Fiber-optrode SERS probes using plasmonic silver-coated gold nanostars

Abstract

Abstract Surface-enhanced Raman scattering (SERS)-based molecular sensing has emerged as a powerful tool in a wide variety of fields ranging from environmental monitoring, biomedical diagnostics to security applications. As versatile SERS probes, fiber-optrodes (i.e., a SERS substrate integrated on optical fibers) can simultaneously guide excitation laser and collect the Raman signal, enabling remote and in situ sensing capabilities. This characteristic feature makes fiber-optrodes ideal for hazardous environments or for field-ready applications, where sample manipulation has to be minimal. In this paper, we firstly report the development of a fiber-optrode using silver-coated gold nanostars (Au@Ag NS) as highly enhancing SERS active substrate. These optrodes take advantage of the excellent photonic properties of Au@Ag NS to achieve ultra-sensitive sensing properties. Through the immobilization of the Au@Ag NS nanoparticles and the optimization of the optrode-configuration, the proposed SERS sensor’s analytical figures of merit are investigated in detail. The optrode developed herein has a promising prospect for in-field and remote test for trace chemicals and for applications such as direct detection of food additives and biotargets.