Ordering Ag nanowire arrays by a glass capillary: A portable, reusable and durable SERS substrate

Abstract

Assembly of nanowires into ordered macroscopic structures with new functionalities has been a recent focus. In this Letter, we report a new route for ordering hydrophilic Ag nanowires with high aspect ratio by flowing through a glass capillary. The present glass capillary with well-defined silver nanowire films inside can serve as a portable and reusable substrate for surface-enhanced Raman spectroscopy (SERS), which may provide a versatile and promising platform for detecting mixture pollutions. By controlling the flow parameters of nanowire suspensions, initially random Ag nanowires can be aligned to form nanowire arrays with tunable density, forming cambered nanowire films adhered onto the inner wall of the capillary. Compared with the planar ordered Ag nanowire films by the Langmuir-Blodgett (LB) technique, the cambered nanowire films show better SERS performance.

Review of microfluidic approaches for surface-enhanced Raman scattering

“…To further improve the SERS functionality of capillary-based devices, normal glass capillaries, which are quite cheap but low in transparency, can be replaced by quartz capillaries. The influence from the bending radius of the capillaries must also be considered [45].…”

Recent Developments on Metal Nanoparticles for SERS Applications

“…The EF SERS for these robust solid substrates was in the order of 10 9 against R6G as probe molecules, which was mainly due to the strong coupling of EM fields among the monolayered Ag nanowires. Another well-ordered assembly of Ag nanowires was reported by Liu et al [40] by flowing the nanowires through a glass capillary tube, which then demonstrated as a robust, portable and reusable SERS substrate with significant signal enhancement ( Figure 6). Au nanorods with various aspect ratio were also reported for SERS applications, mostly in the biosensing areas, such as SERS imaging of tumor cells and photothermal heating therapy [41].…”

Magnetically Assembled SERS Substrates Composed of Iron–Silver Nanoparticles Obtained by Laser Ablation in Liquid

“…[3,37] Different approaches to this problem have been used in the past, with promisingr esults, such as electrochemicals tripping, [74] dippingi ns olutions of concentrated acid, [75] ultraviolet-ozone (UVO) cleaning, [76] or metal nanostructures supported on photocatalytic oxides (e.g. The need for reusable substrates for SERS analysis appeared recently as ac ost-effective strategy for repeated analytical assays.…”