Self-assembled monolayer of NAD at silver surface: a Raman mapping study

Self-assembled monolayer of NAD formed at two different silver surfaces, roughened by ORC or nitric acid/hydrogen peroxide mixture, were investigated by a protocol in combination of SERS technique with Raman mapping. On the basis of analysis of the recorded Raman mapping spectra together with reference to the calculation results of minimized energy conformation of NAD obtained by CS Chem3D software, an adsorption mode of SAM of NAD at silver surface was suggested including adenine moiety of the a perpendicular orientation onto the surface via N7 and amino group as well as a flat orientation for the nicotinamide moiety. The various degree of roughness of silver surface mostly impacted on the dynamic process rather than the thermodynamics of SAM formulation of NAD. The method used is a promising analytical tool in the fields of biosensors or bio-mimic chip devices prepared by SAM process.