Gold Nanoparticle-Decorated Porous Silica for Surface-Enhanced Raman Scattering-Based Detection of Trace Molecules in Liquid Phase

Abstract

Development of a facile and cost-effective surface-enhanced Raman scattering (SERS) sensor with high sensitivity for the on-site rapid detection of trace molecules is a compelling need. Here we report how a capillary-based three-dimensional network porous silica material decorated with gold nanoparticles (3D-PSM@AuNPs) serves as an ideal platform for the rapid static liquidphase detection of trace molecules. The SERS sensor is prepared by an in situ polymerization method to form a 3D continuous interconnected porous network in an ultraviolet transparent quartz capillary with a facile fabrication process. The unique porous network of the silica, which could provide a high specific surface area in a focus volume, endows the resultant material with a high density of SERS enhancement sites and a "hot-spot", which has precisely guaranteed the detection sensitivity. More importantly, the unique structure of the capillary could also present an aid to reduce the energy loss of the laser via multiple reflections and thus effectively improve the utilization rate of the laser beam. Using 4-mercaptopyridine (4-MPY) in aqueous solution as a model molecule, the porous silica material exhibits a high detection sensitivity (10 −11 M), excellent stability, and repeatability. Moreover, the obtained 3D-PSM@AuNP sensor is applied for the analysis of phosmet residues on orange peel and vegetables. The results demonstrate that this 3D-PSM@AuNP sensor can successfully realize Raman reporter-free and rapid on-site detection of trace molecules in liquids, which provides a promising platform in various fields of micro-volume liquid sample analysis, especially in liquid biopsy analysis.

Capillary-force-assisted self-assembly of gold nanoparticles into highly ordered plasmonic thin films for ultrasensitive SERS

“…25,26 But in recent years, more and more researchers have taken advantage of the special structure of capillary and apply it to real-life sample detection. [27][28][29][30] The particularity of the capillary is mainly that it has a threedimensional structure, and nanoparticles can be attached to its upper and lower surfaces, and both are located in the effective laser excitation region. The larger surface area effectively improves the utilization of nanoparticles and lasers.…”

Hybridizing aggregated gold nanoparticles with a hydrogel to prepare a flexible SERS chip for detecting organophosphorus pesticides

“…23,24 Therefore, the detection and monitoring of OPs is of significance. Although many instrumentation and sensing methods have been developed for OP detection, [25][26][27][28] the hydrogel SERS chip shows many advantages such as low cost, high sensitivity, rapid detection, and high-throughput. These satisfactory results suggest that the developed hydrogel SERS chip shows great potential in on-site trace analysis for food safety, environmental monitoring, and homeland security.…”

Three-Dimensional Dendritic Au–Ag Substrate for On-Site SERS Detection of Trace Molecules in Liquid Phase

“…Some recent publications have presented methods for the in situ fabrication of microchannel-SERS devices. Chi et al [25] proposed a method for the in situ polymerization of a 3D network porous silica material decorated with gold nanoparticles (3D-PSM@AuNP) in capillary tubes, and the new technique had demonstrated the ability to detect 4-mercaptopyridine in aqueous solution. Rajasimha [26] used a femtosecond laser sintering method to integrate silver nanoparticles onto a fused silica-based channel, forming a uniform, repeatable and large-area microchannel-SERS substrate.…”