Silver Nanowire Micro-Ring Formation Using Immiscible Emulsion Droplets for Surface-Enhanced Raman Spectroscopy

Abstract

Precise and rapid detection of biomolecules is a fast-growing research theme in the field of biomedical engineering. Based on the surface-enhanced Raman scattering, micro/nano-scale structures composed of noble metals (e.g., gold and silver) play a critical role in plasmonics. However, it is still limited to structuring nanomaterials in a specific manner. Here, we investigated a novel surface-enhanced Raman spectroscopy (SERS) application using one-dimensional nanomaterials and micro-encapsulation methods. With the immiscible nature of fluids, the nanomaterials were properly captured inside a number of droplets for encapsulation, deforming to micro-ring nanostructures. To yield uniform sizes of the silver micro-ring structures, a microchannel system was designed to characterize particle sizes via microscopic approaches. We were able to obtain printable silver nanowire micro-ring ink, and investigated the SERS substrate effect of the silver micro-ring structure. This fabrication method can be used in many other SERS-based biomedical engineering applications in the near future.