SERS Signal Enhancement of Methylene Blue-embedded Agglomerated Gold Nanorod@SiO2 Core@Shell Composites

Abstract

In medical science, Raman spectroscopy has received considerable attention as the next noninvasive diagnostic imaging technique. However, its clinical applications are limited by the weak signal intensities of Raman active molecules. Previously, we showed that a methylene-blue-loaded gold nanorod@silica (MB-GNR@SiO2) core@shell nanostructure is promising for the development of a cancer theranostic agent due to its excellent surface-enhanced Raman scattering (SERS) performance and synergistic cancer-destroying efficacy. In this study, we successfully synthesized MB-embedded agglomerated gold nanorod@SiO2 (MB-A.GNR@SiO2) composites, in which the many interparticle junctions created by the agglomerated GNRs were able to enhance the SERS signal of the loaded MB by a factor of five compared to MB-GNR@SiO2. This high SERS performance of the present MB-A.GNR@SiO2 could provide us with an approach to explore a rapid and ultra-sensitive SERS detection method for various biological molecules.