic acid bases were slightly enlarged because of the surface-enhanced Raman scattering activity brought by the aggregation of silver atoms. Furthermore, the experiment results show that Raman spectra with a high signal-to-noise ratio and good repeatability could be obtained by this method and the Raman spectra of nucleic acid bases obtained were similar to those obtained in Lee-Meisel silver colloid and on silver membrane surface. Although there were some new peaks and shifts in our Raman study, the classical characteristic peaks could also be found and used to identify different species. Owing to its simple operation, surface-enhanced Raman scattering (SERS) of colloids prepared by photo-reduced silver nitrate shows great application value in the in situ detection of small molecules.