Surface-Enhanced Raman Spectroscopy on Selectively Adsorbed Plasmonic Nanostructures Using Polar Surface Arrays

Abstract

This paper introduces an approach that enables highly adjustable surface adsorption of single plasmonic nanostructures using polar surface arrays. The plasmonic nanostructures are made from DNA origami and functionalized with gold nanoparticles for surface-enhanced spectroscopic techniques. To ensure that the contribution of individual nanostructures to the measured signal can be detected without any interference from the surrounding structures, we aimed to control the distance and set a minimum gap between the nanostructures on the substrate surface. We describe the fabrication process of the polar surface array based on electron beam lithography, followed by functionalization. Our results indicate that the concentration of DNA origami structures and the duration of the incubation primarily affect the number of adsorbed nanostructures. Density functional theory simulation explains the selective adsorption of plasmonic nanostructures due to the substrate surface properties. The spatial arrangement of nanostructures allows for the reliable identification of the Raman signal’s location, while a falsified identification resulting from agglomeration is prevented.