DFT and SERS Study of 15N Full-Labeled Adenine Adsorption on Silver and Gold Surfaces

Abstract

Adsorption of nucleic acid bases on metal surface of nanoparticles has received much attention recently in bio- and nanotechnology, while it still remains a controversial problem in how adenine is adsorbed onto the metal surface. As the nitrogen in adenine plays an important role in the molecular recognition and interaction, the spectral feature related to the nitrogen is the key to analysis of the adsorption configurations. For this purpose, we employed density functional theory (DFT) calculations at B3LYP/6-311+G(d,p) level for the simulation of adsorption configurations, and in the meantime we checked the corresponding surface enhanced Raman spectroscopy (SERS) of 15N fully labeled adenine adsorbed on the surfaces of silver and gold nanoparticles both experimentally and theoretically. The agreement of spectral positions, intensities, and isotopic shifts of the SERS bands, suggests that adenine adsorbed on either silver or gold surface takes the same adsorption configuration in which N7H adenine interac...