Label Compound Trapped Ag Nano-gap Bumpy Shell for Highly Sensitive Surface-Enhanced Raman Scattering

Abstract

Surface-enhanced Raman scattering (SERS) is an ultrasensitive vibrational spectroscopic technique which has been applied to various analytical area, especially in bio-sensing and bio-imaging. Recently, this technique has been used to design novel SERS tags consisting of noble metallic nanoparticles (NPs) and specific Raman reporter molecules (RMs). However, the conventional synthetic approaches for SERS tags have been suffered from multi-step and low signal stability. Previously, single-step synthesis of Ag nanoshells (Ag NSs) were reported by our group. In the present work, a further study was performed on the single-step synthesis of SERS tags having nano-gap structure leading to generate highly enhanced unique Raman signal. Ag nano-gap bumpy shells (Ag NBSs) were successfully synthesized in single-step. This unusual burst growth of Ag NBSs was attributed to simultaneous addition of small RMs to reaction media, which in turn led to small Ag NPs formation and simultaneous adsorption of both Ag NPs and RMs. Ag NBSs showed substantially enhanced Raman intensity and better stability over one month period of storage than Ag NSs-based SERS tags prepared by conventional method. Furthermore, various kinds of Ag NBSs were prepared using different Raman RMs, and the possibility for use as multiplex cellular imaging was demonstrated.