Surface–Enhanced Raman Spectroscopy Label–free Detection of DNA Complementary PolyA and PolyT Polybases on Ag/TiO_2 Platform

摘要

An original, robust, and low cost Ag°/TiO_2 platform has been used for the Surface-Enhanced Raman Spectroscopy (SERS) detection of polyA-NH_2 and polyT complementary bases. Three procedures have been assessed to immobilize the polybases in various concentrations on the SERS platform, namely immobili- zation of polybases alone, immobilization of the polyA-NH_2 + polyT mixture, and two-step immobilization of the polyA- NH_2 ·polyT system. Derived SERS spectra have been analyzed and are discussed in terms of spectrum reproducibility, influence of polybase concentration in solution, orientation of polybases at the SERS platform surface, as well as feasibility of complementary polybase hybridization. This study allows us envisaging a simple hybridization procedure using the polyA- NH_2 ·polyT system and an efficient SERS detection of in situ hybridization features through intensity measurements of the adenine vibration mode at 1330 cm~(-1) .